Kurt Vise Question

[sanddan]

I have a Kurt D60 vise and wonder how much backlash on the moving jaw is ok. My other vise (Glacern) has a threaded collar that allows you to adjust the thrust bearing preload but the kurt doesn't seem to have any adjustment. The backlash I am talking about is not in the screw threads but in the thrust bearing assembly. The D60 I have has a spiral lock that retains the screw shaft and thrust bearing/washers, no threaded collar. It seems the newer Kurt vises all have this system.

 

[4GSR]

I wouldn't want too much slop. Can't believe Kurt changed it after all of these years!

 

[extropic]

Please load a picture of the area described. I'm surprised to hear that there's no nut (collar w/set screw).

I looked at replacement parts for D60 vises on the Kurt web site and I do see a spiral retaining ring in the D60-KIT. The D60 vise seems to be discontinued.

So, what I understand is that instead of having a threaded collar w/set screw on the exposed length of the vise screw, yours has a spiral retaining ring. Is that correct?

Alternatives (you didn't quantify the amount of backlash or the diameter of the screw shaft)? Thread the exposed portion of the screw and make a custom collar/nut to fit. Or, shim the gap. McMaster-Carr sells wave disk springs and curved disc springs in various diameters and thicknesses. The spring thickness will reduce a gap and the spring action will diminish the perception of backlash. McMaster-Carr also sells shims for shortening shoulder screws in IDs up to 3/4" and thickness down to .005".

I prefer zero preload on a vise screw and as close to zero backlash as practicable.

PS: Spiralock is a registered trade name referring to a special self locking thread form. Spirolox is a registered trade name referring to spiral retaining rings. "spiral lock" is colloquial jargon and not universally understood. Initially, I thought you might be referring to a coiled spring pin, AKA spiral pin.

 

[extropic]

I have a Kurt D60 vise and wonder how much backlash on the moving jaw is ok.

My bad. I didn't answer your question in my previous response.

Answer; it's a hand operated device and 'impact' isn't expected to be a factor. Backlash creates a sort of pumping action when the clearance decreases, then increases. The pumping action can promote the introduction of contamination into places where it's detrimental. Backlash reduces the 'good feel' of mechanical devices for me. So, how much backlash is OK? As much as you can stand. As I wrote above, I prefer as close to zero backlash as practicable.

 

[sanddan]

I'll measure the backlash next time in the shop.

The newest model D688 vise has the same design, a spiral lock instead of a threaded collar. At least according to Kurt's wed site.