Lathe boring

[snoopdog]

So, I picked up a r8 end mill holder the other day and want to enlarge the ID by .250, to 1.25 . The OD is 2.25, my concern is the interrupted cut where the set screws are, I don't want to crash my welded carbide boring bar and I don't have a hss one. Any suggestions for using carbide on interruptrd cuts like this, or even an outside turning operation such as hex? TIA

 

[Technical Ted]

I would suggest buying a holder the correct size. It might be too hard to cut, especially with HSS. If you are determined to try, use your carbide bar using very light cuts. Good luck...

Ted

 

[mmcmdl]

I would suggest buying a holder the correct size.

I'll second that . They are hardened and you also want as little TIR as possible .

 

[Charles scozzari]

I agree, Buy the correct size holder. I've attempted to resize a holder and it was not worth the effort when the right size holder is available.

 

[MrWhoopee]

Agree with the others regarding modification. Re: the original question, put sacrificial set-screws in the holes to eliminate most of the interruption.
Bore with carbide, it's going to be hard.

 

[Charles scozzari]

Agree with the others regarding modification. Re: the original question, put sacrificial set-screws in the holes to eliminate most of the interruption.
Bore with carbide, it's going to be hard.

That works very well.

 

[mattthemuppet2]

I'd personally question the wisdom of using a 1 1/4" endmill in a machine with an R8 taper. I think 3/4" is the limit to have the tool shank within the spindle, everything above that the top end of the tool is outside the the spindle. That's alot of leverage for a large cutter. At least you're using a holder and not a collet, but you'll still struggle to use that cutter for side cutting.

What do you need to run and is there an alternative we can think of?

 

[Charles scozzari]

I'd personally question the wisdom of using a 1 1/4" endmill in a machine with an R8 taper. I think 3/4" is the limit to have the tool shank within the spindle, everything above that the top end of the tool is outside the the spindle. That's alot of leverage for a large cutter. At least you're using a holder and not a collet, but you'll still struggle to use that cutter for side cutting.

What do you need to run and is there an alternative we can think of?

Hi, I don't know what the intentions or use for a 1. 25 r8 holder would be, and 3/4" is also my max. But I like to make purpose built tooling and I'm sure this falls into that category. Home shops sometimes have to get creative and work with what we have on hand. I think that's how this whole thing evolved into what we enjoy tinkering with today. As for an optional set up, I'd interference fit a 3" round stock of steel over a r8 holder lock it through the set screws in the r8 tool then bore it to 1.25 as my photo suggests. Take the O.D. to what you like. Thank's, Charlie

 

[tq60]

We got a steal deal on batch of tooling, a handful of 1 inch shanks.

Quite a few holders on Amazonfor maybe 30 dollar range.

There are a few 1.250 units, price not bad, not worth trouble to modify something as the source is no longer available.

Sent from my SM-G781V using Tapatalk

 

[snoopdog]

Thank you for all the responses , and explanations. I've decided to 86 the idea, it was a frivolous one to use some cutters, possibly in the future that certainly dont match the horsepower of the mill that I have. I bought the holder at a flea market for 10bucks and have some bigger cutters, (my trading post, post) that aren't really usable and I just thought if I could use them in some capacity, then I would. Thanks again.