Aluminum baseplate question

[ads (Adam)]

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?

Thanks,
Adam

[gdon_2003 (Guy Donham)]

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.

[Xynergi (HDM Owner)]

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

[ads (Adam)]

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

[ads (Adam)]

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.