Speed of 4jaw chucks

Came across an post recently regarding the safe speed for a 10" 4 jaw chuck or a 10" faceplate,so I decided to check to see if there were any markings on mine [ex Chester ]. Needless to say,there are none [no surprise there],so it seems to be a case of using that rare gift,common sense.

On the other hand,you can buy a saw blade in Lidle,s for 7 Euro with it,s max speed clearly stated Nuff said !

Normally the speed of the chuck is limited by the maximum design speed of the lathe it was made for, this of course doesn't allow for electronic speed control modifications to old lathes that can increase the speed.

Ian S C

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High on the list of maximum speed must surly be how well balanced the setup contained in the jaws is.

Nick

You need to look at original manufacturers data for the chuck. You might be surprised how low some max speeds are.

I might do that,if there was any data to go by,as I said there is nothing,so I just use common sense and start with a low speed and see how it goes. The danger is that someone with no experience will not know any different and just lash away. Chucks supplied with lathes come with no directions of any kind,I think they assume that you know what you are doing,which is all too often,far from the case. A simple stamp would be a great help.

I remember Sparey mentioned that you might be surprised how often you have to use back gear. How right he was !

Bit of a sweeping statement, my chucks have max rpm stamped on them, even the imports.

J

i worked on a Antonio Anselmi lathe with a 18in. 4 jaw, and on the machine is a warning notice "max speed on the 4 jaw chuck 270 rpm"

Probably the limiting speed is not that at which the chuck body shatters, but the speed at which the jaws become detached. After all there is, comparatively, very little metal holding each jaw in place. Just a fork on the back of the jaw engaging in the adjusting screw.

To shatter a 18 inch cast iron chuck body, it would have to be rotated at several thousand rpm.

Automotive Products near Leamington Spa had a rig for burst testing things like Flywheels. It needed a 6 cylinder Jaguar engine, with a step up belt drive, to wind things upto bursting speed. The bang was quite dramatic (No one allowed in the test cell, with the item on test in an iron pot set into the floor) and even after the time needed to unbolt the cover, the remnants were still too hot to touch!

Howard

I think maximum speed is to do with deformation due to centrifugal forces as well as material strength. Watched a YouTube video recently, can't remember what chuck company it was, it showed the loss of holding force as the speed increased with a hydraulic power chuck. Also I remember ARC recalling chucks recently that had deformed due I suppose bad design/material.

It is unfortunately, I don't have one on my 8" import. I reckon I wouldn't want to take it very fast anyway. The off balance nature of what you normally put it one makes it quite risky.

Michael W

Counter balance weights, simples.