Newbie mistake.

[kirso]

I have just got a used Draper 90 lathe as my first lathe. It came with some tools but no chuck.
I bought a second hand but unused Multistar Duplex chuck and a Variform mk2 system screw chuck.
I was told the seller was unsure of thread size but believed it measured 3/4 ins.
Anyway the point is its the wrong thread. Upon closer inspection there are marks that say TH 38.
It does screw onto my 3/4 x 16 shaft. But it isn't correct. you can feel its sloppy and wrong.
What lathes take a TH38 thread or is there such a thread ?
mod edit
Thanks

 

[NazNomad]

T38 is a M33 x 3.5mm thread. Never heard of a TH38 though.

http://www.toolpost.co.uk/pages/Chucks_ ... _data.html

For ¾'' x 16 thread you need a T01 chuck. - For example... http://www.axminster.co.uk/axminster-cl ... tpi-504545

 

[kirso]

I found that link earlier. But I was unsure if it was correct as it was not showing TH38.
I double checked the chuck and it is etched into the back plate and on the box.
I also wondered if you could get adaptors to go between the 2 threads. It would maybe mean the chuck being further from the headstock. But as long as things are centered I don't see too much excess strain on the shaft or bearings. But don't know if there is such a thing anyway.

 

[NazNomad]

http://www.toolpost.co.uk/pages/Chucks_ ... rseSleeves

TP34M33 Spindle Thread Adaptor; 3/4 in.x 16tpi(F) to M33x3.5mm DIN800 (M)

 

[minilathe22]

Hello kirso, welcome!

You said that the chuck does thread onto the lathe, but feels incorrect? If this is the case then I dont believe that the thread can be an M33 as that is approx 1.3 inches in diameter, it would not fit at all onto your lathe with 3/4" diameter thread... so the adapter suggested may not work (unless I have misread your description).

Might be worth trying to establish the exact thread you have before purchasing any adapters. Is it approx 3/4" thread diameter?

 

[kirso]

when I measure the threaded section with Vernier, it shows as 18.4 mm diameter. That's from top of thread to top of thread. But this is the female side If you see what I mean. So does not look like 33 mm.
will have a troll through interweb and see if I can find anything.
It felt very loose when first going onto headstock. But did go solid at the end. But it does not feel right to me.
But it is definitely etched with TH38 on chuck rear and on box. Although it is written in pen on box.
Thanks for the welcome also.

 

[NazNomad]

Got a photo of that chuck? it might help identify it.

Is there a maker's mark under the jaws maybe?

 

[minilathe22]

My personal experience has been that the chuck can feel quite loose on the thread until it has bottomed out against the end. Does it appear to run true once attached?

 

[kirso]

attached is the pics of the chuck and screw.
Hope this helps.

 

[kirso]

My personal experience has been that the chuck can feel quite loose on the thread until it has bottomed out against the end. Does it appear to run true once attached?

I did not run it to be honest as was unsure if it was ok. It felt solid enough.
All my looking seems to point at it being a 3/4 x 16 but it is weird with the TH38 scribed onto it.
I will take it to a local engineering shop and see if one of the lads can identify it for me and hopefully confirm it is 3/4 x16tpi.
Being new to the game makes me a bit wary of things spinning around at 2000 rpm. I remember a CNC machine smashing itself up when I was doing some retraining many years ago. Flying metal is not a good thing in a workshop/ shed LOL
On a different note. How does one "thank" people as per the info under someones name ?

 

[NazNomad]

Over on the right, where the !report and quote buttons are, there's a little yellow 'thumbs-up' symbol.

 

[marcros]

looking at http://www.woodworkersinstitute.com/woo ... ar-duplex/, the chuck only comes in limited sizes- it will either fit or it clearly won't- the nearest next size is quarter of an inch bigger so will be so sloppy you would know. Screw it on well, and see if you have any play. you wont need to force it, it should spin on easily.

 

[Robbo3]

Draper WTL90 is 3/4" x 16 TPI as confirmed by the plate in this picture

I suspect that (as already mentioned earlier) the chuck is loose until it butts up against the headstock spindle. It is a poor design feature on Draper lathes (having owned two) where a portion of the shaft is a smaller diameter between the threads & the main spindle which allows lots of movement.

 

[Dalboy]

Let me check in the morning as that is the size that I had on a chuck and believe it was a 7/8" thread size. I managed to buy a new back plate for mine at 3/4" X 16. I know a German company brought the multi chuck brand.

 

[minilathe22]

Obviously do not run the lathe until you are convinced it is safe. If you know a local engineering shop they should be able to confirm whether it will stay on there or not. Hopefully you have everything you need to get it going!

Have you got any suitable bits of wood yet?

 

[Dalboy]

Been out to the shed and can't find my box with the details on it but as i stated I suspect that is what I said and is 7/8" thread

 

[kirso]

using some bits I had for learning purposes.
But will eventually be looking for some decent wood. But feel it would be a waste of good wood at the moment.
The little bit I have done up to now has been a relaxing experience. I found myself so focussed on the turning that other thoughts and worries just faded away.
But at the moment I am in the "playing" stage. Hope people understand that "playing" for me is when the outcome is not critical. If it goes wrong , no worries. I had a problem once in a plc programming group who went crazy cos I said to someone learning " have a play".

 

[kirso]

Been out to the shed and can't find my box with the details on it but as i stated I suspect that is what I said and is 7/8" thread

Hopefully I can get it checked tomorrow and post the result.
Thanks for the help.

 

[Blockplane]

If it does turn out to be a 7/8" X 16tpi- which is the thread for earlier Coronets, I would be very happy to swap my 3/4" chuck body for yours.

 

[Robbo3]

kirso, play,play & play to your hearts content, that's how you learn. I often practice on a piece of wood taken from the log pile.