better way to tackle this part?

Jason Harris · Sep 11, 2006

Hello all, I have a simple problem which is to make two rings about 125mm ID and 133mmOD.

I have solid round to do this from. Last time I did this I had to bore out the solid until I could part off two rings. What a waste as well as taking time to do it..

Any other suggestions that might not leave me 90% waste? the solid is only 100mm (4") long so I could with the right holesaw cut out a big plug for use on something else and then just bore out what was left.

I dont have that holesaw though.. Any other ideas?

Thanks,
Jason

dmalicky · Sep 11, 2006

5" sch. 120 pipe has a smaller ID and larger OD than your dims, if you don't mind starting with a different blank.

Jason Harris · Sep 11, 2006

Ahh yes, that would be too easy

I am doing it out of aluminium and none of my local suppliers have any tube/piping of a similar dimenstion. I wish it was that simple for me

Thanks,
Jason

Evan · Sep 11, 2006

You didn't say what depth the rings must be but if not too deep then it isn't hard to carve out an annular bore giving sufficient room for a boring bar to finish the ID while leaving a substantial core for later use. I have done similar and on one project made a series of 9" OD x 7" ID rings from 1/4" plate on a faceplate. I was left with disks approx 6" OD.

Jason Harris · Sep 11, 2006

Good point, the rings need to be about 19mm each which means I need about 1 3/4 " deep in total.

Thanks ,
Jason

Evan · Sep 11, 2006

Keep in mind you can finish the id after you part off the piece unless absolute concentricity is important. You also can do one at a time and when the first is parted it will make access to deepen the annular bore easier.

willbird · Sep 11, 2006

You can make a tool from steel tubing with some Hss brazed in, MY dad made one like that many years ago, basically a big home made single tooth holesaw, he used carbide because he was cutting steel, but on alum Hss would work fine, just silver solder it into a notch, and grind it nice and sharp, provide some Id and OD clearence so the cutting tooth makes room for the tubing body.

Bill

Jamie · Sep 11, 2006

Jason;
I had almost the same problem once, had to bore
a 3.750" ID in 3 x 3/16" AL 6061 plates. I
stacked them and drilled a hole through all 3,
then I removed the blade from my scroll saw at
the upper arm, passed the free end of the blade
through the hole I drilled in the plates, then
reattached the blade. I was then able to rough
cut the ID with the scroll saw, then finished
the bore on the lathe.
Jamie

bluchip · Sep 11, 2006

19MM is not that deep to trepan...esp since you have such large area to deal with. Make a trepan tool from a 1/2" endmill shank ground to half flat, trepan to say 21mm deep, this will leave a 1/2" wide groove that you can get a small boring bar in then bore, then part only til ring falls off. Leave the plug to line up on again. Repeat til the plug hanging out gets unweildy then saw it off or chuck on it and do the other end.

metlmunchr · Sep 11, 2006

If you were going to make a lot of them then it might be worthwhile to trepan or otherwise remove and save the center, but for just 2 rings its not worthwhile unless your time is free.

Roughing the bore will go a lot faster if you use a bar that will cut on the side as well as the end. A bar with a CNMG insert, for example. Once you drill the starter hole you can open up the bore via a few transverse passes instead of a bazillion short boring cycles.

Jackmo · Sep 11, 2006

metlmunchr,

I would rather take boring passes then tranversing, I think you could take a heavier chip because the pressure is toward the chuck rather than to the side. I agree a good insert boring bar is best.

Another thing is to r. circle mill it on a CNC mill, if you have one.

I think he just hates to see all that good mat. turned into chips.

Jackmo

Forrest Addy · Sep 11, 2006

How fancy do you want to get? How about cold swage 5 IPS sch 40 pipe to 5 1/4" OD 113 MM)? It should take two passes so you'll need to make two swage rings. It's aluminum so a mild steel rings and Murphy's Oil Soap will do the job. Polish the throat mirror bright and relieve the chase. A 20 ton press should be plenty. Anneal before swaging.

The pipe ID should upset slightly and finish leaving you with plenty of stock.

How many parts? One batch from one slug? Waste the bore of the slug. A 4" Dia x 4" piece of free aluminum isn't work the bother.

Personally, I'd turn the OD and face, then trepan and part odd rough rings, finishing the bores and opposite face in soft jaws.

Peter S · Sep 11, 2006

Jason,

I would just drill with largest possible drill bit to the depth of the two rings (ie 45mm approx) and then bore it out to size. Not much waste really. Everything will be concentric.

Trepanning can be a pig of a job. The main trouble I have had is in steel, not being able to get my lathe to run slow enough for HSS on large diameters. Unless you particularly want to experiment with trepanning I think I could have it drilled and bored out in the time it takes to make and set up a tool.

wiz · Sep 11, 2006

Funny I have two rings to make too.

I started with two pc of hollow bar 7.5 od 6 in id. fibish od 7.086 id 6.711 with an internal flange. when I chuck it up in the 3 jaw chuck I relised it would have been a lot easyer to make it out of sold and throw away the id. material is cheap. the rings flex when clamped. now I'm making a plug to support the id of the ring. I may just start over. I need to hold a few tenths on od and id.

the solid would have been cheaper and easyer. Maybe. As soon as I get the rush job out of the way I'll regroup and get it done. $h!t happens.

was

wildwilly · Sep 12, 2006

wire edm, aluminum cuts pretty fast.A start hole
near the edge of the ID and you will have minimun
waste. But the material is cheap and the process isn't.

Carl Darnell · Sep 12, 2006

I too think drill as big as posible and use boring bar with HHS, 15-20 deg back rake and polish the top of the tool. Use kerosene to lube it and rough it fast and take nice finish cuts. If you have a local company that has a liquid abrasive machine they may be able to cut the center out but the price may be to much if you are close on the bid.

Rustydog · Sep 12, 2006

What are the names of a couple companies that carry a line of trepanning tools?

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better way to tackle this part?

Jason Harris

Aluminum

dmalicky

Aluminum

Jason Harris

Aluminum

Evan

Titanium

Jason Harris

Aluminum

Evan

Titanium

willbird

Banned

Jamie

Hot Rolled

bluchip

Stainless

metlmunchr

Diamond

Jackmo

Hot Rolled

Forrest Addy

Diamond

Peter S

Diamond

wiz

Cast Iron

wildwilly

Aluminum

Carl Darnell

Titanium

Rustydog

Cast Iron

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