Aluminum baseplate question

In seeking better workholding, and lacking a low profile vise that didn’t take up too much Z-height, I designed and milled a vise.

I mounted the vise to an MDF spoilboard with brass threaded inserts (my standard workholding) and used a dial indicator to see how much the fixed jaw moved on clamping, getting ~.015" movement just cinching down.

There are two obvious causes of the motion. First, the only spoilboard SHCS screws I had that were long enough were nylon… I’ll be sourcing something else there.

The second point, though, is that even with a rigid SHCS the inserts are going to move some in the MDF. I’ve looked at aluminum baseplates for the SO3 XL, but that comes to $650 + tax and shipping, which I’m hesitant to invest (it’s been a while since I’ve crashed into the baseboard, but I’ve made my mistakes…). Instead, I’ve got an ancient piece of 0.5" thick 2024-T350 that’s 21"x32". It’s currently sitting unused as the base to an old dolly. Any thoughts on repurposing that piece as a baseplate?

Three things:

  1. Is 2024 going to surface well on the SO3? I’ve cut aluminum, and I mostly use single flute end mills. I saw the other discussion about 2024 from 2019, but it was speculative. Has anyone cut 2024? Does it chip or gum?

  2. I’ve trammed the SO3, but it seems I never fully get rid of the little step one finds when facing. I don’t know if that step can be trammed away or if that’s too much to ask from an SO3 with a Z-plus. MDF is more forgiving of those little steps.

  3. If I was to make the spoilboard out of the piece of 2024, any recommendations on what to add besides a pattern of threaded holes? Should there be dowel holes, too?

Any recommendations from those with more experience under their hats?



Since you are drilling anyway why not make dowel holes. Most people use the dowels for 2 sided milling. So if you are going to make 2 sided designs why not get the crying over in one step. If you are not planning for 2 sided jobs then the dowels would be a waste of time and in the future if you change your mind you could always machine them in then to fit your particular project. So 6 of one or half a dozen of the other.

Nice Looking Vice.

Your vise looks awesome. How did you cut the threaded holes? Did you do it via CNC or hand tap them?

Good point. I could put standard dowel holes in the table that fit the locations of swappable fixture plates.

The threaded holes on the top for the set screws and for mounting soft jaws were located and started with CNC, but I had an issue with the 1/8" single flute not appreciating the hole depth of the small minor diameter, so I finished the hole by drilling and then tapped manually. For the ACME screw, you can’t see it in the photo, but there’s a cavity in the backside for a captive ACME nut so that I wasn’t relying on aluminum threads for clamp force.

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