Jacobs Chuck Drift.

[shedhead]

I have a problem with my 2mt Jacobs Chuck. When I have it mounted in my lathe it will work it's self loose and drift forward in the head stock. Even if I fit it tight it always runs forward and I have to stop to refix it. What is the problem? Does anyone else have this happen? and what can I do to stop this happening?

 

[Bodrighy]

If I want to use my Jacobs chuck in the head stock I hold it in the ordinary chuck.

Pete

 

[johnny.t.]

Dermot, mine does this too, to prevent it I give it a good hard tap in with a bit of wood :lol:

JT

 

[Richard Findley]

Hi Dermot,

A tap with a Dead-Blow mallet works a treat!! Not a Whack, just a tap. You should see the taper visibly move, probably only a fraction of a mm, but this will seat it properly and safely.

Another top tip is to position your tool rest in such a way that if it does come out it only hits the tool rest and you can safely just press stop and let it slow down in it's own time without trying to catch it and hurting yourself!!

HTH

Richard

 

[shedhead]

Thanks for the info. I will use my wooden mallet to tap it in a bit tighter.
Pete I guess the most obvious answer was the one I did not think about.

 

[Alf]

A chuck with a draw bar is the slightly less, er, "hit it harder" solution to the problem... :wink:

 

[jasonB]

As Alf says if you are putting any sideways load on the chuck then you need a threaded arbor and a drawbar, Tang arbors are only for drilling.

Jason

 

[cornucopia]

I've never got around to making a draw bar for my lathe so i use the tailstock with a scrap bit of wood to prevent it from coming out.

its also worth checking that the end of the morse taper isnt bottoming out before the taper is allowed to do its job properly- this happens on the vb and i have to gring a couple of mm of the back of some morese tapers to allow it to seat correctly

 

[kasandrich]

It is worth cleaning your tapers, both male & female. celluse thinnners on a bit of rag would do.

 

[tekno.mage]

My MT2 jacobs chuck does exactly the same and I blamed this on my being a cheapskate and buying a cheap chinese one - actually the chuck part is very good, and I wondered if Chinese MT2 tapers just weren't very accurate. I've been trying to find an MT2 arbor to fit my chuck that is threaded on the other end for a drawbar - but without much success even from the engineering suppliers :-(

That chuck from Peter Child's looks interesting...

Actually, if I want real precision I've now gone over to using MT2 collets with a drawbar - but of course you need a collet for each shank size you are using.

tekno.mage

 

[jasonB]

What chuck mounting taper do you need on the MT2 and I'll post a link for a threaded one.

Jason

 

[tekno.mage]

Jason, the problem I have is that my jacobs chuck is threaded, not fitted using a taper. I can probably measure the thread tomorrow and let you know what it is.

tekno.mage

 

[jasonB]

That will restirct your options.

J