How would you make this part? (in Aluminum)

[SRT Mike]

This part is driving me nuts on the best way to make it. It's so simple a part, it seems.

The tools I have available are a 2-axis CNC lathe and a 3-axis VMC. I need to make maybe 200 a month or so.

There are 2 parts.... As you can see from the pics it's just a basic ring clamp that goes on a bar. The ID of the ring is 1" and the OD is 2". There is a top and a bottom. The idea is they clamp around a 1" bar and 2 socket head cap screws go in and hold it together - then something flat can be mounted on the top.

I was thinking the most efficient way may be to start with 1"ID/2"OD tubing, mount a section in my milling machine and just use a big honking face mill to mill off the top half. Then I could come up with a fixture maybe using mitee bite clamps so I can machine the holes from the top on the one part and the holes + flat on the top on the other part.

But cutting them out on the mill would be a bit of a PITA.

Or I could cut the "C" shaped parts out of 1/2" plate but then how to fixture them to cut them out? That would be a PITA too.

Or I could turn rings on the lathe that were already neatly sized, but then I'd need a fixture to hold them while I face mill them in half, then I'd have to turn them over to machine the other side.

It seems like such a simple part... any ideas?

Oh, and on the one with the flat, I can add a counterbore to the through-holes on either side (because I am sure drilling from the top without a counterbore would cause the drill to wander and break).

[JWB_Machining]

I would go about this in a way where unless you're able to cut super accurate on a band saw or cut off saw is perfect you're gonna end up wasting about 45% of your stock.

1) Start with 2" od 1" id tubing and part it of to the lengths you need.
2) Cut these in half two make two Cs, this is where if you're perfect you can get two if not you only get one out of this section of tube.
3)Mill a profile of this part in soft jaws so it's held well in my vise and face it till it's the perfect half ring you need, measuring this will be a pain but if you mill your soft jaws right you'll know where you need to be.
4)From there I'd drill the holes, 2 for the one 4 for the flat part.
5)use a Different vise and turn the parts of so they're sitting on the side you face milled. I'd then use a 2 flute end mill to plunge the location of where the bolt heads will be. And for the flat ended parts i'd face them down.

Sorry if this is confusing if you need clarification on anything feel free to ask.

[Gary55Ford]

Why don't you just buy 2 piece shaft collars and mill the flat on 1 half?

[Geof]

Use rectangular stock that will allow you to grip as long a piece as possible across two vises with enough material protruding so you can fully machine the ID and OD.

Now you have a length of bar with maybe three or four sets machine in it.

Then make a simple fixture so that you can hold this full length in the vise to do the holes. NOTE you will have to machine the two halves alternately up and down in the first operation so you can do the counterbore on the top and tap into a flat face on the bottom.

After the holes are done cut the sets out on a band saw; do not separate the sets,

Make a set of custom jaws for the vise to grip between the ID and OD.

In the custom jaws face of the excess material that was used for gripping in the first vise operation and you have your complete halves.

We make an almost identical part and I can see if I can dig up photographs of our setups if this description is not clear.

[idaho psycho]

I just made a similar clamp 2 days ago. I wish that I could make 200 a month, this was just for a run of 40.

anyway, the way I went about it was to place a block of flat stock in the vise on the left that was .125 thicker than the part then mill the profile out of the top of the block, leaving a flat piece on the bottom. I made the soft jaws on the vise to the right. the soft jaws hold 2 pieces, the left side holds the profile of the piece just cut out in the left vise, the right side holds the piece in the vertical position for drilling a tapping, and profiling the radius on the end of the piece. Its not much of a pain to make the soft jaws. It does waste stock, but its only a six minute part. This way the parts move from left to right, you just keep moving the part to the right and pull the finished one out. hope this helps. have a great day. I can send more pics thru email if this helps.

[Geof]

I just made a similar clamp 2 days ago....

Obviously we are not the only ones doing it the correct way.

The only difference is we do six parts per machine load and that cuts the time per part greatly because of the saving in tool changes.

[Kipper]

I just made a similar clamp 2 days ago.

Nice work!

[idaho psycho]

If i knew i was going to be doing more, i would do like geof mentioned and set up for it, thanks for the comment on "doing it right" by the way. 40 is such a short run, if had set up to do more it would have been more effecient, and that's not really how stuff seems to work out around here... It would go against the grain of screwing up, trying again, scrapping that idea, trying a new idea, repeating the screwing up part and eventually not making any money on time, but just out sheer determination and will power finishing the part, not for the money, but just because you said you would.... I try to avoid that, but it does happen from time to time. good luck with the parts!

[Geof]

I dug out a few pictures from our setup instructions; more or less self explanatory.

[Khalid]

geof..thanks for sharing the info..

[rfwyzard]

Bar stock as close to finished size as possible. Cut to length. Drill and tap half the pieces, drill and counterbore the other half and mill the top flat. Bolt together and bore centerhole, clamp hole in lathe chuck and turn OD or use hole to clamp in mill and cut OD. Machining part, then cutting in half and surfacing joint face is a waste of time and material.