Work Holding Question

[ColoradoSolar]

First off I am new to machining and I have a Supermax Titan mill (Bridgeport clone).

I am wanting to make a square (like a framing square but much smaller) for my wife's glass hobby. It will something like a 4" leg and a 3" leg and be made out of 1/4" aluminum. I want both sides of each leg to be parallel and each leg should be perpendicular to the other. I can't quite figure out to hold it so that I can get to both sides of a leg without it sticking too far out of the vice to where the leg would have too much flex. One idea I thought of while typing this out would be to screw it down to a base plate through holes in the legs and then clamp the base plate in the vice or to the table. That way I could get all the way around the part and it should be firm enough. Would that idea work? Any other words of wisdom that could help me out?

 

[4ssss]

Hang it off the edge of the table and use straps to clamp it down. A quick way to get it square is to put 2, 5/8" dowel pins in the T slots and butt the material against them, hanging the rest off the table and cutting the 2 lengths and then the 2 widths. That should be close enough for what you need to do.

 

[kd4gij]

I would clamp it to the table with a MDF packing to hold it off the table.

 

[Richard King 2]

I would make a Table holding fixture out of either some steel or aluminum say 5" x 4" and clamp it to the table first.

The square you could either make it the size you want from the beginning or make the legs longer and clamp on the longer ends. Then cut or mill off the longer clamp surface when your done. I am assuming you are going to drill a hole on the inside where the angles meet as shown in this square. That way you can mill both inside leg sides in one set up.
https://www.ebay.com/itm/Square-90-...d-Steel-4-100mm-Small-Hand-Tool-/221321070989

With the extra long ends you could also use some Mittee Bite clamps to surround the square. May have to do opposite side at a time when machining
https://www.miteebite.com/products/fixture-clamps/ & https://www.miteebite.com/products/t-slot-clamps/

Mitte Bite has a lot of cool products.

Putting it on a fixture plate, you won't have to worry about milling into the table too. Rich

 

[P. Waller]

You have already figured it out, drill a few construction holes and bolt it to a jig plate then have at it.

This is common practice.

 

[extropic]

First off I am new to machining and I have a Supermax Titan mill (Bridgeport clone).

I am wanting to make a square (like a framing square but much smaller) for my wife's glass hobby. It will something like a 4" leg and a 3" leg and be made out of 1/4" aluminum. I want both sides of each leg to be parallel and each leg should be perpendicular to the other. I can't quite figure out to hold it so that I can get to both sides of a leg without it sticking too far out of the vice to where the leg would have too much flex. One idea I thought of while typing this out would be to screw it down to a base plate through holes in the legs and then clamp the base plate in the vice or to the table. That way I could get all the way around the part and it should be firm enough. Would that idea work? Any other words of wisdom that could help me out?

Your Base plate idea is good. Using countersunk holes in your work piece, with flat head screws, will secure it well. Countersink from both sides (after milling) for a nice look.

To eliminate the issue of having to file out the cutter radius at the inside intersection, finish mill with the smallest diameter cutter you can and (previously) drill a slightly larger (than the cutter) diameter hole at the point of intersection.

Please post a pic or two on the POTD thread when completed.

 

[ColoradoSolar]

Thanks for everyone's feedback.

I was planning on drilling a hole at the inside corner.

I will post some pictures once I get it done. Unfortunately it may take a while because even though the mill is setup I am still finishing up on the rest of the shop and I have people coming to visit next weekend.