- Joined
- Jul 28, 2017
- Messages
- 2,368
I'm in the beginning phase of making a tooling plate for my benchtop mill. I flattened the plate with a fly cutter (it was warped and rocked on the table) and am now making the mounting holes for the plate. They are counter bored to place the bolt heads below the top surface.
I'm planning on making a number of low-profile work holders similar to what Harold Hall describes on his web site, but a thought occurred to me. If I bolt the work holders down using more counter-bored holes there will be a lot of possible variation in the alignment of each holder -- so in addition to aligning the tooling plate when it's installed, I will likely need to align each of the holders -- at least, if I'm milling some critical dimension on the X and Y axis. If I'm just thinning something down then alignment is not an issue (but the first thing I want to do DOES require good alignment on X). Anyway, I was thinking that if instead of counterboring, what if I countersink the holes and use flat-head bolts. The cone recess and cone-shaped bottom side of the bolt would force alignment between them ... at least to some degree. I THINK it would be better than a counter-bore.
So have folks here used this approach for the purpose of improving alignment? And if so, how did it work out? Is the manufacturing tolerance of the bolts too wide to make this a useful approach?
I'm planning on making a number of low-profile work holders similar to what Harold Hall describes on his web site, but a thought occurred to me. If I bolt the work holders down using more counter-bored holes there will be a lot of possible variation in the alignment of each holder -- so in addition to aligning the tooling plate when it's installed, I will likely need to align each of the holders -- at least, if I'm milling some critical dimension on the X and Y axis. If I'm just thinning something down then alignment is not an issue (but the first thing I want to do DOES require good alignment on X). Anyway, I was thinking that if instead of counterboring, what if I countersink the holes and use flat-head bolts. The cone recess and cone-shaped bottom side of the bolt would force alignment between them ... at least to some degree. I THINK it would be better than a counter-bore.
So have folks here used this approach for the purpose of improving alignment? And if so, how did it work out? Is the manufacturing tolerance of the bolts too wide to make this a useful approach?