Made Some "Big" Threads

[Kevin T]

Just finished up some big, to me, threads to use as a go/no-go on my next project. 2 3/8-6 to match the spindle thread on my lathe. I plan on making a new spindle collar for use with collets.

Until I am better, could be never, at using the machinists handbook to understand all the ways to measure threads I feel much better having a test thread in hand to check for fit.

I didn't respect the extra forces involved in cutting this large of a thread and ended up breaking the Aloris insert! Nice 52 dollar mistake. Sort of lucky that I am on a belt driven lathe too! Got a little slip in the second and a half reaction to shutting her down!

Turned out real nice though!



Next to the beat up spindle collar



Test Fit

 

[Flyinfool]

Looks good.
Yes big threads can generate a lot of force. Have to use a lot of shallow passes to get there.

I like those steel toe flip flops....

 

[Kevin T]

Looks good.
Yes big threads can generate a lot of force. Have to use a lot of shallow passes to get there.

I like those steel toe flip flops....

Slippahs my man!

True about the shallow passes! My ten thou, as read on compound, usual passes were making big hot chips that burned my feet! ;-)

 

[Flyinfool]

.010 on the compound usually means .020 on the Dia. That is a heavy pass for a forming tool.
.010 on the cross slide usually means .010 on the dia or .005 per side.

 

[rock_breaker]

Nice Job, hope the spindle collar turns out as well.

If you were making that in this area you may have brought on some much needed rain.

Have a good day
Ray

 

[jwmay]

.010 on the compound usually means .020 on the Dia. That is a heavy pass for a forming tool.
.010 on the cross slide usually means .010 on the dia or .005 per side.

I think if he had the compound set over at 30 degrees (typical for threading), .010" on the compound is .005" off the diameter. Actually I already think I'm wrong about that.

 

[Kevin T]

I think if he had the compound set over at 30 degrees (typical for threading), .010" on the compound is .005" off the diameter. Actually I already think I'm wrong about that.

Yes, compound set to thread at 29 1/2 deg so it's less than the direct read measurement. I forget the math so I rely on that test thread! lol

 

[benmychree]

I make gages for fitting chuck backplates, and measure the spindle thread with wires or a thread mike and make the gage right on size, I form a knurled handle on them, it reduces weight and provides grip. I see your picture of the tool, same as what I use, when they get ground down from repeated sharpening, I taper them back at an angle as far as the angled mounting surface, this gives much better visibility of the tool point.
I have always set the compound at 30 degrees, and all the journeymen I worked with did likewise.

 

[jwmay]

Oh and also I forgot to mention, Good Job! Looks great!

 

[Flyinfool]

The math is that with the compound at 30°, .010 on the compound will move the tool in .00866 or .0173 on the dia.
29.5° in not much different at .00870 tool movement, or .0174 on the dia. Either way still a lot more than the cross slide.