2016 POTD Thread Archive

[great white]

I wonder if he did something custom.

I'll be making a "schaublin" style collar for use with my next backing plate on my Atlas to keep the chuck from turning off in reverse.

Looks like this:





My issue is going to be cutting the threads. I haven't cut any threads at all on the lathe as of yet.

Gonna have to figure it out though. I need to cut metric threads and from what I understand, I'll need to run the lathe in reverse in order not to mess up metric threads....

 

[chevydyl]

Me too, I know on my 4 jaw chuck there is room to drill and tap for these keepers but my 3jaw is hub less

 

[chevydyl]

Great white, you will have to run in reverse but only to back up, not to do any cutting

 

[gjmontll]

If you've brought O1 up high enough in temperature (i.e. bright red) the hardening happens with a rapid cool down. Since your parts are so small, they likely hardened due to their size and speed of cooling. At this point, they are likely too hard unless you have tempered them slightly. O1 is not a very good steel but has its uses and when too hard, it is very brittle. Bring it back up to 500-600F to temper it back a bit. If you polish it, this is a slight tan/straw color when heating. Since it is so small, you will have to be very careful or you will bring it dead soft again.

Thanks for the analysis and advice, Techie1961. So it air-hardened; what's more, immediately pushing the bolt head into the hot zone would accelerated the cooling. I will temper the tools as you suggest.
For these small fasteners, not much torque is needed. I would have used mild steel but didn't have a proper diameter in my stock pile. That's why I used the drill rod.
Greg

 

[markknx]

Chevdyl, the keepers (lack of a better term) attach to the chuck mounting plate with a socket cap screw. the head side end has a beveled finger that grabs a flange/groove on the spindle. They have to be removed before the chuck can be unscrewed. here is a photo as I am not always the best at describing things.


But as I said even with this I do not think it is worth the risk. Would this hold? probably, will I risk it? not likely. Your point was well taken.

Mark

 

[chevydyl]

It actually looks like those are there to prevent unthreading the chuck while running in reverse, your probably ok

 

[markknx]

It actually looks like those are there to prevent unthreading the chuck while running in reverse, your probably ok

Yes that is no doubt what they are for. but it is a Chinese Lath so I think I will stay away from that also as brought up the lift on the cross slide and saddle may also be bad.

Mark

 

[great white]

Chevdyl, the keepers (lack of a better term) attach to the chuck mounting plate with a socket cap screw. the head side end has a beveled finger that grabs a flange/groove on the spindle. They have to be removed before the chuck can be unscrewed. here is a photo as I am not always the best at describing things.
View attachment 118474

But as I said even with this I do not think it is worth the risk. Would this hold? probably, will I risk it? not likely. Your point was well taken.

Mark

While I am no expert, I have been told that type of arrangement is to retain a threaded chuck when sudden stopping or reversing.

Great white, you will have to run in reverse but only to back up, not to do any cutting

Yep, back it out of the threads too as I understand it so the backlash in the half nuts doesn't mess up the threads on the way back out.

I've also been told by a couple machinists at work that reverse is very useful when cutting lands inside a cylinder (IE: o-rings, snap rings, etc) as you can actually see what you're doing from the normal "in front" standing position.

They've told me a few other things that can be done while reversing (like certain types of chamfers and whatnot) but most of it went over my head at the time....

 

[WMello]

My attempt at cutting bevel gears




Wagner

 

[Cheeseking]

Wow cutting gears is very impressive. I always wonder how its done to where when you get all the way around to the first tooth, the spacing is dead on. I mean if you are off a little bit each tooth will it accumulate and end up with a big fat or really skinny tooth?
Almost embarrassed to post my wimpy little project now which was to make a chip shield for the 1100 vise from this pc of plastic I found.



The foam board actually worked pretty good as a sacrificial backer. The clamps bowed the acrylic a bit but it was solid enough to do the job.