How do I make this?

[Mr Ron]

Class B1 Switcher.jpg (5.19 KiB) Viewed 4323 times

I have to make 12 of these. The material is 6061-T651. My concern is the 0.077x0.250 slot. I will need to use a small end mill. What should I use? a carbide or HSS end mill? I'm thinking a 1/16" end mill will work. What is your recommendation?

[GlennW]

The drawing is too small to make any sense out of for old guys like me!

[DavidF]

I cant reall see the drawing either, but I would recommend broaching it....

[NP317]

Use a slitting saw for small slots like those.
~RN

[Mr Ron]

Spring hanger.jpg (6.79 KiB) Viewed 4286 times

I don't have anything to broach with. The slot measures 0.077x 0.250 and is 0.250 deep. This picture should be clearer.

[DavidF]

Its just aluminum, im sure you can make something work to broach it...

[Harold_V]

My money says a slitting saw. You could also use a Woodruff cutter, assuming you can get one large enough in diameter to permit the depth of cut required. Width isn't much of an issue---you can step over, using a 1/16" wide cutter. If it's sharp, it won't have any problems at all taking the second pass (it won't deflect). You can control width by raising and lower the knee, assuming your mill is so equipped.

Assuming you have a decent vise, you can hold the piece at one side, extending it far enough to make the cut without hitting the jaw. By clamping a stop, you can hold depth consistently without worrying about the location of the part. For small work such as this, I have a series of ¼"-20 tapped holes immediately behind the jaw insert on the fixed jaw. Those holes allow me to clamp stops where required. They can also play a role in holding parts down against parallels when you are machining thin pieces that can't be clamped too tightly.

This is important, assuming you try what I suggest. Place a second part at the opposite side, so the jaws remain dead parallel when tightened. If you don't, the piece you hope to machine will be VERY easy to move, and will most likely be ripped from the vise. With a second piece in place, that won't happen, and you lower risk of damaging the part by chucking pressure.

H

Edit:
I'm assuming you are discussing the open end slot, not the small one that has square corners. If not, please disregard what I said. It's not clear to me which you are discussing, and the enlarged view lacks dimensions, so it doesn't help.

[Magicniner]

I'd make a tool steel broach for the small slot, mill the slot to width and broach the round ends square in the press.

[Mr Ron]

Edit:
I'm assuming you are discussing the open end slot, not the small one that has square corners. If not, please disregard what I said. It's not clear to me which you are discussing, and the enlarged view lacks dimensions, so it doesn't help.

My apologies to all for not being more specific about my plans. i'm trying to multi task with designing, writing and battling with my lack of computer ability. The problem I'm trying to address is how to mill the small rectangular hole at the bottom of the figure. One way would be to drill a number of small holes and finish the slot with needle files. The slot is to receive the ends of a leaf spring for a loco I am building.

[earlgo]

I would go with Magicniner's suggestion. I did a similar thing with a steel replica of a S&W rear sight slot. It came out very nice. Instead of a full width broach you could make a short one and square out the corners on one end of the slot, then the other. Your mill quill should have enough oomph to do this in aluminum.
--earlgo

[whateg0]

I agree with making a small broach. I have in times past made the part in two pieces. with the "slot" left open. Then weld in the part that encloses it. Don't know if that will work here or not, since the aluminum will lose its temper when welded.

Dave

[whateg0]

Also, mrpete222 shows how to use a mill as a shaper for things like that. You could make a small tool to fit into a special holder on the mill and knock those out pretty quick.

Dave