I agree with AJ Harran on the flexure issue. From the vantage point you set the camera up at, I could tell every time you applied pressure on the square hole the material flexed, which looks like it compresses the sides, reducing the freedom for the cutter to wobble front-to-back. Anyway, very educational video for me. Thanks!
It seems to me that cutting pressure is proportional to starting hole diameter, broach shape and material. Getting the percentage correct between the hole size and the "across corner" diameter is the trick. Thanks for the tool review Tom, and thanks Brandon for offering it up for testing.
For the larger square, I'd recommend drilling out the corners with smaller holes before drilling out the pilot in the center,. Still able to cut a full form square but with much more cutting clearance so that the broach doesn't have to push that much metal.
Hi Tom, We use several of the rotary tools in production (CNC) for 3/4" square drive socket head aluminum bolts (M24 x 3) and 5/16" hex outside for drive end on some M10 x 1.75 all-threaded 303 stainless studs. Occasionally some other "specialty" sizes for tooling applications are used in the Bridgeport mills. When used in Bridgeport, we use the knee with the spindle fully retracted and locked. The knee has a little better 'control' and not risking an overload of the quill drive. Oh, and YES, it DOES take significant pressure to drive a broach at "full form". Effectively you DO have to develop punching pressures (albeit incrementally) to move that metal. Ken
Now that is a really neat tool! Thanks for the video. In the case of the larger square tool, perhaps a step up process would be in order. Working from smaller squares up to the final....maybe?
I'd been struggling to get a clear mental image on how a rotary broach actually works but this is the best video yet (out of dozens) because the large square rotary broach on the mill really exaggerates what's going on! It seems counterintuitive but when someone struggles to achieve a good result with a proven method I feel you get a better understanding of what the process actually entails.
Great tool and demonstration. Thank you for showing us. We probably aware of a higher percentage of unwanted cross sectional area in converting a round hole into a square compare to hex. The adjacent sides of a 90-deg corner tends to more converge waste material in a direction compare to hex of 120-deg. The forward face, profile, of the cutter may not be designed/finished to extract amount of material of that kind. The lube did little to help extraction, waste material began gum up in each corner, soon combine and piled with the upcoming material, and eventually work hardened into a nasty bump have prevented completion of this cut. Considerations : Could change to heavy duty lube such as grease improve it. The face profile has two concave regions, area with shallow and steeper (concave, radius) angles, reduce the surface area in the shallow region, and to reduce concave radius to steeper region, for material such as aluminum. In addition, we may break the broaching in two cycles, starting with one size smaller die before the finishing size which brings up the tooling and cycle cost.
+YK Chan Hi Chan, You are correct. The starting hole for a square needs to be much larger. The broach did have concave clearance in end but not enough for the amount of material I was attempting to push. Thanks for the comment. Cheers, Tom
Think more support under the work piece for the larger broach will help since the work piece is flexing and adsorbing the 'wobbling' action which probably is making it difficult to cut.
Rigidity, Your spindle is oscillating. Thus reducing the cutting action. This is a huge cutter for the size of holder and rigidity of set up. I have difficulty with a 1/2" square broach and usually chip the broach using a vertical mill. I have never tried a 5/8" square broach. This is a beautiful Rotary Broach holder. Great Video.
Nice review Tom thanks for the test. Going at it kind of cold like that you suddenly find out what you don't know about the tool's little quirks like hole size and perhaps even speed might be a factor.
Thank you Tom and all those involved in the efforts and production of this channel. Merry Christmas, Happy Holidays and Happy New Year to all. May the new year bring you, your families and friends much health, wealth, happiness and peace.
You could hit the corners with a small drill bit then take the center out as well or use a small end mill to get it closer then broach it for good form.
I am surprised the broaches didn't come with a drill chart. I ordered one broach from Polygon Solutions and they sent the chart with it. I made my holder from a threaded tip live center. I think it is much more useful in the lathe than in the mill. I believe the maximum depth of cut is 3x diameter.
Great Video Tom- Can't wait to read the comments from all the 'Broach-guys' to see the shortcuts. Happy holidays to you Tom, your family and all the Oxen! 😃👍
you can drill the corners with a smaller bit to help speed this up and still keep its square shape. removing material from the corners gives a little more wobble to the cutter.
Merry Christmas Tom to you and your Wife I have learned allot very quickly and have you to thank so have a great day and hope to see you in the new year. Thank you
What a neat tool, at least for small broaches, I'd love a torx one. Mate you are not wrong about the force used on that large square, I can see the work bowing :)
Nice video, cheers Tom. Just a thought from seeing the plate bending due to the pressure you were putting on when using the larger broach. You could have drilled out the corners as well with a smaller drill to remove most of the material, hopefully making it a bit easier to push through. Or maybe using a small end mill to rough out the shape to a smaller square. Dan.
Cool tool. I would have liked to hear the difference in price (and maybe tool life) for the broaching bits vs. regular push or pull broaches. Straight broaches are available in hex or square (and also require slightly oversize holes), but will not work in a blind hole. There is also the relative price (and size - if you have a very small shop) of the rotary broach tool vs. some kind of press for pushing a straight broach. I have made one-off hex broaches by cutting the corners off a section of allen wrench. First remove most of the corners for the depth of the hole; drive it in with a hammer. Then cut that tip off and grind away a bit less of the corners; drive that in. Eventually you are driving in a bit of allen wrench with the full hex. Price: one allen wrench of the right size, and some time. You only get a couple of holes before the tool is ruined (allen wrenches aren't all that hard), but if a couple of hex holes is all you need, it works. You can do the same sort of thing with a bit of square key stock, but it is much more difficult to drive and you may need to recut the tool more than once for each step. It really helps to hold these broaching tools in a pair of Vise-Grips™; it keeps them straight and saves the fingers.
Tom, it seems to me that much like a standard push broach, you should have at least two broaches to complete the flats. Think one round hole and two broached. Wow, nice tool, great review!
Had wondered how polygonal holes were made in metal, and now I know one more method than before (multi-ton presses was the way I've seen it done). Then again, I'm just a TH-cam watcher who has never ever set foot in a metal shop :)
Given that a square broach has to remove more material and that a larger broach has to remove more material, I would expect to start with a smaller size if a fully formed shape is needed. (I don't start with a 1" drill if I want to drill a 1" hole in stainless.) Great review.
Hi Tom, I have been reading your book "Metalworking: Doing it Better" and it is excellent! You put so many good tips and stories in there, and it is easy to read. (Especially with all of the pictures)
I think (from my armchair) that just re drilling the 2nd drill bit size for the square would have been sufficient just to clear the big chips, and as another viewer noted, there was a lot of flex in the part that could have been binding up the wobble action. Cool tool review and I'd like to see it working some steel.
excellent review, always wondered how the hex holes were sunk. thanks for the know how Tom. great tool , I wish the maker every success and merry Christmas to you guys.
Tom I would like to see more radical angled cutting edges on that bigger square broach--increase the slicing and lessen the pushing..All in all though a good tool..Ian
Cool tool! The tool has a focus point for the wobble, and that's why the length is critical. The big square tool, as some noted, isn't the same length as the hex tool, so the cutting action is hindered as it's not focused. I suspect the small square broach of the correct length would cut through the piece like butter.
+Richard Freeze Hi Richard, The large square tool is 1.75 overall length the same as the hex and smaller square. It doesn't fit in the box because the head is larger that the hole where the other tools are smaller. Thanks for the comment. Cheers, Tom
Ha! So much for that theory. :) I would surmise then that the length to width ratio is a significant factor. As you point out, the big broach is probably at the limit of the tool's capability. 1.75 / 0.375 = 4.67. 1.75 / 0.630 = 2.78 To keep the 4.67 ration for the 0.63 dia, the 1.75 would have to be 2.93. The angle of the wobble, or maybe the diameter of the rotation, probably has to be changed to put the fulcrum point in the correct position. Great review. Awesome tool. Season's greetings, Tom.
+Richard Freeze All the complicated math can be stalled, larger bit = moving more metal, which either takes more force or a more concave/convex surface on the face of the bit to push as it wobbles. But as Tom was showing when he first drew the bit back out of the hole the chips stopped moving when they met on the sides. That starts taking away from the wobble moving the metal for you and back into pressure broaching. Like i posted above it would be very interesting to see how the grind on the face of the tool could be changed to help move metal easier.
+Richard Schmidtendorff Yes, obviously it takes more force as the size of the bit increases. However, there is a lever arm action at work that gives a mechanical advantage to the cutting action. In a tool such as this the fulcrum point is fixed at a certain distance determined by the angle and diameter of offset, so as the diameter of the cutter increases the mechanical advantage decreases. A larger holder that would accommodate a longer bit is necessary to regain the mechanical advantage. That is what I was trying to convey in my earlier remark about the ratios. In fact if you look at other manufacturers of rotary broaches you will find that their fixed tool holders for larger diameters require longer bits. The shape of the cutting edge that you refer to would affect the angle of keenness and thus the force required to shear; however, with the forces involved in this broaching action, if the angle of keenness is too small the cutting edge is going to fail rather quickly. As Brandon Nichols himself notes in one of his remarks, the maximum diameter of his tool is 0.500 inch. Cheers! Happy Christmas!
Btw the diameter of the bit does not change the fulcrum point or the other 2 axis this bit is moving on in its wobble. In fact the bit corner actually gets more travel or sheer from the cutting edge. You are just trying to move more material and takes more force. As i mentioned the tool cuts until the chips meet and stops moving. If Tom had just ran the same sized bit through the hole taking the intersection of chips out the bit would have started cutting again. I am sure a larger tool with more wobble and changed fulcrum would do better but that is not what i was even talking about.
Hi,I would like to get the opinion from a professional machinist. I going to purchase a drill press and would like to know.is having a power down feed important.?Is it a feature on the drill press that's often used or is barely used?
From my experience with morticing picture frame corners, try a smaller cut first and take progressively larger square cuts. It doesn’t seem like the waste has anywhere to go and clogs up the cut. We could never take the full cut with wood, and had to take smaller chunks at a time.
I have couple of thousand blind 4 mm hexes to make about 5 mm deep per year. I don't have a broach but just grind a tool similar to those in video and just push it in a bit oversized hole. It's not full form but customer doesn't complain.
Dam it! it's too late to have Santa bring me one for Christmas. Very very nice tool and is at the top of my "must have" tools to buy! Great review Tom and congrats to you Brandon for producing a good functional tool!👍👍
Alas, DB Customs appears to be no more. I think drilling some small corners holes in the corners should help with that square brooch quite a bit. Another option would be to start with a smaller square broach, and then enlarge the hole to final size with that broach.
Tom, I read that the bearings only last like 100 holes or so, doesn't that seem a little low to you? Can you see why that is the case? Perhaps a different bearing (taper roller bearings) would improve the life?
Interesting tool. Would be cool to disassemble it so us lay-folk knew how they worked. Although, he might not want you to if he's got any kind of patents currently being approved.
Tool quality looks great. I was thinking that the material being "soft" was being displaced/folded over and forming an interior base stopping the cutting, thus the larger hole. A press broach has an area behind the tooth for shavings and the square has no such relief area. If the test was made on steel I wonder if the same type results would appear, that is where the material is not so "soft" ? Good video and good tool.
Hi Tom: I'm surprised that the maker of the tool didn't provide you with a table of base hole sizes and forcing cone dimensions which are available from broach manufactures for different shapes and sizes. Such dimensions are not to be guessed or experimented because are known factors similar to drill sizes for tapping. Also recommendations as to proper type of lubricant for the process are offered. The tool holders that I'm familiar with, offer broach centering capabilities which I don't see present in this holder. But the proof is in the pudding as they say, and if it works that's all is needed. Regards Jorge
Very informative video. Like a lot of things, you can read about how a process works, but until you see it, you can't get a clear idea of how it works. Do the instructions say if the tool works on steel? Lot more applications for steel than aluminum. Anyway, thanks for a useful demonstration
For the large square hole to work you need better support. the plate is bending and because the tool is cutting in really small increments all the cutting ability is lost. I was hopping the maker of the tool will point it out. Thanks for the video!
Nice review Tom, thanks. The large broach seemed to be approaching the max for your machine stiffness. For most work I guess the feel for the machine is all the feedback an experienced machinist needs, are there fussy jobs that need more feedback? We've made load cells in the past for doing friction stir welding to get constant load on the tool shoulder.
I am not even a machinist novice but I wonder if drilling out the four corners with small bits and following that with then drilling out the center would allow the broach to work its way through. Just a thought.
Great tool review. I like the rotary broach and it is obviously a wonderful tool but I don't think about making a square hole often enough to need one. Thanks for the video.
+Brandon Nichols I had not thought of that. Of course I am sure their are lots of uses I did not think of. I should have been more clear. I do not do a lot of metal working so their are many tools that I do not need enough to get one. This is obviously well made and works great. I think it would be a much needed tool for a professional job shop and a busy hobbyist.
First time I can comment in real time now that I'm caught up. Really enjoying Adam Booth's channel. Thought on your "Meatloaf" series you could tell some more stories -- like "we workin' outside today?" You could call them a "side of Ox Tale Soup." Wishing you and Mrs. Ox a very Merry Christmas, Happy Holidays and a Happy New Year. Oslowe (Mom from Piedmont)
Maybe a set of broaches, two or three sizes to get a full profile square hole. Gronk was putting the muscle to that plate.....Merry Christmas, hope Santa brings everyone all they need:)
How would you make a square hole without the rounded parts from the oversize drilled hole? If the broach needs an oversize hole then it is worthless if you want an actual square or other polygon hole. Or am I missing something? Just curious, I'm a novice and never seen broaching before.
+Brandon Nichols I see, very cool. Can you do any shape? As in, do the shapes have to have equal sides like square, triangle, hex, etc. Or can they have unequal sides?
+Brandon Nichols Awesome, look forward to it. I ask because I have actually milled a rectangular hole but it didn't come out well. Partially because I am not a good machinist but partially because round corners from the endmill, etc. Plus, I wanted it smaller. I appreciate your time! Thanks. By the way, that's a beautiful tool you made.
Would broaching such relatively large sizes be made easier by some kind of two stage broach? i am assuming because of the larger area and the lower surface pressure causes the issue
+jusb1066 I had the same question. Looking at the thickness of those chips of the partial broach you can understand how the pressure needed increases. If you reduce the chip load it should make it easier.
+jusb1066 I was also wondering something similar, as in go up in stages until finish size is reached. The indexing may become a bit more tricky with this approach though. All in all looks be a great tool and well made. Cheers from John and seasons greetings to all from Australia.
I bet if the big broach was a hex instead of a square, it would have breezed through it . . The square has more material to move in the corners than the hex.. Nice piece of kit tho, top job Brandon!
Perhaps with 4 holes drilled close to the corners you could get that square broach pushed thru without such an oversized hole. This is in Alum, no chance it would go thru steel like this.
That's what I was thinking. You'd have to put the c/sink on first, then cut a square with (rounded corners) using a roughing end mill(?) to make life easier on broach. I guess it would be no more alignment effort than setting up to broach a smaller hole. Provided you have the focal length correct, this would greatly extend the maximum broach size for a machine of this stiffness/max tool load limit.
I love that tool! The finish on the holes look nice. When I do stuff like that, I punch the holes. It's faster to punch, but the burrs are large, and the hole finish isn't always great. Another thing is, that to punch holes, I have a big hydraulic that only does one thing... Do you need a milling machine for this type of broaching, or would a drill-press be rigid enough?
I wonder how it works in D2. Seeing as how the plate is flexing with the large part. This type of operation is being used to cut both internal and external gears and splines at much higher production rates than traditional hobbing or shaping operations
It would probably be fine if the hole was smaller and properly sized for the broach. The cutting tool material would drive what it can and can not cut with some size limitation. Thanks for the comment. Cheers, Tom
I've been playing around with Rotary broaching a Keyway, Square is a lot of removal. Seems like once I get a Burr, it has to work exponentially harder (meaning, that mostly it doesn't).
tom the square broach did not fit in the box because maybe it isn't suppose to because its not the 1.75 inch long you stated that tool is designed fore
+dan rasmussen That's what I was thinking when he couldn't get the lid closed on that big square broach. I was thinking, you know, maybe that tool is just a bit oversized?
@@EVguru From the geometry of the wobble action of a rotating wobble broach holder, the distance from the leading edge of the tool back to the holder datum (ie where the shank joins the head) would be critical to the correct action, as Dan implies.
Would it work just drilling out the displaced metal when the going gets too heavy before resuming broaching rather than making the hole larger? Also, will it cut steel?
Just bought a Bridgeport shaper as to why I am here but just a thought; why not use the knee? Yes, that would be more a broach arbor press but I think the low pressure and lack of required relief at the nose( need a deeper cone) clogged the bit. Either way, beautifully made and presented tool, equally fine production and honestly. I have really to stop watching these videos and make something not just fix stuff.
Tom, Thank you for the demo. I never knew what/how a rotary broach worked..now I do. I noticed that when you were cutting the square hole the alum scrap piece was flexing down. Wonder if that had any effect of negating the "vibrating" action of the broach. (about 23:10 or so). Regards, Eric
+esoomreltna Hey Eric, What you couldn't see is how hard I was pulling on the quill lever. I really should have drilled out the four corners prior to broaching. That was 1/2 thick alum to give you an idea how hard I was pulling. Thanks for the comment. Cheers, Tom
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I agree with AJ Harran on the flexure issue. From the vantage point you set the camera up at, I could tell every time you applied pressure on the square hole the material flexed, which looks like it compresses the sides, reducing the freedom for the cutter to wobble front-to-back. Anyway, very educational video for me. Thanks!
It seems to me that cutting pressure is proportional to starting hole diameter, broach shape and material. Getting the percentage correct between the hole size and the "across corner" diameter is the trick. Thanks for the tool review Tom, and thanks Brandon for offering it up for testing.
For the larger square, I'd recommend drilling out the corners with smaller holes before drilling out the pilot in the center,. Still able to cut a full form square but with much more cutting clearance so that the broach doesn't have to push that much metal.
Hi Tom, We use several of the rotary tools in production (CNC) for 3/4" square drive socket head aluminum bolts (M24 x 3) and 5/16" hex outside for drive end on some M10 x 1.75 all-threaded 303 stainless studs. Occasionally some other "specialty" sizes for tooling applications are used in the Bridgeport mills. When used in Bridgeport, we use the knee with the spindle fully retracted and locked. The knee has a little better 'control' and not risking an overload of the quill drive. Oh, and YES, it DOES take significant pressure to drive a broach at "full form". Effectively you DO have to develop punching pressures (albeit incrementally) to move that metal.
Ken
Tom, for square broaches Slater recommends a pilot hole of 1.1 times the broach dimension, .693 for a .630 (5/8 nominal) broach.
so does that mean that you can't practically use the entire perimeter of the broach for cutting?
Nah, you need 2 stages of broaching on that square head.
I seen a guy do same diameter with a hand made dye and a vice. Slow is faster
You can also rough the corners with a smaller endmill.
Now that is a really neat tool! Thanks for the video. In the case of the larger square tool, perhaps a step up process would be in order. Working from smaller squares up to the final....maybe?
I'd been struggling to get a clear mental image on how a rotary broach actually works but this is the best video yet (out of dozens) because the large square rotary broach on the mill really exaggerates what's going on! It seems counterintuitive but when someone struggles to achieve a good result with a proven method I feel you get a better understanding of what the process actually entails.
I wasn't needing one of these until I watched this... Thanks! :)
Great tool and demonstration. Thank you for showing us.
We probably aware of a higher percentage of unwanted cross sectional area in converting a round hole into a square compare to hex. The adjacent sides of a 90-deg corner tends to more converge waste material in a direction compare to hex of 120-deg. The forward face, profile, of the cutter may not be designed/finished to extract amount of material of that kind. The lube did little to help extraction, waste material began gum up in each corner, soon combine and piled with the upcoming material, and eventually work hardened into a nasty bump have prevented completion of this cut.
Considerations : Could change to heavy duty lube such as grease improve it. The face profile has two concave regions, area with shallow and steeper (concave, radius) angles, reduce the surface area in the shallow region, and to reduce concave radius to steeper region, for material such as aluminum. In addition, we may break the broaching in two cycles, starting with one size smaller die before the finishing size which brings up the tooling and cycle cost.
+YK Chan Hi Chan,
You are correct. The starting hole for a square needs to be much larger. The broach did have concave clearance in end but not enough for the amount of material I was attempting to push. Thanks for the comment.
Cheers,
Tom
Think more support under the work piece for the larger broach will help since the work piece is flexing and adsorbing the 'wobbling' action which probably is making it difficult to cut.
+AJ Harran Yeah the plate was flexing quite a bit!
It may even be binding the broach.
Awesome tool! Id like to have one of those around myself. Thanks for the cool tool review Tom.
Me too abom me to" looks ace, make one for us as a project, you do a abom size one Tom normal size. Merry Xmas. Robin
+Brandon Nichols You bet Brandon! Very pro work you have done there.
Rigidity, Your spindle is oscillating. Thus reducing the cutting action. This is a huge cutter for the size of holder and rigidity of set up. I have difficulty with a 1/2" square broach and usually chip the broach using a vertical mill. I have never tried a 5/8" square broach. This is a beautiful Rotary Broach holder. Great Video.
Nice review Tom thanks for the test. Going at it kind of cold like that you suddenly find out what you don't know about the tool's little quirks like hole size and perhaps even speed might be a factor.
Thank you Tom and all those involved in the efforts and production of this channel.
Merry Christmas, Happy Holidays and Happy New Year to all.
May the new year bring you, your families and friends much health, wealth, happiness and peace.
You could hit the corners with a small drill bit then take the center out as well or use a small end mill to get it closer then broach it for good form.
one of the builds I want to do on my channel is a lathe rotary broach. it spins rather than wobbles and it rotates with the work.
I am surprised the broaches didn't come with a drill chart. I ordered one broach from Polygon Solutions and they sent the chart with it. I made my holder from a threaded tip live center. I think it is much more useful in the lathe than in the mill. I believe the maximum depth of cut is 3x diameter.
Don’t size the hole based off the size of the broach flats, they’re meant to cut a larger form than the tool
Great Video Tom- Can't wait to read the comments from all the 'Broach-guys' to see the shortcuts. Happy holidays to you Tom, your family and all the Oxen! 😃👍
you can drill the corners with a smaller bit to help speed this up and still keep its square shape. removing material from the corners gives a little more wobble to the cutter.
Merry Christmas Tom to you and your Wife I have learned allot very quickly and have you to thank so have a great day and hope to see you in the new year. Thank you
it looks like a lovely tool i made one a while back and considering the work involved its a good price
Thumbs up, A good honest test. If i had a mill, I would buy one.
Cool tool, weebles wobble but they don't fall down. Merry Christmas and all the best in the New Year
What a neat tool, at least for small broaches, I'd love a torx one. Mate you are not wrong about the force used on that large square, I can see the work bowing :)
A very cool tool! I have never seen one in action before. That was a lot of fun! Thanks for the review!
Nice video, cheers Tom.
Just a thought from seeing the plate bending due to the pressure you were putting on when using the larger broach. You could have drilled out the corners as well with a smaller drill to remove most of the material, hopefully making it a bit easier to push through. Or maybe using a small end mill to rough out the shape to a smaller square.
Dan.
Cool tool. I would have liked to hear the difference in price (and maybe tool life) for the broaching bits vs. regular push or pull broaches. Straight broaches are available in hex or square (and also require slightly oversize holes), but will not work in a blind hole. There is also the relative price (and size - if you have a very small shop) of the rotary broach tool vs. some kind of press for pushing a straight broach.
I have made one-off hex broaches by cutting the corners off a section of allen wrench. First remove most of the corners for the depth of the hole; drive it in with a hammer. Then cut that tip off and grind away a bit less of the corners; drive that in. Eventually you are driving in a bit of allen wrench with the full hex. Price: one allen wrench of the right size, and some time. You only get a couple of holes before the tool is ruined (allen wrenches aren't all that hard), but if a couple of hex holes is all you need, it works. You can do the same sort of thing with a bit of square key stock, but it is much more difficult to drive and you may need to recut the tool more than once for each step. It really helps to hold these broaching tools in a pair of Vise-Grips™; it keeps them straight and saves the fingers.
Tom, it seems to me that much like a standard push broach, you should have at least two broaches to complete the flats. Think one round hole and two broached.
Wow, nice tool, great review!
How much offset is in the wobble ?
Aluminum doesn't count, does it work on steel ?
Had wondered how polygonal holes were made in metal, and now I know one more method than before (multi-ton presses was the way I've seen it done). Then again, I'm just a TH-cam watcher who has never ever set foot in a metal shop :)
Looks solid, very American of you Brandon. When the day comes to get a "DB 'D'a 'B'roach" It'll be one of yours.
Thanks Tom, for the review.
From my family to yours a Merry Christmas and a very Happy New Year.
Thanks for making this video, easy to watch and good information.
Given that a square broach has to remove more material and that a larger broach has to remove more material, I would expect to start with a smaller size if a fully formed shape is needed. (I don't start with a 1" drill if I want to drill a 1" hole in stainless.)
Great review.
Hi Tom, I have been reading your book "Metalworking: Doing it Better" and it is excellent! You put so many good tips and stories in there, and it is easy to read. (Especially with all of the pictures)
I think (from my armchair) that just re drilling the 2nd drill bit size for the square would have been sufficient just to clear the big chips, and as another viewer noted, there was a lot of flex in the part that could have been binding up the wobble action.
Cool tool review and I'd like to see it working some steel.
Great video. Definitely seeing the need for a rotary broach in my garage workshop. 👍
excellent review, always wondered how the hex holes were sunk. thanks for the know how Tom. great tool , I wish the maker every success and merry Christmas to you guys.
This isn’t second review in this video.
My thoughts? Are we dealing with work hardened material?
Tom I would like to see more radical angled cutting edges on that bigger square broach--increase the slicing and lessen the pushing..All in all though a good tool..Ian
What happened to the baby bullet build ?
Cool tool! The tool has a focus point for the wobble, and that's why the length is critical. The big square tool, as some noted, isn't the same length as the hex tool, so the cutting action is hindered as it's not focused. I suspect the small square broach of the correct length would cut through the piece like butter.
+Richard Freeze Hi Richard,
The large square tool is 1.75 overall length the same as the hex and smaller square. It doesn't fit in the box because the head is larger that the hole where the other tools are smaller. Thanks for the comment.
Cheers,
Tom
Ha! So much for that theory. :) I would surmise then that the length to width ratio is a significant factor. As you point out, the big broach is probably at the limit of the tool's capability.
1.75 / 0.375 = 4.67. 1.75 / 0.630 = 2.78
To keep the 4.67 ration for the 0.63 dia, the 1.75 would have to be 2.93. The angle of the wobble, or maybe the diameter of the rotation, probably has to be changed to put the fulcrum point in the correct position.
Great review. Awesome tool.
Season's greetings, Tom.
+Richard Freeze All the complicated math can be stalled, larger bit = moving more metal, which either takes more force or a more concave/convex surface on the face of the bit to push as it wobbles. But as Tom was showing when he first drew the bit back out of the hole the chips stopped moving when they met on the sides. That starts taking away from the wobble moving the metal for you and back into pressure broaching. Like i posted above it would be very interesting to see how the grind on the face of the tool could be changed to help move metal easier.
+Richard Schmidtendorff Yes, obviously it takes more force as the size of the bit increases. However, there is a lever arm action at work that gives a mechanical advantage to the cutting action. In a tool such as this the fulcrum point is fixed at a certain distance determined by the angle and diameter of offset, so as the diameter of the cutter increases the mechanical advantage decreases. A larger holder that would accommodate a longer bit is necessary to regain the mechanical advantage. That is what I was trying to convey in my earlier remark about the ratios.
In fact if you look at other manufacturers of rotary broaches you will find that their fixed tool holders for larger diameters require longer bits.
The shape of the cutting edge that you refer to would affect the angle of keenness and thus the force required to shear; however, with the forces involved in this broaching action, if the angle of keenness is too small the cutting edge is going to fail rather quickly.
As Brandon Nichols himself notes in one of his remarks, the maximum diameter of his tool is 0.500 inch.
Cheers! Happy Christmas!
Btw the diameter of the bit does not change the fulcrum point or the other 2 axis this bit is moving on in its wobble. In fact the bit corner actually gets more travel or sheer from the cutting edge. You are just trying to move more material and takes more force. As i mentioned the tool cuts until the chips meet and stops moving. If Tom had just ran the same sized bit through the hole taking the intersection of chips out the bit would have started cutting again. I am sure a larger tool with more wobble and changed fulcrum would do better but that is not what i was even talking about.
Tom, Could you tell me where you got that little speed square? I've never seen one that small
Hi,I would like to get the opinion from a professional machinist. I going to purchase a drill press and would like to know.is having a power down feed important.?Is it a feature on the drill press that's often used or is barely used?
From my experience with morticing picture frame corners, try a smaller cut first and take progressively larger square cuts. It doesn’t seem like the waste has anywhere to go and clogs up the cut. We could never take the full cut with wood, and had to take smaller chunks at a time.
I wonder if a hammer drill used in hammer only mode, properly positioned can be used to do the job...
I have couple of thousand blind 4 mm hexes to make about 5 mm deep per year. I don't have a broach but just grind a tool similar to those in video and just push it in a bit oversized hole. It's not full form but customer doesn't complain.
Tom, I think you should try the big square broach with better support under the work and use the knee instead of the quill...
Dam it! it's too late to have Santa bring me one for Christmas. Very very nice tool and is at the top of my "must have" tools to buy! Great review Tom and congrats to you Brandon for producing a good functional tool!👍👍
Enjoyed...happy holidays Tom!....test piece is AL, any idea of performance in steel?
Alas, DB Customs appears to be no more. I think drilling some small corners holes in the corners should help with that square brooch quite a bit. Another option would be to start with a smaller square broach, and then enlarge the hole to final size with that broach.
Tom, I read that the bearings only last like 100 holes or so, doesn't that seem a little low to you? Can you see why that is the case? Perhaps a different bearing (taper roller bearings) would improve the life?
Nice review, Tom.
Merry Christmas to you and your missus.
Thanks,
John
Very cool tool.. nice video ! and compliments to DB Customs
Interesting tool. Would be cool to disassemble it so us lay-folk knew how they worked. Although, he might not want you to if he's got any kind of patents currently being approved.
Everybody need a box with full set of heads! Just perfect as is! Thank You for review!
Merry Christmas Tom and have a great new year.
Is it possible that the cutting fluid is causing trouble? A hydraulic cushion, preventing the broach from cutting as well as possible?
Tool quality looks great. I was thinking that the material being "soft" was being displaced/folded over and forming an interior base stopping the cutting, thus the larger hole. A press broach has an area behind the tooth for shavings and the square has no such relief area. If the test was made on steel I wonder if the same type results would appear, that is where the material is not so "soft" ?
Good video and good tool.
Hi Tom: I'm surprised that the maker of the tool didn't provide you with a table of base hole sizes and forcing cone dimensions which are available from broach manufactures for different shapes and sizes. Such dimensions are not to be guessed or experimented because are known factors similar to drill sizes for tapping. Also recommendations as to proper type of lubricant for the process are offered. The tool holders that I'm familiar with, offer broach centering capabilities which I don't see present in this holder. But the proof is in the pudding as they say, and if it works that's all is needed.
Regards
Jorge
Now, I need one and the website is not working.
There is the same for the BTR (hexagonal)?
Very informative video. Like a lot of things, you can read about how a process works, but until you see it, you can't get a clear idea of how it works. Do the instructions say if the tool works on steel? Lot more applications for steel than aluminum.
Anyway, thanks for a useful demonstration
For the large square hole to work you need better support. the plate is bending and because the tool is cutting in really small increments all the cutting ability is lost. I was hopping the maker of the tool will point it out. Thanks for the video!
Over all a very nice tool . I really like it Tom .. Thumbs up man !!
Well done. I thought it was an honest, tell it like it is evaluation, without pandering to the maker for supplying a free tool.
Nice review Tom, thanks. The large broach seemed to be approaching the max for your machine stiffness. For most work I guess the feel for the machine is all the feedback an experienced machinist needs, are there fussy jobs that need more feedback? We've made load cells in the past for doing friction stir welding to get constant load on the tool shoulder.
How flat do you think the bottom of the borached shapr would be if it were used as a counterbore?
I am not even a machinist novice but I wonder if drilling out the four corners with small bits and following that with then drilling out the center would allow the broach to work its way through. Just a thought.
Probably worth to broach the big hole with a slightly smaller cutter first to take some of the bulk off.
PS: Merry Christmas!
Great tool review. I like the rotary broach and it is obviously a wonderful tool but I don't think about making a square hole often enough to need one. Thanks for the video.
+Brandon Nichols I had not thought of that. Of course I am sure their are lots of uses I did not think of. I should have been more clear. I do not do a lot of metal working so their are many tools that I do not need enough to get one. This is obviously well made and works great. I think it would be a much needed tool for a professional job shop and a busy hobbyist.
Hi , i am new on your Chanel. How the circular hole size is determined prior to broaching?
First time I can comment in real time now that I'm caught up. Really enjoying Adam Booth's channel. Thought on your "Meatloaf" series you could tell some more stories -- like "we workin' outside today?" You could call them a "side of Ox Tale Soup."
Wishing you and Mrs. Ox a very Merry Christmas, Happy Holidays and a Happy New Year.
Oslowe (Mom from Piedmont)
Maybe a set of broaches, two or three sizes to get a full profile square hole. Gronk was putting the muscle to that plate.....Merry Christmas, hope Santa brings everyone all they need:)
would 4 smaller holes work better for the square broach?
Good review Tom. Happy holidays to you and yours.
Hi Tom, That was a great tool review on what looks like a really nice tool. Have a Merry Christmas and Happy New Year Matt C.
How would you make a square hole without the rounded parts from the oversize drilled hole? If the broach needs an oversize hole then it is worthless if you want an actual square or other polygon hole. Or am I missing something? Just curious, I'm a novice and never seen broaching before.
+Brandon Nichols I see, very cool. Can you do any shape? As in, do the shapes have to have equal sides like square, triangle, hex, etc. Or can they have unequal sides?
+Brandon Nichols Awesome, look forward to it. I ask because I have actually milled a rectangular hole but it didn't come out well. Partially because I am not a good machinist but partially because round corners from the endmill, etc. Plus, I wanted it smaller. I appreciate your time! Thanks. By the way, that's a beautiful tool you made.
Would broaching such relatively large sizes be made easier by some kind of two stage broach? i am assuming because of the larger area and the lower surface pressure causes the issue
+jusb1066 I had the same question. Looking at the thickness of those chips of the partial broach you can understand how the pressure needed increases. If you reduce the chip load it should make it easier.
+jusb1066 I was also wondering something similar, as in go up in stages until finish size is reached. The indexing may become a bit more tricky with this approach though. All in all looks be a great tool and well made. Cheers from John and seasons greetings to all from Australia.
+joandar1 he indexed it with a square, so I dont see why he couldn't have done that for each progressive size (-8
La brocha de perfil cuadrado de 2.5, va bien, solo que debe retirar demasiado material, en comparación con el hexagonal, pero va bien!
thanks for the review.. always thought it would be something that would be nice to have.
I bet if the big broach was a hex instead of a square, it would have breezed through it . . The square has more material to move in the corners than the hex.. Nice piece of kit tho, top job Brandon!
Perhaps with 4 holes drilled close to the corners you could get that square broach pushed thru without such an oversized hole. This is in Alum, no chance it would go thru steel like this.
That's what I was thinking. You'd have to put the c/sink on first, then cut a square with (rounded corners) using a roughing end mill(?) to make life easier on broach. I guess it would be no more alignment effort than setting up to broach a smaller hole. Provided you have the focal length correct, this would greatly extend the maximum broach size for a machine of this stiffness/max tool load limit.
I love that tool! The finish on the holes look nice.
When I do stuff like that, I punch the holes. It's faster to punch, but the burrs are large, and the hole finish isn't always great.
Another thing is, that to punch holes, I have a big hydraulic that only does one thing...
Do you need a milling machine for this type of broaching, or would a drill-press be rigid enough?
I wonder how it works in D2. Seeing as how the plate is flexing with the large part. This type of operation is being used to cut both internal and external gears and splines at much higher production rates than traditional hobbing or shaping operations
It would probably be fine if the hole was smaller and properly sized for the broach. The cutting tool material would drive what it can and can not cut with some size limitation. Thanks for the comment.
Cheers,
Tom
Ox, at 16:57 ... The issue is it is hitting on the sidewalls of the tooling... It is hitting the "deck surface"; it is being limited in it's axis...
maybe you could use a small endmill to make the hole a bit more square looking before using the large broach
Thanks again Tom
I've been playing around with Rotary broaching a Keyway, Square is a lot of removal. Seems like once I get a Burr, it has to work exponentially harder (meaning, that mostly it doesn't).
tom the square broach did not fit in the box because maybe it isn't suppose to because its not the 1.75 inch long you stated that tool is designed fore
+dan rasmussen That's what I was thinking when he couldn't get the lid closed on that big square broach. I was thinking, you know, maybe that tool is just a bit oversized?
+dan rasmussen I think the problem is the length of the head, not the whole tool.
@@EVguru From the geometry of the wobble action of a rotating wobble broach holder, the distance from the leading edge of the tool back to the holder datum (ie where the shank joins the head) would be critical to the correct action, as Dan implies.
Would it work just drilling out the displaced metal when the going gets too heavy before resuming broaching rather than making the hole larger?
Also, will it cut steel?
Take a drink every time this dude says “ok?”.
What would happen if you drilled 1/8" holes inside the corners of the square then the center hole
If you are an experienced machinist that's the first thing that pops in your head
Just bought a Bridgeport shaper as to why I am here but just a thought; why not use the knee? Yes, that would be more a broach arbor press but I think the low pressure and lack of required relief at the nose( need a deeper cone) clogged the bit. Either way, beautifully made and presented tool, equally fine production and honestly. I have really to stop watching these videos and make something not just fix stuff.
Hi John,
A larger starting hole would have made a world of difference here. Thanks for the comment.
Cheers,
Tom
Could you run through with a smaller broach 1st? If you are even only close on orientation you could still get full form from the final size.
Tom, Thank you for the demo. I never knew what/how a rotary broach worked..now I do. I noticed that when you were cutting the square hole the alum scrap piece was flexing down. Wonder if that had any effect of negating the "vibrating" action of the broach. (about 23:10 or so). Regards,
Eric
+esoomreltna Hey Eric,
What you couldn't see is how hard I was pulling on the quill lever. I really should have drilled out the four corners prior to broaching. That was 1/2 thick alum to give you an idea how hard I was pulling. Thanks for the comment.
Cheers,
Tom
Maybe try using a smaller broach of the same shape, then stepping up to the full form broach for the finishing pass?
It might help if you better supported it from the bottom, the part was flexing quite a bit, which would reduce the cutting stroke.
Liquid love. Lol. Great tool. How else can you do blind holes in hex without one of these?