The way to go Ralfy. I made mine out of an old railway track dog plate, but you could use anything that was thick enough to give a good parallel grip. Easy to make. Cheers Rob
Super useful as my blunt drills bring forth bad words & slow miserable times & this gives a way that is repeatable to have a factory edge that makes drilling a pleasure. Almost worth upgrading from my air dye grinder just for this capability. Thanks for sharing!
From memory we used to grind drills to 118 deg included for use on steel. That looks like a great technique to get both sides even. Too much clearance will weaken the edge and make it chip more easily. I remember sharpening a 3” drill by hand once. Took me ages to get it right. Thanks for sharing
From a toolmaker's perspective this method is great ! Sharpening by hand is the same exact theoretical part as this method. So all that is needed now is the PRACTICE of holding the thing in front of any grinding wheel; without the all the fuss eh... ÜïÖ
Yes, totally agree. I was taught to sharpen all my drills by hand, by my mechanic father. BUT, you will never get the flutes as evenly ground compared to a rigid grinder setup. I generally only use the TPG when the tip angle gets badly out of whack. Cheers Rob
Great tip there rob. I have used a similar method to re-profile drills using the flat face of a small stone. Only works on small drill bits under about 4mm, but these are the hardest to sharpen evenly I find. Going to try out your method in the future!
great trick! can we grind the saw blade carbide teeth? I have many ATB (Alternate Top Bevel) saw blades of various thicknesses, and I'd like to use them as Dado blades, but it results in the grove / rebate / dado being very uneven. I wonder if we can flatten the saw blade teeth by grinding them
@@Xynudu that's some great news. I believe with the blade in the lathe, and Hilda in tool post, I can get pretty good accuracy and repeatibility I look forward to checking it out
Rob, Wow! The first comment! A pretty nifty trick for grinding drill bits. I've tried to do the job by hand with a bench grinder and usually end in disaster! I was given a supposed "super nifty" drill grinding machine. Like you, I haven't had much luck with it. (Thank God I didn't pay for it!) Anyway, thanks for the tip. Have a good one! Dave
Hi Dave, I usually grind them by hand. Quite OK. My father was a motor mechanic and they all did it by hand, and I was taught how. It's not that difficult, but you never get the same level of accuracy as a proper tool grinding machine. This does a good job at cleaning up hand grinding and touching up edges. Cheers Rob
Hi Dave, This gives a similar finish/cutting edge to those straight cut drills you have. The main thing is to have the edge of both flutes horizontal/90 degrees to the grinding wheel, otherwise one flute will cut more than the other. You can actually/also raise the grinding disc above centre line and sharpen the flute nearest the operator, but it's more difficult to see, to align the flute edge horizontal. It is easier in that you can just shim up the tool post holder to raise the grinder. Of course anyone with a QCTP will have no issues either way. Cheers Rob
I think the fiber reinforcement of these cutoff discs means that pieces of the disk breaking off get spun around carving out irregular gouges in the metal. This seems to happen no matter how light a cut you take. I think a better cut made by a smaller wheel would probably last longer despite the increased concavity. Did you try the angle grinder wheels? It might also help to burnish the cutting edges to remove the burr.
The grinding marks don't really matter, much the same as for roughing up end mills. You can use a normal wide grinding stone with the feed method shown, or by setting the carriage stop and driving the wheel against the full edge of the cutting flute. This requires a dressed stone. Both methods work fine. The main thing is to have the edge of both flutes horizontal/90 degrees to the grinding wheel, otherwise one flute will cut more than the other. Cheers Rob
Did the cutting disc decrease in size much? If it did, the cutting edges would be offset. I'm guessing not reduction in dia enough to cause noticeable issues in cutting in a drill press, but maybe enough that you would notice in a mill.
No. These discs are very hard wearing and the flutes are relatively short and lightly ground. The main thing is to have the edge of both flutes horizontal/90 degrees to the grinding wheel, otherwise one flute will cut more than the other. This will have far greater effect than disc wear. Cheers Rob
I'm no expert, but I understand it depends upon what you are drilling. Wider angle for hard steel is generally the go, particularly with larger sizes where you will be opening out a pilot hole. From my experience if you use a narrow angle tip in that situation the drill will go blunt quicker and cut poorly as less section of the flute is in contact with the work (for steel thickness as shown in the demo). There are tables for drill point angle you can consult. Also depends on the drill speed. Electric drills made for steel generally spin less than 1K rpm. Cheers Rob
Hi David. I use Smith and Arrow discs : www.smithandarrow.com.au/product/cutting-discs-wheels/3-75mm/3-75mm-x-10mm-bore/metal-cutting-discs-3-75mm-angle-grinder/ I see they sell on Ebay as well. You can only buy these in bulk. I haven't tried to buy from local suppliers. A box of 25 lasts a very long time. I see they are currently sold out of the 0.8 mm discs (very popular). The quality is excellent. Cheers Rob
G'day Rob, a different approach to using the lathe and tool post grinder, well done. You do need a overhead or from the back camera mount or can you mount it off your light arm?? Future project maybe. Thanks Peter
They make TPG's for use on lathes. Maybe visit a machine shop some time and see what really goes on. TPG's are often the only way to machine and fine finish hard metals. Rob
Excellent! This is one of the most practical and usable machining video I've seen in the last 12 months. Thanks.
Happy New Year Rob. Thank you for all the great advice.
Happy New Year to you as well Bruce. Have a great new year. Cheers Rob
Only just caught this Rob, just making a tool post holder for my die grinder, thanks for sharing buddy
The way to go Ralfy. I made mine out of an old railway track dog plate, but you could use anything that was thick enough to give a good parallel grip. Easy to make. Cheers Rob
Love seeing out of the box simplistic thinking. Excellent video Rob
Super useful as my blunt drills bring forth bad words & slow miserable times & this gives a way that is repeatable to have a factory edge that makes drilling a pleasure. Almost worth upgrading from my air dye grinder just for this capability. Thanks for sharing!
From memory we used to grind drills to 118 deg included for use on steel.
That looks like a great technique to get both sides even. Too much clearance will weaken the edge and make it chip more easily.
I remember sharpening a 3” drill by hand once. Took me ages to get it right.
Thanks for sharing
Outstanding Rob! I’m learning so much from your channel 👍❤️😊
Another great video Rob but way above my pay grade. I need to watch it 2-3 more times before I can get my tiny mind around it. Thanks!
Hi Ron,
Think of it as how you would sharpen a flat wood chisel on a round grindstone. Same geometry and effect.
Cheers Rob
From a toolmaker's perspective this method is great !
Sharpening by hand is the same exact theoretical part as this method.
So all that is needed now is the PRACTICE of holding the thing in front of any
grinding wheel; without the all the fuss eh... ÜïÖ
Yes, totally agree.
I was taught to sharpen all my drills by hand, by my mechanic father. BUT, you will never get the flutes as evenly ground compared to a rigid grinder setup.
I generally only use the TPG when the tip angle gets badly out of whack.
Cheers Rob
Great tip there rob. I have used a similar method to re-profile drills using the flat face of a small stone. Only works on small drill bits under about 4mm, but these are the hardest to sharpen evenly I find. Going to try out your method in the future!
great trick!
can we grind the saw blade carbide teeth?
I have many ATB (Alternate Top Bevel) saw blades of various thicknesses, and I'd like to use them as Dado blades, but it results in the grove / rebate / dado being very uneven.
I wonder if we can flatten the saw blade teeth by grinding them
I expect so, provided you index the teeth to get the same grinding position and allow for grinding medium wear. Cheers Rob
@@Xynudu that's some great news.
I believe with the blade in the lathe, and Hilda in tool post, I can get pretty good accuracy and repeatibility
I look forward to checking it out
Rob,
Wow! The first comment!
A pretty nifty trick for grinding drill bits. I've tried to do the job by hand with a bench grinder and usually end in disaster! I was given a supposed "super nifty" drill grinding machine. Like you, I haven't had much luck with it. (Thank God I didn't pay for it!) Anyway, thanks for the tip.
Have a good one!
Dave
Hi Dave,
I usually grind them by hand. Quite OK. My father was a motor mechanic and they all did it by hand, and I was taught how. It's not that difficult, but you never get the same level of accuracy as a proper tool grinding machine.
This does a good job at cleaning up hand grinding and touching up edges.
Cheers Rob
Still got your nose to the old grindstone. Thanks for the video.
I have often thought about if a TPG would work for that....I need to make one
Very novel approach Rob - I shall have to try this out! :)
Can you also create back relief using the grinder set to a different angle?
Please clarify how you would do this.
@@Xynudu It was a question not a statement.
Unless you describe the envisaged process I can't comment.
What a great idea! I have a 3/4 bit in bad shape and I'm not about to free hand it...
Hi Dave,
This gives a similar finish/cutting edge to those straight cut drills you have.
The main thing is to have the edge of both flutes horizontal/90 degrees to the grinding wheel, otherwise one flute will cut more than the other.
You can actually/also raise the grinding disc above centre line and sharpen the flute nearest the operator, but it's more difficult to see, to align the flute edge horizontal. It is easier in that you can just shim up the tool post holder to raise the grinder. Of course anyone with a QCTP will have no issues either way.
Cheers Rob
G'day Rob very good blog mate, it will be helpful regards John.
not bad Rob she does a fine sharpening !
Better than you will get freehand.
Cheers Rob
I think the fiber reinforcement of these cutoff discs means that pieces of the disk breaking off get spun around carving out irregular gouges in the metal. This seems to happen no matter how light a cut you take. I think a better cut made by a smaller wheel would probably last longer despite the increased concavity. Did you try the angle grinder wheels? It might also help to burnish the cutting edges to remove the burr.
The grinding marks don't really matter, much the same as for roughing up end mills.
You can use a normal wide grinding stone with the feed method shown, or by setting the carriage stop and driving the wheel against the full edge of the cutting flute. This requires a dressed stone. Both methods work fine.
The main thing is to have the edge of both flutes horizontal/90 degrees to the grinding wheel, otherwise one flute will cut more than the other.
Cheers Rob
Did the cutting disc decrease in size much? If it did, the cutting edges would be offset. I'm guessing not reduction in dia enough to cause noticeable issues in cutting in a drill press, but maybe enough that you would notice in a mill.
No. These discs are very hard wearing and the flutes are relatively short and lightly ground.
The main thing is to have the edge of both flutes horizontal/90 degrees to the grinding wheel, otherwise one flute will cut more than the other. This will have far greater effect than disc wear.
Cheers Rob
Great explanation--Thanks! I should be able to do the same thing with my RotoZip TPG.
nice video Rob, thank you ,well done....
Clever Rob, thanks! Cheers, Doug
Hi Rob,
With drill bit this size would it be better to have less angle?
I find the Sutton Viper range which is 118 degrees is great for multi purpose.
I'm no expert, but I understand it depends upon what you are drilling.
Wider angle for hard steel is generally the go, particularly with larger sizes where you will be opening out a pilot hole. From my experience if you use a narrow angle tip in that situation the drill will go blunt quicker and cut poorly as less section of the flute is in contact with the work (for steel thickness as shown in the demo).
There are tables for drill point angle you can consult.
Also depends on the drill speed. Electric drills made for steel generally spin less than 1K rpm.
Cheers Rob
Drop dead legs
Rob, where do you get your 75mm grinding discs from. I'm in Tassie, can't seem to find any but bulk (25+) on the web.
Hi David. I use Smith and Arrow discs : www.smithandarrow.com.au/product/cutting-discs-wheels/3-75mm/3-75mm-x-10mm-bore/metal-cutting-discs-3-75mm-angle-grinder/
I see they sell on Ebay as well. You can only buy these in bulk. I haven't tried to buy from local suppliers.
A box of 25 lasts a very long time. I see they are currently sold out of the 0.8 mm discs (very popular).
The quality is excellent.
Cheers Rob
@@Xynudu Thanks Rob.
G'day Rob, a different approach to using the lathe and tool post grinder, well done. You do need a overhead or from the back camera mount or can you mount it off your light arm?? Future project maybe. Thanks Peter
Hi Peter,
I have a rear of lathe camera mount and I've used many times, but with grinders you have to keep out of the line of fire.
Cheers Rob
Seriously I've seen drill bit grinders for 600-800Eur those suppose to grind your lathe bits too.
Never use abrasives near the lathe.
They make TPG's for use on lathes. Maybe visit a machine shop some time and see what really goes on.
TPG's are often the only way to machine and fine finish hard metals.
Rob
I agree with what you said, but then proper way is you have to use coolant to wash away the abrasives as you are grinding.
Very very "un orthodox" way of bit sharpening ! ! !
With the camera angle where it is I couldn't see what you were doing with the grinder. You lost me.
Seems clear and straightforward enough, but I would have to practice, practice, practice, to be confident, thanks for sharing .