how would YOU make these?

I go to 12-step meetings. Sometimes they hand out coins to commemorate years of abstinence. For a long time I've had the idea of making a keyring which would be bored to just hold one of these coins. I finally worked up a design which I've figured out how to make from sheet brass:

formatting link
I make these manually on a milling machine. If there's a better way to make them (absent CNC equipment) I'd love to know about it. It basically boils down to a tricky workholding problem. I have a solution, but I'm wondering if there's a better one. Thus the question: how would you make these parts?

The dimensions aren't particularly significant, but the large hole diameter is 1.354" and the small hole is a #10 hole. The brass is 1/8" sheet brass.

Sorry for the fuzzy picture.

Grant Erwin Kirkland, Washington

Reply to
Grant Erwin
Loading thread data ...

Reply to
JR North

Reply to
Grant Erwin

Grant,

I would stack about twenty sheets of brass and bore the #10 hole then bolt the whole stack together.

Machine all at once as if you did one

Dan

Grant Erw>

Reply to
Dan

Greetings Grant. As others have said you can drill 'em and stack 'em. Absent cnc if you have a rotary table you can stack several rectangles that have been drilled and bored and profile the round part. Cutting a bunch of rectangles and boring them also has the advantage of keeping the burrs small on most of the pieces. With no rotary table you can bolt them to a bar that has a pivot on center and swing this bar on the pivot past the cutter. Make sure you make a conventional cut. The pivot hole should be in a plate with two other holes drilled in it with stop pins in the holes. These pins limit the rotation of the bar. BTW, if you show at the pig roast this year we have folks show up for pig who also go to meetings here on the island. ERS

Reply to
Eric R Snow

Grant,

It's in between the 1.353" reamer and the 1.355" reamer in my set. Your set isn't complete?

Reply to
Peter Grey

I would use a cold header stamp machine.

A place I use to work had dozens of these, stamping out connectors. Usually each machine could put out 100,000 pieaces in a couple of hours.

my 2 cents

Reply to
xman Charlie

MSC has a 1-3/8 reamer. Anybody with a cylindrical grinder can reduce it to 1.354 It might make more sense to spend the money on an adjustable boring bar. That would be more useful for other projects.

Reply to
Chief McGee

I use a boring head now. With practice, I can get within a thousandth of what I want that way.

Grant

Reply to
Grant Erwin

Grant Erwin wrote: the question: how would you make

Well, you asked. I don't have a milling machine. I would start with a bar, shape the outside profile with passes in the milling vise and a file, chuck it in the four-jaw, drill and bore the holes, and cut them off like washers. If I had a mill, I would shape the bar with shaped cutters(I'm thinking horizontal here) or mount the bar in index centers and take multiple passes to shape. In the mill, you could mount a saw on the spindle and slice them off like cordwood.

Kevin Gallimore

Reply to
axolotl

Reply to
JR North

Lasercutting Northwest in Auburn. Well you asked!

Reply to
Ernie Leimkuhler

Reply to
R. Wink

Same as I was thinking, or waterjet.

Lane

Reply to
Lane

How accurate are parts cut by laserjet or waterjet? If for example a hole is specified to 1.000" does it need to be cut slightly undersized and then reamed, or can they cut it within .001"?

Grant

Reply to
Grant Erwin

I have no first hand knowledge, but have heard that it is very accurate. The width of the laser beam and/or water stream is very precisely known and controlled.

I'm sure someone with more intimate knowledge will chime in.......

Lane

Reply to
Lane

Depends on the material and thickness and, like anything else, the machine and the operator. I've had parts laser cut from 11ga SS with holes burned in that were then tapped

6-32. The first batch I called the holes out undersize and then cleaned them up with a drill. After seeing how close to the print they were, had the rest cut to size and had no problems. I don't recall exactly, but they were better than +/-0.005 on a .107 hole.

Ned Simmons

Reply to
Ned Simmons

Omax claims +/- .002 for any 12" movement with a repeatabilty of +/- .0013. This will vary some depending on material thickness though.

Craig C. snipped-for-privacy@ev1.net

Reply to
Craig

They used a flowmaster (?) on AmericanChopper and Vinney found the cut was slightly angled which required some grinding on the part to make it fit. Not sure if that's a setup issue or just a feature of the tool. If so, I wouldn't call it accurate.

Joel. phx

Reply to
Joel Corwith

Check out the Omax tutorials on water jet technology.

formatting link
Seems to have been written by someone that loves what they do, instead of the typical marketing BS you get.

One of the topics covers tapered cuts and how to avoid them. Very interesting stuff :)

Take Care, James Lerch

formatting link
(My telescope construction, Testing, and Coating site)

Press on: nothing in the world can take the place of perseverance. Talent will not; nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts. Persistence and determination alone are omnipotent. Calvin Coolidge

Reply to
James Lerch

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.