Tall Angle Plate Project | The Hobby-Machinist

All my angle plates are on the smaller side so when trying to mount something like an electrical box that is bigger than one of the angle sides and with mounting tabs plus cover it becomes awkward.

During a recent visit to the scrap yard I saw and adopted a piece of machined cast tie bar that reminded me of a special “Tall Angle Plate” tool I have had in my head for a while that should prove useful for odd shaped projects like an electrical box. The piece of material, shown setting on the mill table in the photo below, is about 14 inches tall and 4 ¾ inches wide.

The bottom leg is 5 inches long. The two angle legs are machined but painted on the outside but other surfaces are as cased except for the sawed top which will be machined to clean up. Now I just need to figure out the best way to mount the tall angle plate to the mill table and finish the project. The web of the casting is over the center groove of the mill table in the attached photo but will probably need to be over the table between two of the table grooves in use.

Anyone have suggestions for the best way to finish the tool project for the most versatility? I have time to think as no immediate need is on the horizon and the shop is till cold.

Benny
The Orphanage Never Closes

What you are making is called a TOOL MAKER'S KNEE. That piece is a most excellent object to make one from!!!! Could hardly be more ideal.

I strongly advise you to NOT try milling the top of that tall object while it is bolted to your mill's table. It might jerk so badly it could jerk a hole right out of the T slot on your milling machine's table. That would cause untold grief for you.

The top surface of the angle plate has no need to be accurately machined square. If it were mine,I'd saw the top off with my bandsaw a bit to get rid of the dollop in it,and grind it smooth on my belt grinder. If you are good at grinding,it would look quite acceptable.

If you MUST machine it,I'd clamp the angle plate down horizontal,resting it on the back web(securely clamped down),and machine across the top of the uppermost web. Then, clamp the plate on its side,and machine that back web down. You could just machine the back web to be lower that the front surface,because it would be extremely difficult to blend the 2 cuts perfectly. You'll need a long cutter to machine the center web,so it won't be the easiest cut to make,and you'll have to take light cuts or risk breaking the long end mill.

Heed my advice in any case,you don't ever want to try milling a piece of metal that tall,with that small a base on it. I could suggest bolting the base to a much larger piece of THICK steel plate,and using 4 T nuts to attach it to the table. But still,your table is cast iron,which is not the best metal to resist shearing forces,so I would still do the job with the angle plate laying down.

If you have a large enough lathe,you could actually do the job of truing up the tall ends more safely on it. Clamp the base of the angle plate in a 4 jaw chuck,seating the base firmly against the chuck's face. Drill a center hole in the other end. Face off the other end as much as possible while it is supported by the tailstock. Get rid of the dollop in it. You could get reasonably close to the center drilled hole,and grind,then file it away later.

To do the bottom of the ang. plate,reverse the A.P. in the lathe,and face off its base's surface. A drilled center hole won't hurt the accuracy of the plate,though you'll still have to carefully grind,then file away the area around the center hole.

After you have done these 2 surfaces,you can clamp the plate horizontally in the mill. Use a precision square against the base,and possibly shim up under the web of the plate to get the plate square. Then,mill the tall surface.

This is the best way I can think of this morning!! Maybe Tony Wells or someone else can think of a better solution.

A possible solution to your challenge - mill a squarish hole across the web of the angle as shown, and drill a clearance hole for one of your T-slot studs thru the base on centerline underneath the cross hole. …………….........Use two other hold-downs (in the "outer" T-slots of the mill table) to secure the bottom plate opposite the front web. This should hold the angle plate securely and keep it from rotating on the first stud.

Thanks John,
I like your idea of one t-bolt on center and two clamps on the bottom flange. I wanted it on center but abandoned the idea too quick and was thinking two clamps. Three hold-down points would be better.

What drawing program do you use, the illustration is great?

What you are making is called a TOOL MAKER'S KNEE...............

Thanks George,
It is always good to learn the correct terminology for the hobby. Machining the top is not too high a priority for me but I may try. I will keep your setup and machining suggestions in mind when I perform the cleanup and mounting provisions. First I must remove the paint get the shop warm. Hopefully this week the last cold front is passing through.

Is there another piece of that over there? If so snag it for me or hide it somewhere til I can make it back over there………..

Sorry Charley,

There was two ends to the bar but being cheap like I am, I cut one end of the tie-bar off to reduce my cost for the material. Another guy at the yard asked what I was going to make and liked the idea and grabbed the drop to make one for his self. It had a little damage but he was not concerned and said he could clean up the damage.

Benny
The Orphanage Never Closes