Turning Tool And Facing Tool Questions

JR49 said:
Round in Circles, not sure if I'm understanding correctly, but if I am, you can grind the 1/2 " tool so that it will go straight in like a boring bar. If you cut the little parting tool at the front perfectly perpendicular to the tool bit then, just be sure that the tool is parallel with lathe axis, and the groove will have a 90 deg. face. See my sketch, hope this helps, JR49View attachment 109133
EDIT, if you have a boring bar that holds a 1/4" or smaller bit at 90* to the bar, you can use that and have less grinding. good luck
Click to expand...

He is asking the best way to clean up a shoulder cut after drilling and boring. Your bit design would work fine. He would need to set the depth either with a stop or indicator. In your drawing you show a undercut so there will not be any question the shoulder is sharp and clean. He should grind the the clearance area behind the cutting area so the bit can be used on deeper shoulders.
 
I decided to grind a Square Tool to show how it looks. This is a 3/8" HSS bit from Japan and it is quite a good blank. As you may recall, my Square Tool is ground with 15 degree relief and rake angles and will do a decent job on most common materials we find in a hobby shop. This one has a 1/32" nose radius on it. All grinding was done on my belt sander with a 24 grit AO belt.

This is the ground tool from the side. Note that the tip is at the same height as the shank of the tool, which means the grind extends all the way to the tip ... but no more.

CRW_4592.jpg

This is the top surface of the tool before honing.

IMG_4586.jpg

This is the side after honing.

IMG_4601.jpg

The top.

IMG_4642.jpg

The end.
IMG_4646.jpg

And an oblique view.

IMG_4644.jpg

The tool is honed with diamond stones and the nose radius is then stoned to shape and blended with the side and end faces. It is razor sharp and the tool cuts very well.
 
mikey said:
I decided to grind a Square Tool to show how it looks. This is a 3/8" HSS bit from Japan and it is quite a good blank. As you may recall, my Square Tool is ground with 15 degree relief and rake angles and will do a decent job on most common materials we find in a hobby shop. This one has a 1/32" nose radius on it. All grinding was done on my belt sander with a 24 grit AO belt.

This is the ground tool from the side. Note that the tip is at the same height as the shank of the tool, which means the grind extends all the way to the tip ... but no more.

View attachment 111286

This is the top surface of the tool before honing.

View attachment 111287

This is the side after honing.

View attachment 111288

The top.

View attachment 111289

The end.
View attachment 111290

And an oblique view.

View attachment 111291

The tool is honed with diamond stones and the nose radius is then stoned to shape and blended with the side and end faces. It is razor sharp and the tool cuts very well.
Click to expand...

Nice job of design and grinding
 
Great job, Mike! These pics are going on file with your grinding posts that I have saved. You must have been a teacher in another life. JR49
 
Maybe the management of the site could make Mike's photos and write up a sticky in this section, so that folks can easily find it to refer back to it.

Great photos!!!
michael
 
Thanks for your kind words, Guys - I appreciate it. I hope the pics show the various angles so folks have a better idea of what we've been talking about here. It isn't as good as a tool-in-the-hand like Mark was talking about but its better than nothing.

As I was grinding the tool above the belt snapped at the splice and I swear I must have jumped about 4 feet in the air! It happened just as I was completing the rake grind on top of the tool so I was standing very close to the belt and ... POOWWW! I had a replacement belt but it was from the same lot as the one that snapped so getting up close to it to finish the tool took some nerve, but I did it. Then I went and washed my shorts!
 
Nice Mikey, Sorry I did not get back to you earlier. Yes the offer was a good one and like others I think your work should be posted some place easy to find for guys trying to get a grip on grinding. Or even improve their skills. Like me I'm never against learning new ways of doing things.
 
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markknx said:
Nice Mikey, Sorry I did not get back to you earlier. Yes the offer was a good one and like others I think your work should be posted some place easy to find for guys trying to get a grip on grinding. Or even improve their skills. Like me I'm never against learning new ways of doing things.
Click to expand...

Thank you, Mark. My offer to do a tutorial/pictorial stands if there is any interest.
 
Thanks Mikey and everyone, the pics are great and will definitely give me a good example of what to shoot for when grinding my own tooling.

I agree this post should be turned into a sticky in the Beginner's forum.

Joe
 
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