Subplate for Thin Metal Machining

Hey Everyone! Long time reader, but first time posting a thread.

I have a Haas VF4SS, and most everything I do is on my 4th axis or on some 6" vices for fixture offsets. I have a need to get into machining some .125" thick steel, aluminum and titanium, and I wanted to make a subplate that could go on and off, getting close to straight and then I can clamp down my metal to that plate. This plate will inevitably have machine marks on it as I will be cutting shapes out of the thin metal. I've attached some pics of a set up I made using MIC6 before that seemed to work fairly well. I was thinking of making something big with a bunch of threaded holes so I can mount clamps to them.

Ideally, I would be able to use this to clamp down some 1" x 1" x 1" cubes that I need to machine all sides on as well. Would be nice not to have to put everything on parallels in my vices.

Thanks in advance!!

My biggest concern if you are cutting shapes out is the part moving and breaking the cutter. Unless you plan to leave a tab, I'd be careful with that.
Otherwise I don't see much of an issue, except for clamping/unclamping the sub plate would take longer as opposed to using a vise.

masonite board

mikecentola said:

Hey Everyone! Long time reader, but first time posting a thread.

I have a Haas VF4SS, and most everything I do is on my 4th axis or on some 6" vices for fixture offsets. I have a need to get into machining some .125" thick steel, aluminum and titanium, and I wanted to make a subplate that could go on and off, getting close to straight and then I can clamp down my metal to that plate. This plate will inevitably have machine marks on it as I will be cutting shapes out of the thin metal. I've attached some pics of a set up I made using MIC6 before that seemed to work fairly well. I was thinking of making something big with a bunch of threaded holes so I can mount clamps to them.

Ideally, I would be able to use this to clamp down some 1" x 1" x 1" cubes that I need to machine all sides on as well. Would be nice not to have to put everything on parallels in my vices.

Thanks in advance!!

View attachment 127103

Click to expand...

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i used to just put 1/8" masonite board or thick card board between part and subplate. i
cut plenty of sheet metal that way. i had a aluminum block about 16 by 12 that would
go in a kurt vise. if part is bigger than vise 6" that i used just regular kant twist clamps
as it would over hang vise and was above table. you could use c clamps but kant twist
clamps fit in tighter spots. i would often feed hold and add or remove or move clamps
i always used 3 or more
.
https://www.google.com/search?q=kan...jnsASr7YDQCQ&ved=0CAkQ_AUoAg&biw=1026&bih=601

DMF_TomB said:

.
i used to just put 1/8" masonite board or thick card board between part and subplate. i
cut plenty of sheet metal that way. i had a aluminum block about 16 by 12 that would
go in a kurt vise. if part is bigger than vise 6" that i used just regular kant twist clamps
as it would over hang vise and was above table. you could use c clamps but kant twist
clamps fit in tighter spots. i would often feed hold and add or remove or move clamps
i always used 3 or more
.
https://www.google.com/search?q=kan...jnsASr7YDQCQ&ved=0CAkQ_AUoAg&biw=1026&bih=601

Click to expand...

Interesting! Those twist clamps are cool. I will have to look into that if I end up floating the subplate in a vice. Should I put 8" Jaws in my kurt vices to help hold the sub plate if I went that route?

Also as far as the parts coming out, I was planning to either use tabs, hot glue or double sided tape to hold them in place.

well look what the cat dragged in... looks like your coming right along on your machining venture Mike. I bet your happy you didn't go with the Grizzly bench top aye?

Look into Mitee bites for that thin plate stuff if you haven't already... http://www.miteebite.com/

A lot of times with thin plate shape work, its best to bite the bullet and build a vacuum chuck... its sort of a venture if your new to it, but ultimately it would pay off if you were going to be doing this work for a while

We use some of this UV curing glue... its not cheap! but it works awesome http://www.bluephotongrip.com/

Kant twists are the bees knees man! As Tom said, they often allow more access to a part compared to a regular 'C' clamp.

+1 on the mitee-bite! You should look at all the mitee-bite stuff - talon grips, versa grips, pit bull clamps, all of their stuff seems to have a nice niche and work very well in the proper application.

I have heard of gluing thin material to a subplate as well, but I have no personal experience with this. With your method I would leave a tab full material thickness, maybe one on each end, and then machine the thickness down at the end to say .01" or so. This way you can easily break the part free and then file the remaining little tab away easier then if it was at full thickness.

I've made a few of those plates with 3/8-16 (thru) holes on 1" centers and 20mm centers. I wound up making strap clamps that were small as I couldn't find anything in the size I wanted. Some were up to 5" long. The short ones I drilled and tapped 3/8-16 at one end for a 1" long set screw in lieu of a step block. They work great for that very first part. Then you're battling ALL the unused holes with clean up. It's amazing how tightly packed the chips can get into those holes! I face milled the surface leaving a shoulder at the back for registering parts parallel to the X axis. And, I usually wind up plowing this shoulder up and have to resurface the plate at some later date. It works, but surely there's something better.

Like Hertz says, if your tool path winds up cutting a scrap piece (drop) free be sure you have it clamped or count on a broken end mill. Or if it's small and is enclosed by some obstruction that won't allow a tiny piece to fly free then eliminate that obstruction, or count on a broken end mill.

Think a sub plate 1/2" to 3/4" thick so still you can lift it and the thickness allows bump rail screw holes to the sides (short and long side) and thick enough to shim under and thick enough to restrict vibration.

subplate

picture of what i use to cut thin stuff or odd shaped parts just using clamps. i usually have
1/8" masonite board to prevent cutting into aluminum subplate which just held in vise
.
subplate goes in vise in about 2 seconds time, clamp on material in about 10 seconds
.
easiest way i know of to cut arc shaped pieces