New acme nut for my mill.

[Terry Keeley]

Thanks guys, I'm learning.

I joke with my toolmaker buddy Rudy all the time, "we're not gonna make any money on this job but the customer's sure gonna be happy".

It usually takes me 2 days to do what he would do in an afternoon.

 

[Brad Christy]

John, Dave,

My ProtoTrak does this technique beautifully. CNC turning centers do as well. Humans do not. We are not nearly as consistent as machines are. That "same place every time" thing is just not in our wheelhouse. And this becomes a problem. The first couple times I tried threading on a Hardinge, I was taught to use the compound retract lever. What inevitably happens is a late withdrawal of the threader, digging into material that it just doesn't stand a chance of cutting, breaking the threader. I'll take an undercut over a "pigtail" any day. Besides, any sharp inside corner is a crack origin waiting to happen. An undercut eliminates this altogether, where a "pigtail" leaves it. The next time you see a threaded part break, be it a screw or whatever, look closely and you'll see that the break started at this pigtail. I've been part of many "stress to fail" studies. A well designed undercut, with proper radii, is, by far, stronger than the pigtailed thread. I've seen undercut sections stretch well beyond where a non-undercut threaded part had failed: same material, same thread.

Thanks. Brad.
Titan Racing Components
BlackJack Hydros
Model Machine and Precision LLC

 

[dwilfong]

O and don't spin it to far so you do not bottom out the dial indicator.............

 

[John Beardslee]

Brad,
No doubt about it, CNC machines are far superior to humans in all facets of machining. Dr. Rex Hall (Western Michigan University Professor) and I we the first two educators to go through Cincinnati Milicron CNC training back in the “Flex Tape” days. Care to venture the year?
Part of the reason for pig tailing external threads was to have the student machinist develop better eye hand skills and better understanding the machine. At the time it was the accepted industry standard.
Many of our hobbyist don’t have access to CNC equipment and use or abuse older manual machines. Most can access videos on YouTube but it’s nice to have first hand verbal instruction via a mentor. In some areas there are local machine shop clubs that have machinery and instruction available.
Thanks, John

 

[dwilfong]

The best lesson was wearing the chuck key around your neck all day....................................................
Me mixing it up with the crew......................