Making an indexing attachment for the lathe
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- เผยแพร่เมื่อ 6 มิ.ย. 2024
- In this video I design and build a universal indexing attachment for the lathe utilising an expanding mandrel and some 3D printed index plates. This I will be using in future videos to machine the graduations needed for dials etc. This design should work on most lathes with a hollow spindle bore and will be sharing it with my Patreon supporters;
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Timestamps
0:00 Introduction
0:17 What problems do we need to solve?
01:10 Design
02:59 Machining the expanding mandrel
10:53 Drilling the bolt hole pattern
12:45 Milling the slots
14:23 Making the standoff
14:42 Making the cone
15:25 Indexing plates
16:23 Installing and use
18:08 Testing
19:54 Conclusion
My tip for when you break a tap off in a part, especially in aluminum, is to just throw it away and pretend it never happened.
Haha! Indeed.
If you have a spin indexer then you have your 360 marking positions.
Sorry wrong place.
This happens when you don't back off a half turn for every turn to break burrs and clear chips. This is a method of work taught in old school fabrication. In over fifty years of machine fabrication I broke only one tap. That was the first one, I learn quick. All I see now is keep turning and most don't even bother to lubricate the tap and they don't understand why it broke. I bought metric and S.A.E. tap and die sets when I became a machinist and replaced the one tap that broke, and four others over time that wore out. Both sets are almost as old as me!
Just found your channel. I appreciate you leaving in the errors and explaining how you went about fixing them. Very helpful as I make plenty mistakes myself.
Thanks Alanna!
@@joneseymakesAh yes, much like a carpenters skill is really based on how well he fixes his mistakes.
I thoroughly enjoyed every second of this build, especially the mistakes. Videos like these will build the confidence of any beginner machinist or hobbyist. Thank you for sharing!!
One thought that I have is making the holes in the 3D printed parts a bit larger so you could use a larger pin that is slightly shorter than the thickness of the two printed parts, and have a threaded hole in the pin for a screw with a large diameter truss head to squeeze the two printed parts together for insurance of no play.
Thanks! Great ideas, thanks for sharing.
I like the use of machined and 3d printed parts together in a project. Nice work
Thank you very much!
Love your stuff Jonsey, keep up the great work!
Thanks! Will do!
Throughly enjoyed you index plate program and feel so much better that I`m not the only one who has small hash up... Thankyou.
Thanks Dave, much appreciated!
very good design and implementation
Thanks!
There is a simpler way to index the spindle and all you need is a dial indicator. It is a bit tedious but if you are only going to index the spindle once in a blue moon it's not too bad of a job. The trick is to realize that when cutting threads, the spindle is coupled to the lathe's carriage. Then here you want to invert the process. Normally you only think of the carriage movement in terms of full spindle rotation, e.g. when cutting ten threads per inch each time the spindle rotates once the carriage moves 0.100". Now if you only rotated the spindle 1/2 turn the carriage would move 0.050". If you rotated the spindle 1/100th of a revolution the carriage would move 0.001". Now if you have a dial indicator set up to measure the movement of the carriage and move the carriage 0.001" the spindle would rotate 1/100th of a revolution. Just the thing to scribe the dial you are making. Cut the scribe mark with the lathe's compound feed and remember to shorten the length of the compound fed scribed mark to compensate as the carriage is advanced for each index position.
You can use any thread, inch or metric, that you like and you can scribe any number of divisions that are needed. E.g. if the lathe is set to cut 5tpi and you need 100 divisions then the carriage will move 0.002" for each index position.
Disconnect the power to the lathe when doing any work like this. I use a block of wood lightly wedged between the spindle and the lathe bed to hold the plot steady while the scribe mark is made.
Cheers from NC/USA
That's a great way of thinking outside the box !!! A bit klunky, but it works.
That's ingenious, I would never have thought of that. Thanks very much for the tip, I'll give that a shot at some point.
Genius! Thank you for changing my life :)
This is very tedious for, say, anything more than 12 divisions. Although the indicator can measure the displacement of the lathe Z-axis very accurately, most change gear trains I have used have plenty of backlash. So a practice must be found to reproducibly take up the backlash for each scribe.
@@aj7utu That's the purpose of wedging the spindle. Once the gear train is under a load the backlash is eliminated. Note that if cutting a thread the backlash is taken up every time the half-nut is engaged to pull the carriage along.
Absolutely amazing mate! Keep up the great work. Look forward to seeing what else you create in the future!😀
Thanks a lot James!
I found this and watched to the end. Went to find the rest of your content and discovered I've watched it all. Now subbed and notified. Your content is great and thank you
Welcome aboard! Thanks for watching.
This is an excellent design concept, but one should never compromise accuracy with poorly thought-out or executed setups. looking forward to seeing the finished product.
This is outstanding!! New to the channel definitely subbing 👍🏼 Love this
Great to have you on board Keith!
Some tapping fluid would go a long way towards avoiding broken taps. Also, couldn't you use the multi-hole function on your DRO to drill 36 holes in a circular plate, avoiding the 3D printed parts altogether? Keep up the vids, love seeing this stuff!
Thanks. Yes I could make these out of metal i suppose. I wanted to see if the 3D printed design would work first though. If the prints don't stand up I'll machine them in the end.
@@joneseymakes Make the back plate by 3d printing with undersized holes. That way you can have the numbers and accurate holes and bore finished on the mill. Same for the fixed plate. Best of both worlds. You could probably redo the existing holes slightly larger and make a new pin to suit for a more accurate result.
You should be aware that spiral flute taps are weaker than straight flute taps so easier to be caught out and so snap them. For through holes spiral point are the best option, they push the waste ahead of the tap.
@@martinconnelly1473 depends of the helix direction, most spiral taps are for power tapping, right hand helix pulls the swarf spiral out of the hole, you are quite right about left hand helix, use only on blind holes, or use thread milling if cnc. good taps for maleable materials are roll taps, very expensive but worth it in the number of tapped holes especially in 316 etc
@@crozwayne Don't confuse spiral point and spiral flute, they are different things. Spiral flute taps are weaker than straight flutes because the spiral flutes are deeper to allow swarf to escape the hole. The spiral point taps push the swarf ahead of the tap but have the same depth of flute as straight flute taps. Pushing the swarf ahead of the tap requires a through hole to let this swarf out.
He could but where’s the fun in that.
It’s nice to find a channel that shows some of the cock ups we all make and it just edit them out. I feel right at home. 👍
Haha! Thanks Jim.
Thanks for sharing this nice solution
You’re welcome
Nice job. We shared this video on our homemade tools forum this week 😎
Excellent, thank you!
Excellent job, great video, keep'um coming..
Thanks! Much appreciated.
Wow finally a pleasing video .
Brilliant idea! I'll make me one in steel! Thank you for sharing!
You’re welcome!
Well done! I like the 3d printed parts
Thank you! Cheers!
Very cool. I’m interested in building one of these. Good job.
You have a new subscriber.
Paul
Thanks Paul, good to have you on board.
Very interesting, thank you for the video.
You’re welcome!
My submit that was a great design very well done sir
Thanks!
To err is human, as long as the tool is consistent, all good.
Looking forward to the next build.
Cheers
Thanks!
Nice build, on my list to build a version for my 10ee
Thanks! Good luck!
Interesting project. I will be back to see how this comes out.
Thanks, much appreciated.
In the states, we have "Tap magic" and "Anchor lube" among others, but i love tap magic for use in aluminum. That and backing off after every 1 to 2 turns to clear the chip, evem on spiral flute.
As for the fixture, great thinking. Just needs refining as all good ideas do.
Thanks! Yes, I don't know why I didn't think to use lubricant. Serves me right!
WD40 also serves as an excellent cutting fluid for aluminum.
love it!
Nice work
Thanks!
That looks like a great approach to accurate indexing on the lathe. With regards to breaking taps, we’ve all done it. However, if the tap is sharp and you use lube then you shouldn’t break a tap, especially in aluminium with a through hole. If tapping by hand, for every half turn in, take a quarter turn out to break the swarf and repeat.
Great videos, keep ‘em coming 😜👏💪💥
Thanks very much!
smart design kudos
Thanks
James over at Clough42 did a good video a while back where he investigated the sizing of 3d printed parts and then changed the settings in his slicer to compensate for the errors. I did a similar thing last weekend I was tapping M3 hole in 5mm thick leaded steel, this was the last operation and the first 3 went fine but the last hole broke the tap just as the tap was coming out of the far side of the 2.5mm pilot hole. There were a few blue words and when I had calmed down and retrieved my dummy I decided 3 cap heads would do the job just fine after using a punch to break off the protruding bits of tap. I like the design and have often wondered what to do with that drag engraver I bought 5 years ago!
Thanks Michael. I can resize the 3D prints easy enough. Because I'm sharing this design with my Patrons I wanted to make the 3D print a standard size though and find a way to machine the shaft to that size. Hopefully that means more people will be able to make this successfully if that makes sense.
OH, Lovely. I am making one, Thanks!
Glad to hear it, thanks!
@@joneseymakes Are you offering your stl files ?
@@EmptyPocketProductions Yes, to my Patreon supporters
Nice build and save. Good to see I'm not the only one that's accident prone 😆
I'd have gone the route of adding an optical encoder and reading that off an Arduino. You'll still need a spindle lock, but the angular positioning will be more accurate. One advantage is that you can use the setup to add an electronic leadscrew, incremental improvements 🚀
That would be a good project
Olá amigo, gostei do projeto muito bem pensado e elaborado!!!
Lhe desejo muita saúde e cada vez mais sucesso!!!
Olá amigo, gratias tibi valde!!
good job 👍
Thanks!
Brilliant
Thanks!
I dont break taps often, but I feel like it always happens on the last hole. Cheers
Always the way eh?! Cheers
Epic Try mate... Keep at it. I do a lot of 3d printing and getting it tweaked in is an art... Trust me Ive Been pushed to the edge.
Cheers, another video coming soon with my attempts to get this right.
Nice to see what others have done for universal indexing tools for the lathe.
I made a similar indexing system except no venier scale. I designed a 3D printable prototype for the mount that I made available on thingieverse. But machined the final parts out of aluminum for extra rigidity. Mine is based on a two piece external taper-loc design similar to commercially available hubs used to mount pulleys, wheels and other such devices to shafts.
The taper loc hub clamps to the spindle by drawing a cone taper into a wedge ring, exerting pressure both inwards and outwards to clamp both the hub to the spindle and the indexing plate to the hub. An indexing pin is held in a mount fastened to the head stock. I made multiple indexing plate options based on how oxtools modified a 5C spindexer with external indexing plates with multiple rows of holes.
When the indexing is not being used the indexing pin and plate is removed and substituted for a disc with a magnet array and a hall effect sensor for a tachometer and surface feet per minute calculator.
I like that I've not seen a solution such as yours before
Thanks John, you solution sounds interesting. I intend to use multiple rows of hols in my next version.
@@joneseymakes I initially was going to use expanding mandrel like yours but the lathe cover position did not permit this option for use of the same set up to hold a rotor with my magnet array for the tach and surface feet per minute calculator.
I have to get the DRO installed on my mill so I can make a vernier piece like yours and adapt my mount to work with it.
Could you please post a link to the thingaverse page for your lathe external taper-loc design ? Thanks in advance ...
@@llamatrails2 sorry, youtube deletes links.
I have used an old carbide end mill to cut out taps to great effect. What i found very effevtive was broken end mill that i shrpened into a kind of pyramid. Removed many taps with that. (was tapping 304 to m3)
Great tip! Thanks!
Hi! In order to remove a piece of steel from aluminum, you can boil the part in water with citric acid - this will not harm the aluminum
Nitric acid does the same but care should be taken as it is dangerously active,
Neat design. I might build one for my Myford. Over the years I've found the best way to get broken taps out, is to not break them in the first place. Use proper tapping fluid for the material you're tapping. I use A9 for aluminum. Proper type of tap helps a lot too. A spiral point tap would have been better in your situation. Save the spiral flute taps for blind holes.
Cheers for the tips Dan.
Have a look at the tables at the back of the model engineering book titled 'Taps, Drills and Dies' by 'Tubal Cain'. The author recommends using bigger tap drill sizes than standard. The slightly bigger hole greatly reduces the chance of breaking a tap. The trade off is a very slight reduction in thread engagement.
Good idea, thanks for the tip
The recommended size is for super professional work, probably assuming three taps stages. Making small non critical parts on the revolver lathe I routinely made the fit less snug to work faster and easier. Never broke a tap,but the material was mainky automation steel and brass.
I believe you can submerge the aluminum part in a concentrated solution of alumn and water. It dissolves ferrous metals but won’t affect the aluminum.
yes - saturated solution of HOT water and alum. Also helps to warm the part. takes about 6 hours to dissolve the tap. Heat makes it work faster.
Thanks for the tips!
You can see this technique in action on the JohnSL channel.
@@joneseymakes AVE did "Manly-man skills: Remove a broken tap the hard way." about 7 years ago showing this. & I did "Alum vs FCAW!!!" about 6 years ago proving it works getting steel out of copper too...
MOST interesting! Loved it. Except for the errors, all of which were foreseeable. You need a vertical tapping stand above all.
Happy user of the change gear approach here. Regarding the broken tap, if it's sticking out you may be able to grind a slot in it and use a flathead screwdriver to get it out
Thanks, I tried that with no luck.
@@joneseymakes too bad, m3 probably is a bit on the small side indeed for that to work.
Great work man. AvE did a good vid on broken tap extraction.
I'll check it out, thanks
good video, ta.
I wonder if the sector plates were larger in diameter, if that would reduce error. Great idea! I am going to check out my lathe now for that standoff point. Thanks for putting this together.
Yes I think it would. I’m also thinking about remaking these in metal.
@@joneseymakes I just saw the part two of this project. You got me seriously thinking about doing this
With tapped holes, the maximun strength achieved is 1.5 X screw diameter. With thick parts drill the clearance size hole for 2 to 4 threads, this achieves 3 things, location start for the screw and it gives a nice round hole to countersink and lastly any tendancy for the threads to pull upwards will not interfere with the mating parts. Car cylinder blocks and gearbox housings use this feature so nothing interferes with two flat mating parts. Drill the holes deeper than needed and do not let the tap bottom out. Regards from Australia.
Good shout Dave, I hadn’t thought of doing that before. I’ll be sure to give it a go next time. Cheers.
I was once helped in such a situation on an electrical erosion machine. The remnants of the tap were removed in this way from the blind hole in the aluminum part. Your situation is much simpler, the hole is through.
Good luck!
Thanks!
Very nice job! I'd like to see how well the lines meet up when you do a full revolution. :)
It's always the last hole that breaks the tap, eh? As others have said, alum powder dissolved in water (keep adding powder until it stops dissolving) will get rid of your steel tap without harming the aluminium. Just make sure you use a container that the alum solution won't attack. I've done this before, an aluminium pot is nice because you can heat it slightly on a hob to speed up the reaction. Eventually the tap will turn dark brown or black and start to disintegrate. A bit of wiggling and poking with something should free up the remaining chunks. It can take a while but don't give up, as long as there are bubbles coming from the tap, it's dissolving.
Oh and a note on the alum powder, it should look like tiny crystals. Vaguely translucent if they're big enough, in any case brittle and salt-like. It's also sold under the name "fatakdi powder". You don't want to know how long I spent heating a pot of "alum" powder which turned out to be some sort of insoluble floury substance that did nothing at all to the tap or the aluminium. Thanks eBay.
Thanks for the advice on tap removal, I'll try that. I'll be doing more testing in the next video so full revolution coming up!
Do u know the chemical formula for the alum powder?
@@pinepienaar3401 According to the internet it's KAl(SO4). Potassium aluminium sulphate.
nicely done! in the absence of a band saw, a Dremel Cutoff disc might be a good choice! :) For the tap, you might want to consider building an EDM tap remover and / or use an EZ-Out if the size of the tap allows for it.
Thanks for the tips!
Many years ago I saw a scheme for a military lathe where a indexing head was mounted on the spindle outboard and a powered spindle on the carriage could mill or use a slotter on the work piece.
That sounds interesting, don’t suppose you have any pictures?
@@joneseymakes I wish, it was in 2004 on Aberdeen Proving Ground.
The mill in any case was some incarnation of I believe "Master Mill" where the base and the spindle had a translating screw between them and guided by four guide posts like a die set. The motor was belt driving a worm gear box/spindle. There was also a reciprocating slotter bar attachment where the cutter would pivot in the bar on the retract. I think they were used as part of a very compact repair shop.
Great video. Thanks. I see that when you were hand tapping, you did not use a tap follower in the spindle. I saw the tap bending. Use a cheap spring loaded tap follower to keep the straight.
Thanks. Yes, good advice. I don’t know what I was thinking that day!
nifty idea
Thanks!
Agree on the tapping fluid, always use it and consider it necessary. I think using some cutting fluid on your slitting saw would have allowed it to do deeper cuts too. When using the hack saw on something like that collet, don't try to cut through both sides at the same time, use a shallow angle and watch the material be removed.
For the 3d prints you should have left the sizes close and used a heat gun to heat the surface of the plastic a bit then pushed it on, then it'd be a really tight fit that lasted forever.
You can also use alignment pins instead of so many screws, you can get clever with this using 3d modeling instead of actual pins, or even make the holes the size of filament. Do some experiments with using filament as plastic rivets that you can heat up with a heat gun or iron (not a soldering tip though).
Thanks Justin, great tips. I would do a lot of things differently next time.
Here in oztralia we have a green cutting paste called "trefolex" which is a little messy to deal with but is awesome. I don't know if you can get it in the U.K but its really good stuff and can save a lot of hassle. It melts with the friction of the cutting action and flows down through the cut. I flatly refuse to tap without it.
Great tip! I'll see if I can get some. Cheers.
Vaseline does the same. Been using it for 30 years. Melts in the hole and non toxic, non staining and non stinky.
Available in the UK as well but I prefer Rocol RTD in both semi-solid (looks like grease) and liquid form. It washes out easier, plus I was given a few tins of the RTD semi-solid from an incorrectly picked delivery that someone had from a supplier who did not want it returning.
Cool project. While trouble shooting, you may want to check the steps per millimeter on your 3d printer. If the motors are not properly calibrated the parts will not be perfectly symmetrical.
Thanks Boba, I'll try that.
I believe an alum solution is useful for dissolving broken taps with no damage to the surrounding aluminium. Ive seen it done on forums Im on but no experience myself, may be worth looking into
Great tip, thanks!
ive become pretty good at removing broken taps! #1 omega drill $$$$ #2 carbide endmill $$ #3 a small broken carbide endmill and a hammer and chip it out and i bet you have a broken carbide endmill priceless! lol but those are my methods of madness. ive heard of people disolving the tap in a solution too or just rock it like you have cuz as you said 5 is good enough loved the idea!
Haha! Glad I'm not the only one!
Side comment (and possibly re-stating the obvious) re: 3d print fitment - I've gotten a lot of mileage out of printing smaller, quicker-to-print sections of parts when fitting prototypes, it's the best of both worlds for time and flexibility. Thank for the video!
Great point, something to bear in mind for next time. Thanks.
Get yourself some 'Trefolex' (tapping snot). Works great. And always back off a LOT more than your patience would like.
Remember, Ally is soft and you need big teeth and faster speeds to cut it. Same if you are using a hacksaw (biggest teeth spacing you can get.)
Love your design though! Fantastic stuff!
Will be happy to pay a few bucks for plans/models.
Keep ip the good work mate!
Thanks James, great tips much appreciated. You can buy the plans from Joneseymakes.com
Be sure you back out the frequently when tapping small features. If it starts to get really tight do not go further, back it out slowly. If it gets tight again, screw back in, then slowly back out. Forcing it like you did will ensure a broken tap.
Top tip for 3D printing. Print out the areas that are going to interface with the parts that you need to interface with just the interface area so you can get that size and correct and then print out the whole part
Good thinking. I’ll do that next time
I was going to say fluid lots of it. Nice job and we all have made the same mistake🤩🤩🤩🤩🤩🤩🤩🤩😎😎😎😎😎
I don’t know why I didn’t think of that at the time! Schoolboy error!
Broken tap - I had a similar experience when making a steel backplate. My solution was to anneal the tap in the backplate and once it was softened, drill the tap out using a smaller diameter drill. I was then able to chip bits of tap out of the hole. Annealing obviously discolours the work piece and depends on the work piece being able to withstand the annealing temperature.
Good thinking, never occurred to me that I could anneal it.
I have removed broken taps from aluminum (ONLY Aluminum), with sulfuric acid. works amazingly!!!
That's battery acid, available at the auto parts store.
Thanks, good tip!
I'm thinking of doing something similar, but mounting a rotary table on the back of the spindle, with the internal expanding collet mounted on the table and the rotary table housing stopped from rotating by a long arm attached to the headstock.
Sounds like that could work.
If you break a tap in aluminum, you can often dissolve the tap in sulphuric acid without affecting the aluminum.
Thanks Rod, good tip
When needing a close fit with a 3D printed part, I will model just the section that needs to fit and print 2-3 at slightly different sizes to try out the fit. When I find the one that fits well, I update the actual model to match. Saves printing several complete larger parts.
Thanks for that, good tip.
Hello, what CAD system are you using? I like your video style and that you leave mistakes and solutions in. Great idea, cheers Wylie.
Thanks Wylie, I use Autodesk fusion 360
Mr Pete says you only really need three or four threads and recommends over sizing the hole a bit for a percentage the holes depth so the tap only engages a portion equivalent to a common nut thickness therefore not to overwhelm your tap.
Thanks, good tip.
Wall of text of ideas for ya...
For broken taps i recommend using some oil/cutting fluid when cutting threads in the first place. To get em out again either specialized tools for that or thin pliers and a small hammer. Tap it loose with the hammer and twist it out, compressed air helps to evacuate the chips. In high strenght steel with carbide tooling you might be able to literally break the tool with a hammer and pull out the pieces but your threads gonna be murdered after that so only works when u can add a bigger size thread in the same spot later. Or wire EDM it / make the part again...
Also Your Print at 4:40 -ish seems to be a bit out of whack in the X/Y axis on the printer. Might be warping from thermal stress or your belt tension is off in the X/Y axis. Maybe check belt tension, is a quick and cheap fix if that should be that case (frequency tester app for guitars on phone work wonders, pluck the belt like a guitar string and see how far they off and tighten according (maybe manufacturer even has proper Hz settings at hand). Also for gummy sorts of aluminium (usually containing Si !) WD40 or a light oil as cutting fluid works wonders for surface finnish and sticky chips.
Also really well made video there and i like the design of that indexer. Keep up the good work!
Thanks! Some great info there, really appreciate the tips and advice.
@@joneseymakes Been there done that ^^ Hope it saves you some trouble for the future :)
That’s a fascinating idea, even if the implementation needs tweaking. I suspect the biggest source of error is your 3D prints. I’m now thinking of making something similar, but seeing if I can machine the plates using gear indexing or x-y coordinates. Many thanks and this.
Thanks Mark. I'll see if I can iron out the problems with the 3D prints, if not I'll machine some plates up.
Broken tap, old school, use a carbide drill to cut the web out. New school, use a solenoid and a wire to EDM the web out.
Thanks for the tips
That is a gorgeous surface on that aluminum. What RPM are you running?
1200 rpm
Did you consider if the internal surface of the lathe drive shaft is an accurately milled tube running true!?!? Maybe bore it to be sure.
That's something I didn't consider actually. Thinking about it though, as long as it's not a million miles out I don't think this is too much of an issue. If you think about it - where we need the accuracy is in the angular indexing of the rotation. If the internal bore of the spindle is slightly out of concentric that might affect the alignment of the holes (meaning the pin wouldn't go through) but shouldn't affect the indexing of the rotation.
Hello, your video piqued my curiosity and I will try to make this angular vernier. Do you have examples of uses other than graduations? Thank you for an answer, good continuation good end of the day, cordial greetings. P.K.
If you have a milling attachment for your lathe or a cross slide mounted drill then this attachment can be used to mill hexagons, drill cross holes etc etc
When you designed this did you purposefully design it to be visible from where the camera is positioned? My lathe's design is such that all the parts that are readily accessible in yours are housed inside a metal cabinet on mine. Someone with a similar lathe as mine should redesign the red piece to be larger than the black or brown piece and flip the numbers to the opposite side, but keep the holes exactly where you have them.
This is such a cool idea and I am excited to try and replicate it.
I don't have much space to the left of the machine so I designed it that way around. Ne reason you couldn't do it the other way though I think.
Hi, it's good job👍
Please can you provide us Which designing software you used for this tool?
Thanks! I use Autodedk Fusion 360.
Cool project! But I don't think FDM 3d printer is up to the task with required level of accuracy. Even if everything is well calibrated there is still material shrinkage when plastic is cooling down and it can cause some warping. I'd suggest machining 3d printed parts. Or maybe try 3d print the overall shape and then machine just holes using a DRO? Never seen anyone do something like that but why not :D
You may well end up being right, but I'm interested to find out if the 3D prints will stand up to the job. I need to do some more testing, if they turn out to be inadequate then I'll machine some out of metal.
@nyalith. I have made the missing indexing plates with my Prusa for my emco. 100 micron precision is attainable. The position of indexing holes with a 40 turning of the indexer for one turning of the table is plenty precise. The great advantage of 3D printing is
that it is not time consuming, and you don't risk spoiling the part at the last minute with a mistake.
Never tap aluminum dry and use a tap guide. The easiest way to fix a broken tap is don’t break the tap.
Great content and nicely made.Could some of the error be due to the fact you are indexing from a 3D print? If the bore diameters are undersized and out of round then presumably the locations of the index holes may be off somewhat as well.
Possible I suppose yes, although I think the problem lies elsewhere. I’ll do some more testing. Thanks for the suggestion!
What you need to do with the 3D print is to make a test piece of the correct diameter. That way you'll know what the final size comes out at, it'll depend on your filament, the bed height, the phase of the moon and probably next weeks Lottery numbers. Holes always comes out undersize, but how much is easiest to determine by trial and error.
Once you are happy with your test piece, alter the CAD drawing of the real part to suit. I can usually get it spot on within a couple of iterations now
Good tips, thanks for that.
Hi! When use a tap, specially in aluminum, you must need to add a lubricant, but that lubricant has to be special for "tapping" aluminum and don´t forget, go slow, retract the tap many times and be gentile. Greetings from Costa Rica! 🤣
Thanks for the tips!
Jonesey can you post the manufacturer and part number of the chamfer tool you use on your mill? Thank you.
Hi Stephen, this is what I used;
www.cutwel.co.uk/8mm-4-flute-uncoated-solid-carbide-45-degree-chamfer-mill-cmc100-45-series-cutwel-pro
While the expanding mandrel / petals is a good design, a locking collar that slides over the spindle and the indexing shaft will be simpler and at the same time allow for stock to stick out through the indexing shaft if you want to design it that way. Just an idea.
Hadn't thought of that, good idea.
Definitely start using cutting fluid. You’ll still break taps, cause that’s what taps do, but you’ll definitely go longer before you need to get another one.
Yep, silly error that one. I normally use cutting fluid.
I've had to remove taps from valuable parts before. Usually what I do is get a carbide end mill that is the size of the drill hole (smaller than the threads). Then set the spindle speed to about twice what you would normally run it. Use cutting oil or coolant to keep the end mill cool. Then you feather it in as gently as possible (.001-.003 of an inch at a time). It will be time consuming. It is the ultimate test of patience when it comes to machining but just go slow. The carbide end mill is trying to chew threw steel that is only slightly less hard. Listen for any crunching or snapping. Check the end mill occasionally. Keep dabbing it with oil or coolant. If everything goes right, the tap will basically be reduced to metal chips and will no longer be stuck in the hole. Don't know if you have access to carbide tooling but that's how I typically get broken taps out of parts that have a lot of time and effort invested in them.
Thanks for the advice!
I know this is a little late, but to remove taps like that, I usually “drill” it out with a carbide endmill that’s the same size or smaller then the tap drill size. Then the rest usually breaks free. Every once in a while if it’s a really brittle tap you can hit it with a punch and break it out in pieces.
Thanks for the advice!
I plan on doing your mandrel but attaching it to a 6cm 180 tooth cog belt with a 12mm 12tooth idler and a stepper motor. Thanks.👍🖖😇,jpk
Sounds awesome, good luck!
14:03 Hacksaw hacks... When hacksawing point your index finger straight ahead alongside the handle. This can help keep your saw strokes straighter provided your hacksaw blade is sharp and has an even bite. A little WD or other fluid is useful to keep the aluminium from sticking to your teeth.
Thanks for the tip!
use good carbide end mill but center out then take punch chip out
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@@Myledailuon79 Nghe có vẻ thú vị!
the small error might come from you reaming the holes? think you should've modified the pin to fit the holes... besides that, marvelous work! I have to make one like it
Being a 3D print each of the holes were slightly different so the best course of action was to ream them all to the same diameter. I'll do a follow up video on de-bugging the issues in accuracy
i would like to build one just for fun, my lathe has an MT5 taper on the back so my expander would need to be much longer to reach flat shaft
I’m going to re-think the design to accommodate different shaft types.
Are you assuming the spindle bore is smooth and concentric with the rotation axis? Because is not usually
Well mine is more or less, not sure about other lathes.
@@joneseymakes Oh ok. Mine is not because I was thinking to do the same as you. I have an alu pulley on the spindle so I think I'll put a spacer on that and mount the dividing disk on the spacer and the spacer on the pulley. What I don't like is there could be (did not measured yet) a play between the pulley and the spindle even with a keyway