Setup and machining of part

Hi guys, wondering if anyone had some insight on how to progress with this part.
Its basically shaped like a magnifying glass, round with a handle off the bottom
Round part is approx 1.5" with wall thickness of around 0.120"

I'd like to do these out of plate with multiple items on the vise at one time, the issue is how to hold them etc.
All sides will need to be machined
I can only think of using tabs and flipping for the back, but given that I want to make say 100 of these, tabs are going to be a pain in the ass to clean up

Any insights?

If I'm picturing it right I would machine out the center, Place a bolt through a turned 0.375 plug that covers the entire center and screws into the fixture. Then machine the outside. Unless there is crazy complex stuff you are doing on the back I would machine 2 sets of soft jaws (one on each vise) and load them in after machining them all to finish the back.

Brian
WOT Designs

Thanks for the reply
Basically I'm trying to make something very similar to the below from another member here.

Hope they don't mind me stealing the pic for an example :)

http://i132.photobucket.com/albums/q...2/IMG_2376.jpg

Probably not what you want to hear, but perfect for laser/water jet cutting and finish on the mill afterwards - certainly for the 100 or so that you want to make.
Other than that I'd probably do it as Brian says.

I've sort of worked out in my head a fixture using the centre to mount off after doing the inside as mentioned by WOT

Now if this part also had to be split with either 1 or 2 screws like a rifle scope ring for example what would be the best way?
I can envision stacking them all together and clamping in vice and drilling and tapping etc screw hole, then having to remount singles to then cut with a slitting saw
They could be slid onto an arbour and done on a 4th axis I spose but not looking at way yet

Or?

I love places like this as everyone has a different idea and more often than not you can pick bits out of a couple of ideas and really come up with a good outcome.

How to hold for the back side facing and chamfering without crushing? Hmm

I would make a fixture. Leave the fixture in the vise. For each piece of new stock clamp it to your fixture, drill some holes at the ends and some in the middle, use screws through these holes to hold to fixture. Do all ops on one side, leaving tabs plus finishing stock on the outside perimeter. Flip part on fixture and re-secure with screws. Do the rest of your ops on the back side, leaving the tabs. Use plugs like WOT said to hold parts to the fixture while you remove tabs and finish the profile. You'll only need to reference once as long as you keep the fixture in the vise.

If you can do soft jaws that may be easier yet being you wouldn't need to use screws.

As for slotting and doing the clamp holes, I would make an arbor to hold them in the vise to do as many as you like at once. You would need to find a way to clock them all properly, maybe lightly clamp the tails in the vise when you put the arbor through and lock it.

Thanks for the reply

Leaving tabs makes total sense, not a train of thought I was in as the idea is to get rid of tabs at the end, but as an intermediate step, perfect I think

Would make a couple tool changes needed as chamfer on inside would have to be done before then centre washer clamps were fitted, and then tabs removed and outer chamfered, but other than a min or so down time to change tooling, seems like that is the way to go

I think I would put a plate long enough to make 4 or 6 parts, held on a plate that has adequate screw holes to hold the strip. Hold it down with about 8 or 10 1/4-20 screws and machine the center hole and the slot complete. Then in the same set up, I would put a thick clamp (maybe 3/8 thick, held on with a 5/16 or a 3/8 SHCS) on the center of the parts and then machine the outside complete.

Machine from the back leaving 60 thou thick skin outside.
Flip over, machine the top.
Mill down outside leaving 20 thou skin.
Then break the toolpath to create tabs with the smallest possible endmill.
I would use 3/32 or even 1/16.

Get a flat strip of steel that fits in and knock your tabs out.
Attachment 202732

On second thought, I think I would start with material that is about 1/8 inch too thick. Hold your strip of material in a vise and machine the top of 4 to 6 parts complete, then, cut them apart in a band saw. Next, machine a set of soft jaws to fit your part, loadone part on each end of your vise and finish machine the second side.

You might even consider doing a little flip flop to get more parts out of the same chunk of material.

I would probably do the whole job with a 3/16 end mill with the exception of the little slot in the handle.

That's not a difficult part.