Can I change insert on Record Power SC3 chuck?

[BigWing]

I have a Jet JWL-1221VS lathe which has a M33 x 3.5 thread on the spindle.

I bought from eBay a Record Power SC3 Geared Scroll Chuck Package which said it had a "M33 x 3.5 thread". Now that I have it, I can see that the thread is in fact 3/4" x 16 TPI.

Rather than return it, can I just buy a different insert for the chuck (though I can't find any information anywhere about how to change the insert)?

 

[CHJ]

I don't know the Chuck but is the body thread that the insert is fitted into by any chance 33 mm.
It's most unlikely that a 100mm chuck would be capable of accepting a 33mm insert, they usually have to be directly threaded.

 

[BigWing]

I don't even know if the chuck I'm looking at does have an insert. How can I tell?

The manual is very frustrating as it does talk about inserts but it covers both the SC3 AND the SC4, and I'm wondering if only the SC4 allows changing the insert.

 

[themackay]

I stand corrected the SC3 does not have an insert I was looking at my SC4 last night

 

[bobajobob]

I have two SC3s threaded 3/4". They are directly threaded there is no insert. Only the larger SC4 is fitted with inserts. Adaptors ( M33f-3/4"m) are available. Axminster sell Jet made versions but they are not cheap. ( http://www.axminster.co.uk/spindle-thre ... rs-ax20851 )

 

[BigWing]

Thanks for the responses - it's a shame there is no insert.

 

[selectortone]

I upgraded to a larger lathe a few months ago, and while I have an M33 threaded chuck for it, I was left with four chucks threaded 3/4"x16tpi. I use an adaptor with them and it works fine. The one from Record Power is ten pounds cheaper than Axminster's. The variant you need is CWA121 Thread Adaptor - M33 x 3.5mm Female to 3/4" x 16tpi Male - available from most Record Power stockists.

You can never have too many chucks!

 

[BigWing]

Thanks for the info on the CWA121 - oddly, my searching hadn't uncovered that one. Is it really OK to use an adaptor, or would I lose out in terms of stability, or runout....? I'd lose a little in useable spindle length but I can live with that.

 

[Random Orbital Bob]

No you should be fine. I also upgraded from a 3/4" x 16 tpi threaded lathe and got stuck with incompatible chucks. I also bought the adaptors mentioned here and on one level they're helpful because they extend the chuck away from the headstock housing allowing easier access to the spindle side of pieces. I've noticed not one jot of degradation in either runout or any other vibration. Don't forget that with M33/MT2 0 everything is much more robust anyway which has a big impact on dampening vibration.

Just get them, they work fine and will upcycle those valuable chucks. I now have chucks dedicated to pin jaws and cole jaws from that old stock. Very handy indeed!

 

[Dalboy]

I have a Jet JWL-1221VS lathe which has a M33 x 3.5 thread on the spindle.

I bought from eBay a Record Power SC3 Geared Scroll Chuck Package which said it had a "M33 x 3.5 thread". Now that I have it, I can see that the thread is in fact 3/4" x 16 TPI.

Rather than return it, can I just buy a different insert for the chuck (though I can't find any information anywhere about how to change the insert)?

I would return it and ask for the correct one as advertised.

 

[BigWing]

Thanks for the advice - I will order an adaptor. I could send the chuck back but it's unused and came at a very good price, and it came with 3 different jaws - so worth persevering with I think.

 

[selectortone]

...Is it really OK to use an adaptor, or would I lose out in terms of stability, or runout....?

I was concerned about additional runout, but it hasn't been a problem. I had also heard concerns about the extra length with the adaptor, but again it doesn't bother me. The extended body on my new M33 Axminster SK100 with the allen screws for reverse locking means it is almost as long as my old (non-reverse locking) 3/4" SK100 plus the adapter.

For the purist it probably wouldn't be considered an ideal engineering solution, but, in practice, I'm just happy to be able to use my old chucks with the new lathe. Anything really big or badly out of balance I mount with the new chuck.