Is Sheraton spindle thread different to hercus?

[Com_VC]

I'm trying to fit a chuck that came from a hercus 9" to my sheraton 9". It screws on fine but it doesn't go all the way onto the register, there is a 5mm gap. I tried holding onto the belt and giving it a bit of force but it still won't go on any further. I would have thought it should screw on without any necessary forces? I thought they ran the same configuration.

The original chuck and the faceplate that came with my lathe screw on easily.

I have an old headstock here that came from a hercus and the chuck i'm trying to fit to the sheraton fits this fine.

So are they different? Is there anything I can do to make it fit my sheraton?

I cleaned all the threads with a toothbrush and chucked for burrs etc.

Thanks

[pipeclay]

When you say it wont screw all the way on,are you reffering to the register on the Backplate screwing up to the register on the spindle?

Or is the Back plate running out of thread.

Have you measured the length of thread from the bare shaft of the spindle to the end and compared it with the Hercus?

Have you measured the length/depth and diameter of the recess in the back of the Hercus backplate and compared it to the Sheraton.

Sometimes this under cut needs to be lengthend.

If that is the case remove the backplate and screw it onto your spindle in reverse and machine it deeper or larger in diameter,DO NOT TOUCH THE REGISTER FACE.

If the thread is intergrated into the chuck you may have to hold it in a 3 jaw or 4 jaw or face plate so as to be able to machine it.

[Com_VC]

Yeah register on the Backplate wont screw up to the register on the spindle.

I just measured both the sheraton and hercus thread length and they measure the same.

I just measured the register on the back plate of the chuck that was originally on the sheraton and compared it to the hercus chuck and it looks like the diameter of the hercus is around half a mil smaller.

So should I do as you suggested and remove backplate and screw it on in reverse and machine the register so it is larger in diameter?

Would I need a boring bar to do that or any other suggestions?

Thanks

[morrisman]

Try putting some blue marking dye on the Sheraton spindle and see where the Hercus chuck jams , it will make a mark .

I think the later Sheratons used the UN 8tpi thread which is 60 degrees . If the chuck is from an older Hercus it might be a BSF thread with a 55 degree thread in the chuck ?

Do you have any thread gauges ?

Mike

[Com_VC]

Oh no, that doesn't sound like good news. I don't have any marking blue or thread gauges.

It does seem to screw on ok, it's just I cant get that extra 5mm so it sits on the register.

[pipeclay]

99.9% sure it will be 1 1/2" x 8 UN thread.

If you have a boring bar use that to take the needed amount out of the back plate.

If you havent got a boring bar just grind up a piece of HSS so that it will go into the bore with out rubbing on the side.

Dont worry if there is no square shoulder in the recess after you machine it.

Dont worry if you happen to take some material off the diameter when you correct the depth,
Just make sure you DONT TOUCH THE REGISTER FACE.

For what you want to do dont worry about using any blue it will be a waste of time and money.

[tanii51]

as far as i know all 9 inch hercus were 1 1/2 x 8 un
i just went and had a look at one of my 9 inch hercus spindle thread..... distance from end of thread to shoulder is .875inch/22.23mm
inside the chuck it looks like if that distance is any longer it may not screw on the full distance

if the chuck is a one piece you maybe out of luck or maybe you can use the original backplate remachined to fit if its a plain back chuck
john
if you havent got any bearing blue try black texta it may show where its hitting
oops pipeclay beat me too it

[pipeclay]

Just so you dont worry too much the Shareaton register length or the bit at the end of the spindle is longer than the Hercus,if you can find someone with a Southbend ask them to measure there spindle,you should find that they are allmost the same if not the same.

When I do the Backplates I make them so they fit all of the clones.

[Com_VC]

So are you pretty much saying there is too much thread on the back plate and that's what's stopping it from going in further?

[pipeclay]

If the recess is not deep enough or large enough the plate wont hit home on the register.

[Com_VC]

So the register face you are talking about is the front part of the backplate.

So as long as I dont touch that and change the diameter of the register of the back plate I should be fine.

It won't matter if I go to deep, is that what you are saying?

Sorry I don't know all the correct terminology right now, I just don't want to bugger this up

[morrisman]

So the register face you are talking about is the front part of the backplate.

So as long as I dont touch that and change the diameter of the register of the back plate I should be fine.

It won't matter if I go to deep, is that what you are saying?

Sorry I don't know all the correct terminology right now, I just don't want to bugger this up

The backplate is easy to buy , or you can make one yourself . 1 1/2 - 8 back plates are available from quite a few suppliers

Don't touch or change anything on the spindle itself .. the register on it or the thread


http://www.tools4cheap.net/proddetail.php?prod=15back


Mike

[pipeclay]

The spindle will be threaded but not upto a shoulder.

The unthreaded section of the spindle maybe the same size as the threads or it could be a little larger.

The back plate you have know for the Hercus may not fit over the un threaded section on the Sheraton spindle,if this is the case the bore in the back of the Hercus back plate will need to be enlarged to fit over the Sheraton spindle.

There is a step on the end of the Sheraton spindle which will fit into the Sheraton chuck or face plate that you are now using,this step may be a longer than the recess cut in the Hercus back plate,if this is the case the step in the Hercus back plate needs to be made at least as deep as the Sheraton step.

If you hold the Hercus chuck up to your spindle with the jaws facing the tailstock the flat area at the rear of the chuck will be the register,this register needs to seat against the Sheraton spindle,THIS FACE YOU CAN NOT TOUCH.,the same way your other Sheraton chuck and face plate do.

[Com_VC]

When I screw the back plate on in reverse the thread is pretty much flush with the end of the spindle so it won't allow me to machine it without cutting into the spindle.

[Steamwhisperer]

When I screw the back plate on in reverse the thread is pretty much flush with the end of the spindle so it won't allow me to machine it without cutting into the spindle.

You could make a spacer ring to go on the spindle first before you screw the back plate on

Phil