Phil
Great minds and all that.
The issue with using that style of chuck on a drill sharpener accessory for a T&C grinder is body clearance from the grinding wheel.
My Clarkson system handles 1/8" to 3/4" with a 6 jaw chuck having jaws extending 1 1/2" beyond the chuck tapering to about 1/2" outside diameter fully closed. The Clarkson geometry requires 1/2" of drill projection beyond the tip of the chuck jaws to produce a standard 118° point. Chuck body to wheel clearance approaches 1".
Given the relatively large body diameter and zero jaw projection with the Wescott style two jaw chuck it seems that using it on a Clarkson style sharpener to produce a conical point on smaller drills is going to be impractical because the drill point projection beyond jaw support will need to be rather greater. Hence the drill needs to be strong enough to stand grinding loads at the greater projection. My feeling is that 3/8" diameter would be the absolute smallest for satisfactory results.
I see no intrinsic reason why a system couldn't be made with a standard Jacobs chuck with the back drilled out and a tube mount for small drills and a Wescott style for the bigger ones. What's important is the absolute position in space of the drill point relative to the pivots when being ground. Stick out is immaterial except for stability.
Similar body and jaw clearance issues with a four facet system. Obviously if you set things to grind using the lower face of the wheel there will be room for the main body to slip beneath the wheel rducing stick out issues. But it still looks to be a large drill solution.
The layout used by Kaindl to grind on the periphery of the wheel looks more promising **LINK** as that provides clearance for a large and apparently cumbersome toast rack style Vee holder. Which for practical purposes is a naked version of Wescott chuck innards. Would, of course, work fine with an ordinary bench grinder (once someone reverse engineers the geometry!).
Clive
Edited By Clive Foster on 29/04/2020 13:39:46
Edited By Clive Foster on 29/04/2020 13:41:16