Setting my boring bar

[Makintrax73]

I get the idea that these little lathes prefer HSS tooling, I have heard that before. I looked for premade HSS boring bars, but did not find one. Could I buy a piece of drill rod, heat it red, and then give it a little bend, and grind off what I do not need? I am not concerned about that part of the process, but a bit unsure about sharpening...... Would I need to harden drill rod after I heat it red hot? I have a temperature controlled kiln, and I also know how to use color to temper, do I have options there.

What would it take to sharpen a carbide boring bar? Could I do that with my standard bench grinder, or do I need a special wheel?

Richard

Here is the set i bought that has a small boring bar. https://www.amazon.com/AccusizeTools-Pre-Ground-Turning-Aluminum-Steel-2662-2004/dp/B0779JX3GH/ref=sr_1_5?crid=1TCL97NB42U7O&dib=eyJ2IjoiMSJ9.u8ru3EPSgyHTfyx0J6ttIBGRhmEUUWUcl-NMg9rDll6SWchaS-0VLfV56dxpRmDA1s-dm6Af3jOsl6zxlDM-U7KtxH99nKkcPih2PIpoJLWS_G4FSoxqrrpVZa1TUBvjXN_TQwyxdj-nFaWN3NRReheqp9WBDrp4bUAyHqKFRSyWG_scob80gTUuUMEX_AV7dH2W3-UmherrzrcOeAX1DUnZ8rNHF_QIZd2hLh_baAw.Ezm9oWt1eDZt18vOtjyOXQLgrUvOwfGe8dZWRRdNIqk&dib_tag=se&keywords=accusize+boring+hss&qid=1715166431&sprefix=accusize+boring+hss,aps,178&sr=8-5&th=1

You absolutely can make custom tools from tool steel and then heat treat. But it's not going to work as well as HSS, so in this case i think there's a better way to skin that cat. Basically you use W1 or O1 (water or oil hardening) tool steel. Shape or cut it. Heat to cherry red, then quench in either water or oil.

There really is a lot of leeway in grinding your own tooling from HSS. You have to have it sharp, and you have to have clearance angles. Beyond that the rules are really more like guidelines than anything. So don't be afraid of that. A 1/8x1/4 hss blank is dirt cheap, and a steel rod is dirt cheap, which is why I recommend welding or brazing these together to make your own.

Yes you need a special wheel for carbide. I dont have one. I have managed to shape carbide with diamond coated grinding bits chucked in a drill press and finished with a diamond lap. Really not ideal, but more or less worked.

Examples. Accusize pre-made tool which I subsequently ground for more clearance on some job. A welded hss boring bar. A 1/2 boring bar with a broached hole and 1/4" hss bit. They are all ugly as sin but they will bore a hole and make a chip.

 

[RaisedByWolves]

And here I thought I was nuts for using my boring bars like that...

Standard procedure.

No matter how sharp your cutting surface is it’s still going to have some what of a “face”.

Raising the tool a little helps prevent the chin portion of the face from rubbing and preventing good cutting action.

 

[GrifterGuru]

Standard procedure.

No matter how sharp your cutting surface is it’s still going to have some what of a “face”.

Raising the tool a little helps prevent the chin portion of the face from rubbing and preventing good cutting action.

I am aware of rubbing the bore with the "chin" as you put it, hence why I went the "slightly high" tool height route for boring bars.

I just thought it was wrong, I was nuts for doing that even though it worked, that I was using the wrong size boring bar for the bore I was machining and potentially heading into a world of problems.

 

[benmychree]

Using a tool steel such as 0-1 or W-1 for a boring tool is not a particularly good idea because it does not result in a tool that can be run at higher speeds such as mini lathes exhibit, a tool bought in HSS or one ground from a square tool bit would be a much better tool, as stated by me a number of times on this forum, okum boring tools a better in every way than kluged up home made tools, they come in several styles and sizes and are worth a look, they are fairly often seen on E Bay for sale used.

 

[RaisedByWolves]

Using a tool steel such as 0-1 or W-1 for a boring tool is not a particularly good idea because it does not result in a tool that can be run at higher speeds such as mini lathes exhibit, a tool bought in HSS or one ground from a square tool bit would be a much better tool, as stated by me a number of times on this forum, okum boring tools a better in every way than kluged up home made tools, they come in several styles and sizes and are worth a look, they are fairly often seen on E Bay for sale used.

I've used both broken and complete endmills as boring tools before with good success.

These can be ground to a profile of your choosing or used as is, and its a great repurpose of an endmill with a broken flute.

I use them in boring heads also and the best part is they flex very little compared to some off the shelf bars available.

 

[benmychree]

When it comes to flex, consider that there almost no difference in deflection between soft steel, carbon or alloy steel in terms of deflection under load, this goes to Modulus of Elasticity. The only difference is between steel in all its forms and carbide, which is much stiffer.

 

[RaisedByWolves]

For a solid bar of the exact same shape and size, no.

We’re not talking about a solid bar though.

 

[raferguson]

I ground my boring bar with my aluminum oxide grinding wheel. I think that perhaps the boring bar was rubbing against the work, and it just needed more overhang. (Not sure of the technical term.). Seems to work reasonably well now, the chips show some curl. I seem to be able to make 0.003 inch passes. Thanks to all for their comments.