Seig X2 Self-releasing Drawbar

[Sub MandrelParticipant @submandrel]

There seems to be a lot of interest in self-releasing drawbars.

 

The one below fits my Seig X2. Basically there is a thick washer on the drawbar held captive at the top of the spindle by a hollow cylinder (top cap). Note that the top lockwasher on the spindle needs to be thinned down to expose enough thread for the top cap, and also that the thread is left handed!

 

This one is 3/8 BSW, I keep muttering that I must make an M10 one as well – easy enogh as the top cap will work for both.

 

Neil

 

[Sub MandrelParticipant @submandrel]

[Jim GreetheadParticipant @jimgreethead]

How does this work Neil? Does the top cap just press on the thick washer when the drawbar is unscrewed a bit? And do you have to let the spindle fly up to knock the drawbar loose?

 

Jim

 

PS I still have not made any progress with the “spanner/hammer” – just have to wait for the right size tube spanner to appear in the shop.

 

[Sub MandrelParticipant @submandrel]

There isn’t a moving quill on the X2, the whole head moves. Yes you unscrew the drawbar and the washer pushes against the inside of the cap to release (always with surprisingly little pressure). The drawbar is always loose when not screwed into a taper. The top cap can get tight after several days of starts, hence the small hole in the top – pop in a nail punch and tap with hammer very lightly – much less abuse than tapping out a taper.

 

Neil

[Jim GreetheadParticipant @jimgreethead]

I just had a look at the HM45 and I think it might be possible to rig up something similar to the top cap (or at least performing the same function).

 

It would just be necessary to retract the quill and lock it before unscrewing the drawbar.

 

Hmmm…

 

Jim

 

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