Tailstock dieholder

[David Thompson]

I am not exactly a beginner, but some of my problems seem rather elementary. For instance, I can cut a thread by hand using a diestock, but of course there are the usual problems with keeping it square. A tailstock dieholder seems the obvious answer and I bought one from Chronos to suit four sizes of button dies, although mostly I am just using BA and ME sizes.
The problem is, I can never get the thread to start. It usually just graunches the end of the prepared bar and never gets enough of a grip to pull the die along the barrel of the dieholder.
I ask myself, is there enough chamfer on the end before I start? Is the die the right way round? Should I be using the lathe to power the operation? (I never dared so far).
Any wrinkles on this operation would be very welcome.

Cheers, David.

[dickdastardly40]

I've never used a tailstock dieholder though they do seem a good idea, is it spring loaded to keep pressure on the die or are you allowing the tailstock to advance with the die?

If you tap or die by hand you need a certain amount of pressure to get the thread started, try doing that first then use the holder to keep it square once it's established. Ensure the die is tapered start into the job first (usually the side with the size etched or stamped on).

I use a diestockand keep it square backing it up with an empty tailstock just advancing it enough at a time to stop the thread going drunken.

Let us kow how you get on.

Al

[David Thompson]

Thanks Al,

The type I have has a parallel barell which plugs into the tailstock taper. When the die has caught, it should just draw the die-holder freely along the graesed barrel as the thread advances.

David

[GeorgeRay]

David
I assume that you ensure that the middle screw in the die holder is properly engaged because otherwise you might be trying to cut a thread that is too small. I always slacken off the outer screws and tighten the middle screw quite hard for the first cut. Then go back and loosen middle slightly and then tighten outers. This is what I was taught many more years ago than I care to remember. This method works for me even if I dont actually put a small taper on the end of the bar. Hopefully this isn't teaching Grandma to suck eggs.

[lancelot]

You bought your die holder from Chronos...so did I...I had exactly the same problems you had...threading diam. correct for die. light chamfer... light pressure feed on tailstock... still grunged the thread. So I did a bit of investigating and found that the recess that the Die fitted into was not letting the Die open up enough to allow the threading process to start... if I forced the Die on to the material I ended up with a loose sloppy fitting...So what I did was to open out the Diameter of the Die holder Barrel that the Die goes in to by about 3 thou'' ...this allowed for the Die to be opened up slightly when in the Die holder by using the adjusting screws ...the central one when screwed in pushes the die open a little allowing easier control of threading...I use plenty of lube oil on steel...
Hope this has helped,
All the best for now,
John.

[steam4ian]

G'day all.

Glad I'm not alone with dies, I have trouble and I thought it was the cheap dies. I made my die holder so I can't blame Chronos! I've had better results cutting the threads with the lathe but that's tedious when you have to set up the lathe each time.
I hope this thread (pun intended) stays open because there must be even more expertise out there.

Regards,
Ian

[Lurkio]

David,

Seems you are doing things right with your hand-held die holder as you are able to cut threads OK that way.
Lancelot may have the answer. Compare the i.d. of your hand tool with that of the tailstock die holder to see if the latter is too small.
A nice taper rather than a chamfer on the end of the job will help the die to start.
Other than that follow the other good advice posted by Al and George above.

Lurkio.

[spurley]

Hi All

I think Lancelot (John) is right about the size of the 'die retaining hole' being too small to allow the die to expand for adjustment. I too made my own holder but copied the dimensions for the die holes from my die stocks. It is a very simple device but I find that it has revolutionised my thread cutting in the lathe. I am talking small stuff here BA and ME up to 1/2". , I will tackle some screw cutting one day, probably ACME square thread all I'll need is an application!

Cheers

Brian

[houstonceng]

Interestingly, the late, great George Thomas - may he rest in peace - stated that he adjusted the split dies in his homemade holders (one for each die, part of the TSDH set he illustrated in his book) so that they cut the required size in one pass.

I've had no problems with my commercial TSDH set (IIRC bought from Chronos), so long as I push the holder firmly onto the work using the tail-stock feed until the thread is established. After that, I let it slide along the mandrel by the threading action.

I have noticed, however, that a couple of cheap dies have the "dimples" and taper into the split a little out of position such that the defects cause these dies to "tilt" in the holder. IIRC George had the same problem. These dies won't cut a straight thread using the TSDH, so I save them for "blacksmithing jobs" in a die-stock.

Happy threading

BTW. It's also worth checking that the (usually) two holders for the lager dies fit correctly into the appropriate end of the TSDH. Carelessly inserted - or bacfly manufactured - they can give a "tilted die effect".

[mackintosh]

Just one thing I would like to add is you get what you pay for with dies. HSS are the best and I use them for all my commonly used dies and also the small 10BA and 12BA taps are less likely to break.
Bob

[Roger Mason]

Hi,

I'll just add my two penny-worth!

Like others before me I had to open the bore of my tailstock die holder a few thous. This certainly improved things.

I find it is important to ensure the die is pressed back into the holder, to ensure it is held square. The tapered screw which opens the die has a tendency to force that side of the die out of the holder and I find the die needs tapping back in to ensure it is square.

I have also found by trial and error that a die with a tapered lead in (the side with the writing on it) starts better on a rod with a perfectly square end. If I chamfer the end of the rod, with a chamfer on the die as well, the first cut is trying to start on a long front. With a square end the die starts cutting over a very short length - much easier to get it cutting properly.

I hope this helps.

Cheers,

Roger Mason, in sunny St. Agnes.

[chris vine]

Just to confuse matters,

I once had a tailstock die holder which cut badly formed threads, too much cut away. I found that the hole for the die was too large. This caused the die to be too much off centre and, being restrained by the tailstock, made it cut grossly undersize.

Be careful about opening the hole out too much.....

Chris.

[ron]

I bought one from RDG Online and have never had any problems with it, they're a marvelous invention, if in doubt I tend to do the same as George Ray and do the first cut with an open die, but I've found with practice I know where to set it with the more common sizes I use.

Ron

[Jo]

I too have a couple of these tailstock holders and have experienced no real problems, except that with double enders it is important to remember to make sure the allen screws are below the surface height if you holding the body by hand to do the threading under power.

I find that a parallel mounting is useful as it allows it to be used in the drill chuck in either the lathe or drilling machine.

Jo

[districtgrandmaste]

I've been using the same Tailstocxk dieholders for more than 30 years. I reckon that a chamfer on the end of the stock being threaded is essiential. Anything over 5/16" I do some screw cutting and just finish with the die, but most of all I made one of George Thomas's Mandrel handles quite recently and it is a Godsend. Previously I was often tempted to put on the power and the results were variable - probably because old dies don't take kindly to the force exercised under power. Now pop the handle into the headstock - 2 1/2 turns of the locking bar, bring up the die and tap the length in a trice!

[David Thompson]

Thank you, gentlemen, for all this advice. It is a relief to know I am not the only one with this problem.

I have measured the ID of my tailstock gadget and my hand held diestock and it is indeed a little tighter. I have often thought there seemed very little range of adjustment. Another problem I did not describe is the tendency to turn the material in the collet, however hard I tighten it up, which again suggests it is a bit tight. Thanks for the suggestion to open the bore a trifle.

I do agree about the ground HSS dies being superior and I will have to grit my wallet and do something about that.
I have also tried starting the thread with a little screw-cutting, finishing off with the die and I think that is quite effective, but also a bit of a chore.

When cutting threads by hand, I always go backwards and forwards a little at a time and I do find it is bit harder to achieve that with the tailstock holder. I have no mandrel handle and if I use the collet drawbar handle, there is a danger of unlocking the collet on the reverse stroke.

[dickdastardly40]

Dave,

What sort of lathe do you have? I can rotate the myford backward and forwards by using the belt (watch out for trapped fingers in the pulleys). Depending on which pulley you are on you get quite good advantage.

If no good then would one of those 'Boa' style strap wrenches work to turn backwards if you use the collet closer to turn forwards?

I understand a 3 phase inverter alows you to inch the spindle, does anybody with one of these know if it can be used for tapping?

I find gripping both sides of the belt to hold the spindle stopped when changing chucks or doing up the collet drawbar works well also.

Al

[chris vine]

Hi Al,

I use a myford with an inverter drive and use it for all tapping and threading with a die (dieing???)

I wouldn't go back to single phase for all the tea in China. The worst of single phase motors is having to wait for so long before you can reverse them, while they spin down.

Chris.

[David Thompson]

Al,

I have a Boxford 4.5" lathe with the belt fully enclosed but it does have an inverter drive so I can make it inch round very slowly, although it had never occurred to me that the torque would be high enough for tapping at such low speeds. Again, I think reversing the direction should be possible, but I may need to add a switch. I can certainly do it by programming the inverter. Ah, I need to go and look at it to see if there is already a button for direction control.

David

[chris vine]

Hi David,

There may not be a button but there will almost certainly be a terminal or two which need connecting to give reverse.

A good source of information is the Radio Spares RS website. If they stock you type of inverter (or similar) you may be able to down load the manufacturer's data sheet as a pdf.

Chris.