lathe

[paulmowers]

Hi Guys

Just wondered if anyone knows what make this little lathe is?
Thanks Paul..

 

[Pete.]

Dunno but it's carrying a HUUUGE chuck. Looks a useful little machine though.

 

[paulmowers]

Yes it is a massive chuck for the size of machine, I don't like that style either, its too easy to hit the jaws with the tool or toolpost when working on small short peices. Idealy I want to get a good normal chuck that will fit it which is why i would like to find out what it is.
I have done some reasonable work with it but I need to renew the spindle bearings as all adjustment is used up, and make up another set of speed change pulleys, I have 3 speeds at present , fairly ok, too fast and way too fast!!!!

 

[scott0031]

Yes it is a massive chuck for the size of machine, I don't like that style either, its too easy to hit the jaws with the tool or toolpost when working on small short peices. Idealy I want to get a good normal chuck that will fit it which is why i would like to find out what it is.
I have done some reasonable work with it but I need to renew the spindle bearings as all adjustment is used up, and make up another set of speed change pulleys, I have 3 speeds at present , fairly ok, too fast and way too fast!!!!

You dont need a new chuck, you need new jaws. Those ones are for holding larger diam jobs. You normally get 2 sets with a 3 jaw self centering, the ones you want and the ones you have!

I will add a smaller chuck would be a good idea there is to much overhang and mass spinning about for those bearings................ that weight on such small phos bronze bearing will generate extra unwanted heat. That might be half the trouble your having.


Kind regards,


Scott (ward eng)

 

[scott0031]

Ahhhhhhhhhhhhh i forgot to add, if its a new chuck your after don't worry about the make of the machine. All you do is.................. take the chuck off, it will/should be mounted threaded spindle nose. Take note of the TPI of that thread and its diam and find out what the thread is (its bound to be english)

The chuck will be mounted on a back plate, back plates can be bought. BUT! if your getting a new smaller chuck its likely you can use the old back plate as its pretty large. You can turn that down to suit the regester on a new chuck! Yours may not have a regester hard to tell from the pics.......... hopefully problem solved! As long as its fairy concentric with or without a register all should be good.


Kind regards,


Scott

 

[paulmowers]

Thanks Scott

The chuck is held on by 3 5/16 whitworth hex bolts that pass through a flange? on the end of the spindle. Cant see any evidence of this flange being removeable from the spindle but I may well be wrong. When ive taken it apart before I have had to release grub screws from the pulleys and pull the spindle out towards the tail stock.
It is this 3 bolt fixing of the chuck that seems to be a hang up on replacement.
Any ideas?

 

[scott0031]

Thanks Scott

The chuck is held on by 3 5/16 whitworth hex bolts that pass through a flange? on the end of the spindle. Cant see any evidence of this flange being removeable from the spindle but I may well be wrong. When ive taken it apart before I have had to release grub screws from the pulleys and pull the spindle out towards the tail stock.
It is this 3 bolt fixing of the chuck that seems to be a hang up on replacement.
Any ideas?

Investigate it further, that 'flange' is the back plate. Im 100% certain that will be threaded onto the spindle nose................ thats how you change between various chuck types ie 3 jaw, 4 jaw, and face plate/catch plate. If it doesnt have a threaded spindle nose.................. well it will be a first.


It should undo in an ummmmmmmmmmm anti-clockwise direction. Ok do this (not the best practice in the world, sometimes needs must) put the chuck key in make sure the machine is out of a back gear if it has one. This is the important bit hit the chuck key at its lowest point where it enters the chuck. A mallet is best copper if you have it. When you hit it, dont hit it hard with huge force what you need is a very sharp blow, its like a shock rather than a big impact. You can try the same method with the palm of your hand first off. What ever you do, if it dont come off easily dont sit there smacking it to death. You will damage things!

If this fails you can try another tactic to break the seal. What you do is this.......... again with the mallet hide end preferable this time. Copper end would be better but use something betweenn the mallet and the chuck bit of ally or steel plate so you dont bruise the chuck. You then again with a short very sharp blow hit the face of the chuck. This uses the method of recoil to break the seal, then again try the chuck key method to undo.

I will say again a short sharp blow is ''vital to success without damaging things on the machine. If your not confident practice it first.

Oh take the jaws out first in case you miss and skin your knuckles lol I dont wanna be sued!

good luck..............

 

[Pete.]

Looks like there's a clear join between the backplate and the spindle. It'll un-screw, but it might be hard to shift.

 

[paulmowers]

Thanks again, when i get a break from paying work I'll have another look and try getting the backplate off.

Thanks paul

 

[chap]

Another way you might try to get the back plate off, is to remove the chuck then drill one end of a bar to bolt to two holes on the back plate. You can then either strike this bar as scott has described above, or try locking the spindle in some manner without damaging it or any components, and using a tube slid over the bar as a lever.

Once, to get the chuck off a pistol drill, i used a 1/2" allen key with short end done up as securely as possible in the chuck, then had to take the casing of the drill apart and use a pair of mole-grips very tightly on the shaft to get enough perchace to undo it!

 

[scott0031]

Another way you might try to get the back plate off, is to remove the chuck then drill one end of a bar to bolt to two holes on the back plate. You can then either strike this bar as scott has described above, or try locking the spindle in some manner without damaging it or any components, and using a tube slid over the bar as a lever.

Actually thinking about. Ive been a bit thick there, long time since i had a lathe with screw spindle nose. This is a method i used on one machine as it was always a bum hole of a thing to get the chuck off. That other way is to lay a nice size section piece of bar something like 3/4 x 1/2 on the face of the rotate it until it locks against the jaws of the chuck. Then use the sharp blow technique.

Similar thing to the method chap has mentioned without taking off the chuck. Chucks are pretty tough things and can a take a bit of force. They can be trued up easily so dont worry to much if it runs out a bit after a bit of brute force.

 

[paulmowers]

its off

Hi All

Thanks Scott and everyone else who suggested the backplate unscrews, you were abolutely right. And I managed to crack it off tonight, marvelous how easy something is when you know how it comes apart

So now the next problem, I have measured the o/d of the threads and come up with 1 1/8" , the threads extend for under an inch so I have counted the threads for 1/2" length which amounts to 6, so presumeably the thread is 1 1/8" x 12 ????? Does that sound right

Any suggestions as to how to go about getting the right size backplate and or chuck to fit please.

Pictures below, a bit out of focus but hope you can see well enough.

Thanks Paul..

 

[scott0031]

Well done! Everything is easy when you know how


ok right first off, whats the diameter of the existing chuck? Second providing you have measured the thread correctly it comes up as 1 1/8 UNF - 12 tpi (tpi being teeth per inch)

As i mentioned before you might not need to get a new back plate you allready have one. A smaller chuck will have a smaller regester, so it will be a case of turning down the OD of your back plate to fit the new chuck. Next step will be spotting the holes from the chuck to the back plate drill them and your done.


Finding a new chuck just search the net, bound to be loads on ebay and many model engineering type places will do them. what you need to look for is a 3 jaw self centering chuck of the diam you require.

 

[Pete.]

Remember if you are measuring threads over half an inch that the first one is number 0, not number 1. I made that mistake when I got my first lathe, made a backplate at 10tpi instead of 8.

 

[scott0031]

Here is a back plate for starters and dirt cheap! 1 1/8 x 12 tpi.

http://cgi.ebay.co.uk/100MM-LATHE-C...s_SM?hash=item439a15e4d3&_trksid=p3286.c0.m14

 

[HasBean]

1 1/8" x 12 Whitworth is a standard thread for Myford lathes, check Chronos, ARC Eurotrade, RDG Tools etc, usual suspects....

 

[paulmowers]

Hi guys
Strewth aren't chucks expensive! had a bit of a look around the net and ebay, prices seem to be £75 and up, although axminster have one for about £46 or so, but am wondering if its cheap tat?
Also re the backplate, thanks for the ebay suggestion scott, but I am a bit concerned that I have the tpi wrong as pete said when counting tpi's over 1/2" start at 0 rather than 1, that would make mine 5 over the 1/2" so 10tpi? So I think I will find a chuck first and then see if my plate can be machined down without the original holes being a problem.

update.....been surfing again, found one, 3 jaw self centering with int and ext jaws, new, not chinese (i hope) 100mm (more like it) £40 incl delivery.


Paul

 

[shenion]

Well you count full threads. put the start at the peak of one thread. Then count from there, the 6'th thread should be in line with your 1/2" mark.

1 1/8 - 12 seems about right. 10 TPI is usually 1 1/2" spindles.

£40 is cheap.

Chinese chucks are ok. Have had 2 that worked fine. The issue is accuracy. Then again, a 3-jaw self-centering chuck is more for speed of setup. 4-jaw independent are for accuracy but take a long time to set up.

My last Chinese one had about 0.002" of runout. You need to spend a major chunk of change to get better.

For accuracy, I made an ER40 collete chuck. ER32 would probably be better on a smaller lathe.

Has anyone determined the make? Whould make it easier to identify the spindle and tailstock tapers.

The chuck may be usable, the jaws may be reversable.

 

[paulmowers]

Thanks for the advice Scott, by the sounds of it, how I measured the threads from the start of the first to the 6th right on the 1/2" mark should be right for 12tpi, so I now know what i need if it comes to a backplate change.
So just have to wait for my new chuck to arrive, and the new oilite bushes for the spindle, actually on the subject of oilites, you may have noticed on the pic that my lathe has had grease nipples fitted to lube these bushes, is it best to replace these with oilers?
I am still stuck regarding a make, although i have been labouriously wading through all the lathes specs and pics on lathes.co.uk and so far not found a match, found a few similar but none with a bed like mine.
going back there now to continue the search...........

Paul..

 

[shenion]

I would use oil cups and add oil about every time you use it. Grease will collect dirt and cause wear as there are no seals on most small lathes. Use a good machine oil, not motor oil.