Reaming question

[jimbo_cnc]

Thanks. I suppose mild steel counts as hard?

If so I'm looking at the 5 steps of reamer,

or I see what happens with a drill. I'm not hopeful, but I'd better try it.

[EddyCurrent]

If so I'm looking at the 5 steps of reamer,

You could use an adjustable reamer that covers a range of sizes.

[mekanik]

They are a bit fiddly(if that's a word) with the job clamped it's just drill & ream.
Mike

[jimbo_cnc]

Thanks for the jig design. This will be my first metalwork jig.

I like the dolly in the chuck plan. But I might be doing 50 or so at a time and I'm wondering if I can avoid taking the drill bit in and out.

If I bring the 6.9mm drill down onto the 6.5mm hole, that might centre it OK, do you think? I could position the strongback manually or slip a length of tube over the drill bit.

[EddyCurrent]

What about something like this, a counterbore with pilot, the problem will be getting the sizes you need;

http://www.arceurotrade.co.uk/Catalo...s/Counterbores

[mekanik]

Thought i had just posted a reply but i must have dicked up.
make a base plate for the underside support from 10mm plate long enough to be able to clamp to your table, you now want to drill a couple of holes the same dia as your mount securing holes, push in a couple of pins to locate the mount.
Now drill and tap two holes for the strongback clamping studs, if the holes for these studs are same size as the studiron this will bring the strongback on centre so all you have to do is allign the jig ie mount located and drill in chuck then clamp this to the table so it's undo strongback next please and repeat 50 times.
Have fun
Mike

[jimbo_cnc]

That'll do it :) thanks.