Tales of Woe!

[sautewes]

I just posted the following on the Live Steam Market Board. Although I did get welcome comments there, I thought it was the wrong place to put it.

I gave up! Thanks to all who took the time to address my problem. I went over all the comments to see if I may have missed something. All the possible glitches were covered. For my last attempt I put a brand new, USA made die on my lathe chuck. I put a heavy duty drill chuck on the tail stock. Next, a clean length of 1/4" crs rod in the drill chuck. I moved the tail stock left towards the lathe chuck, making sure I did not lock the tail stock to the lathe bed rails. Finally, I disengaged the Lathe motor and turned the lathe chuck, buy hand, counterclockwise with proper reversing to break the chips. Turning the lathe chuck by hand once the die had engaged the rod was very very hard to do. I did use cutting oil, of course but that made little difference. I got about 3/4 of an inch of thread on the rod before it was evident the tail stock was hanging up on the lathe bed and wouldn't slide on its own to the left as the rod was pulled into the thread die, resulting in thread stripping. I said, *#!?!!&, this is nuts! I called MSC and ordered a length of 1/4-28 stainless steel threaded rod which arrived the next day.
Wes

I was wondering: Did I give up too easily! As an after thought, it might have been a way to go but only if my lathe had jogging capability. Mine doesn't. Its slowest RPM is 620. I'll bet the sudden start of the lathe would shear that rod clean off. Am I right? I sure don't want to try it!
Wes


0

[FLSTEAM]

Wes

My first question is did you use threading die ( split ) or a rethreading die?

I just finished making some long 5-40 bolts ( 1.6" ) out of 1/8" stainless welding rod. I made two passes on the rod. For the first pass I expanded the die to make an oversize thread then followed with the die set back to normal but still had to run slow and clear chips every 3-4 turns.

I even backed off the die completely to clear chips in the die. Stainless is a bear to thread.

John B

[Harold_V]

I just posted the following on the Live Steam Market Board. Although I did get welcome comments there, I thought it was the wrong place to put it.

Yes, it was, and it has been moved, just as this one will be moved.
Your task is not specific to locomotives, so your post is best placed in the General Machining Forum, where it will receive the best exposure.

Harold

[Harold_V]

Stainless is a bitch to thread.

It can be, John, but if you prefer to use stainless, I'd advise you to explore 303 S or 303 Se. Both of them are free machining and yield much better results. If the thread in question requires heat treat, you can select 416, which is also a free machining grade of stainless.

Cutting threads with a die is never a good proposition. A die head will generally solve the typical problems, however, as the cutting geometry is very different from a die. Problem there is the cost, which is hard to justify for a home shop.

Harold

[Benjamin Maggi]

Stainless sure is a tough metal!

[DianneB]

Just for the heck of it (<-- I did't swear!), have you tried measuring the rod diameter? Have you double checked that the die is the size you think it is? (Thread it on a commercially-made bolt to be sure.)

My old Southbend wont jog but I use the belt tension lever to advance the chuck when I am threading. I always bevel the end of the work in the lathe and hold the work in the chuck, put the die in a die handle, and press the die against the work (tapered end first) with the tail stock spindle to get the die started straight. Once you are on a few turns, it should keep going straight. I recently did some 1/4" SS this way with no problem.

Usually when something wont work for me I find out I have made an assumption that isn't true (like the size of the stock or the size of the die) and that's a good time to check everything and assume nothing!

[FLSTEAM]

Benjamin Maggi

Sorry about my choice of words. It has been fixed.

JB

[Al_Messer]

I bought some 1/4" CR rods from Tractor Supply that were very difficult to thread, so I went back to square one and measured them. Behold!! They were several thous over-sized! Guess I learned my lesson about always needing to measure stock before trying to thread it!

Al

[Fred_V]

I see 2 problems with what you are trying to do.
1. SS is usually over size so you have a problem from the start.

2. Trying to pull the tail stock along the bed doesn't work, at least for me it doesn't. I loosen the tailstock chuck from the taper and turn it by hand to feed it onto the work piece. I advance the tailstock spindle to keep the taper/die well centered. In some cases I can use the back gears and power feed the die but not with SS.

Your problem is that if the die gets just a tiny bit cocked when it starts it will pull the whole tailstock off to one side or done into the bed and make it all jam up. It's like trying to pull a ladder across the yard by grabbing the top of it if you see my point.

[kenrinc]

Might want to turn an inch or so down a couple thou and try again. I always turn the major diameter about .005" under then chamfer the end with a file before I run the die on.

I realize you haven't quite been able to get a thread cut yet but it brings up a related point which may be part of the problem: do not assume that the thread printed on the die is correct! I recently bought a 10-56 die that didn't cut a 56 tpi thread. I actually don't know what it cut! Threads didn't match any one of my thread gauges ...

After Harold turned me on to 416 SS I'm a happy man ...

ken-

[DianneB]

I recently bought a 10-56 die that didn't cut a 56 tpi thread. I actually don't know what it cut! Threads didn't match any one of my thread gauges ...

As I said, assume nothing, check everything!

[sautewes]

Thanks for all the input. But everywhere I seem to be getting hit with a "If it's Tuesday, this must be Copenhagen" syndrome. I have all kinds of measuring sticks and I use them. I mentioned that I had run about 3/4" of thread before I quit so except for the matter of not freely feeding the stock (NOT ss) into the die, the only thing missing was horsepower.

Wes