Tips for Hand Threading on Lathe

[MikeW]

Need some tips on hand threading on lathe with die (in chuck), mainly to keep work from spinning, these will be drill press handles. This is a practice piece to test the measurements I figured out for the ball knob end (3/8" diameter, 16 NC.)

[300sniper]

that chuck key in the chuck with no hand on it scares me.

[MikeW]

that chuck key in the chuck with no hand on it scares me.

Two safegaurds on this one, Power off, and it cannot be started up without the gaurd over the chuck. You can see the trip above the chuck.

[PTSchram]

Two safegaurds on this one, Power off, and it cannot be started up without the gaurd over the chuck. You can see the trip above the chuck.

Relying upon interlocks is no excuse for poor practice and will someday get you hurt, if not killed.

Take another picture and replace that one, or face the wrath of the Pirate safety Nazis.

The first thing I saw in this post was the chuck key...

BTW-lathes by definition are used where the workpiece turns and tooling remains stationary.

[krb]

The first thing I saw in this post was the chuck key...

.

Thats the first thing I noticed too.

Regardless of safety features,It's a very bad habit.

As far as the workpiece spinning,tighten the chuck as much as you can(if you dont mind jaw marks),use soft jaws or convert to a 5C collet closer.

[1TON73K5]

Regardless of safety features,It's a very bad habit.




1000% true, thats just plain STUPID. I have worked at shops where you would get FIRED for that kinda of carelessness. I have also seen chuck keys get thrown across a shop before (NOT MY DOING) it WILL kill you. I do understand you have a safety switch and the power is off, but it's the habit that will hurt you or someone else. The one time you forget to kill power and for some reason you bypass the gaurd or something goes wrong with it and it does'nt work and you do that, you will be in a world of hurt man. GOOD machine shop practice is to remove the key ALLWAYS! Every person I have ever trained to run a lathe, thats one of the first things I teach them.

Why don't you just single point the threads? Is it an odd size, or metric thread your lathe won't cut? IF you have a mill, mill three flats on the shank of the die holder to keep it from spinning in the chuck. As far as the material, just crank the chuck tight.

[PTSchram]

GOOD machine shop practice is to remove the key ALLWAYS!

Good machine shop practice is also to use the machinery as it was intended, ie, turn the part, tool remaining stationary.

I don't think I've ever seen a thread backfire as quickly.

[jamscal]

It's common to have a tool in the spindle, and the work mounted on the carriage. I could probably find pics of 1000 applications. It's been done forever, and safely. One of the reasons a lathe is so versatile.

It appears his work is in fact in the spindle, and tool is in the tailstock.

I have a handcrank for my lathe. Fits in the headstock through hole. Makes it easy to cut threads. Cut, back off to break the chip, crank again. Also good to single point up to a shoulder, and your wife can crank when the power goes out, for general lathe work:D

You can wrap your part in emery cloth and then chuck it up. This sometimes helps.

You can tighten down on the chuck more. Be careful.

You can single point -a little bit-, and then the die will work better and easier.

-James

[300sniper]

BTW-lathes by definition are used where the workpiece turns and tooling remains stationary.

i think that is exactly what he is doing.

like asked before, why not just single point thread them?

[stainless steal dave]

Relying upon interlocks is no excuse for poor practice and will someday get you hurt, if not killed.

Take another picture and replace that one, or face the wrath of the Pirate safety Nazis.

The first thing I saw in this post was the chuck key...

BTW-lathes by definition are used where the workpiece turns and tooling remains stationary.

do you remember some of the issues you and i were discussing in the bridgeport thread by mayka a couple of days ago? the last post i made in that thread pretty much sums up what is now being discussed in this thread p.t. this is not a personal attack aimed at you-although i have never met you personally-i like you. the last 2 sentences in my last post pretty much cover it.

[fj40guy]

Back the subject of threading...

First couple of times, just spin the lathe BY HAND. Works to have
a buddy actually do the hand spinning (unplug the machine! to prevent
hitting the on handle...).

As the work piece is spinning, you lightly feed the die into revolving work
piece. Well, once the die feeds in... you let off the die (it will spin in place) until you turn off the machine. Then "unscrew" the die by hand.

With the tail stock, Morse taper drill chuck, and die holder.... everything looks solid. Most likely when thread starts it will pull out the Morse taper... The die holder needs to "float" on a shaft. Shaft just keeps it aligned.

I'll post up my home made die holder this weekend. Then again I don't want the OSHA patrol jumping me (Two bars come out perpendicular to the die holder.... used incorrectly it will break a wrist... I size the material to size, MACHINE OFF, use the hand threader to cut the thread, remove the tool, MACHINE on to finish up machine/parting operation. )

After a few hundred of those plugs I really want a screw machine. :)

[PTSchram]

i think that is exactly what he is doing.

like asked before, why not just single point thread them?

OK, perhaps stating that he was using the tailstock chuck versus the headstock chuck would have made it more clear to me.

Either way, the backfire was entertaining. A self-ejecting chuck key might be a good idea.

My experience has been that threading using a die in a lathe is not the best way to do it. Chasing a 3/8-16 thread should be pretty simple and nearly as fast and would result in a much nicer thread (in most cases).

PT

[YJTypeR]

Smashed my middle and ring finger in a lathe with the chuck key a few months ago....got in a hurry and thought the machine was off. I got real lucky and just broke my finger tips and did a nasty number on my finger nails. Luckily it was a cheap chinese chuck wrench other wise I would probly have lost both finger tips. I keep the broken wrench above my work bench to remind me when I think about cutting corners again.

[fj40guy]

My experience has been that threading using a die in a lathe is not the best way to do it. Chasing a 3/8-16 thread should be pretty simple and nearly as fast and would result in a much nicer thread (in most cases).
PT

PT -- I'm threading 14mm threads into aluminum. For chasing a thread I need a steady rest and multiple passes. Die threading is much faster timewise.

Self ejecting chuck key is a good idea, still one of those "when I get around to it". Irony is when the kid in the shop I find myself being very conservative around machines, checking for safety.... by myself I go back into that 'get it done' mode. No, NEVER any rags for polishing. Still need to buy/make some nice file handles (I stand to the side, but that tang could be leathal)

Tom

[PTSchram]

PT -- I'm threading 14mm threads into aluminum. For chasing a thread I need a steady rest and multiple passes. Die threading is much faster timewise.

Self ejecting chuck key is a good idea, still one of those "when I get around to it". Irony is when the kid in the shop I find myself being very conservative around machines, checking for safety.... by myself I go back into that 'get it done' mode. No, NEVER any rags for polishing. Still need to buy/make some nice file handles (I stand to the side, but that tang could be leathal)

Tom

In that case, you're right. I work with steel far more often than any other material.

I was a fairly safe person, then I found myself working in bug business where it was pounded into me. Then, I found myself in the position of Environmental, Health & Safety Manager in an auto parts factory. One becomes VERY safety conscious in that situation and for some reason, it begins to intrude on your everyday life. That said, I haven't been badly injured in a LONG time.

[fj40guy]

One of the photo's I had on the wall was of an X-ray.... with four shortened fingers (clean cut):

Caption was "I was just going to make one last cut of the day" He slipped and his hand went right across the table saw. Ouch.

Just a little mental reminder to think first.

[gregers05]

that chuck key in the chuck with no hand on it scares me.

x2 i did that shit once and turned the machine on and scared the everliving crap out of me. luckly nobody was standing in front of it and it threw it to the ground. needless to say it hasnt happend again.


as far as threading it, just keep it in the highest gear and turn the head with the chuck in it. but make sure you back off on it to clear the chips instead of one continuous cut. make sure you have the machine unplugged.

power tapping-
other way you could do it is turn the machine its lowest speed and disengage the brake on the tailstop. turn the machine on and let it pull the tailstop with it. ive never done this with a die before but ive done it alot with taps

[PTSchram]

One of the photo's I had on the wall was of an X-ray.... with four shortened fingers (clean cut):

Caption was "I was just going to make one last cut of the day" He slipped and his hand went right across the table saw. Ouch.

Just a little mental reminder to think first.

October 11, 1982, I cut the fourth and fifth digits from my left hand. Fortunately, I was living in close proximity to the best hand surgeon school in the world. I have complete use of both fingers now.

[jasonmt]

that chuck key in the chuck with no hand on it scares me.

I try to stay away from mills/lathes etc. as the "old bastard" in the family who has been doing it for 50 years can do it either 10x faster or 10x better than I can and he works cheap but even he only runs these style of chuck keys in the shop:

http://www.victornet.com/productimages/368.jpg

If I had the thread what was shown in the first picture it would be chucked in a Ridgid 535 though.

[braxton357]

By now you could have taken the workpieces, put them in a vise, and threaded them by hand the old-fashioned way. :flipoff2: Otherwise I agree, what's wrong with single point threading?

[fj40guy]

Tw items.... 'arms' to hold the die are 12.5" in width. 13" swing on the lathe.

The die holder has a loose (0.002") fit on the plug that remains stationary (guide to assist in starting the thread straight).

Only time I like single point threading... 12L14 stock. :flipoff2: