Chuck fitting

After some thought I think I’d prefer to re-drill three new holes in the flange if I can. I will test it with a new bit soon. One concern for me was bolt spacing with the flange in situ. I do however have a collet Chuck with threaded through holes so I could clamp this in place and use it as a guide with some threaded guides in the holes. I did also think to space the new holes equidistant with the old but I’m not sure there’s any advantage in this. If I can drill the flange I plan on using hi tensile socket set screws and flanged nuts. My thinking with all of this is that provided the threads are kept clean I should be able to spin the nuts on and off most of the way with tools, just resorting to a spanner for final tightening.

Space the new holes evenly between the old ones and you will always have the choice of two fixing methods.

Spacing the new holes like that was my first thought but it doesn’t matter, I’ll still have the choice no matter where the holes are.

If you plan to mount a 4 jaw chuck at any time in the future, it may be worth having one of the new holes common to both 3 and 4 jaw fixings.

And it means one hole less to drill!i, so that the flange does not start to look like Edam cheese!

By that stage it will have 9 holes in it!, 3 counterbored and 6 new ones for the chucks.

Personally, I would turn up collars for the existing holes and drill the three extra holes for the 4 jaw chuck, fit studs to the chucks, and use nuts.

Howard

All my chucks, 4” 3JSC, 4” FJI, 5” FJI and ER32 collet all have the same bolt hole centres.

Some of the studs arrived today so I tried it out using the existing holes and some flange nuts and it seemed quite secure. Once I can see what clearance I have I may make some top hat washers for the existing holes and see how that goes.