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Adhesive work holding.

First question...
I want to make a ring from 3/4 thick steel, 7.500, 6.000id.
Seems if possible, glueing it to an aluminum sacrificial back plate and turning it would be the way to go to ensure concentricity.
Would that work?
 
A 4-jaw chuck on the lathe would do a better job. Hold it by the I.d.(can use a 3-jaw) turn the o.d., then hold the o.d. with a 4-jaw and dial in concentricity to do the bore.
 
Are you gluing the steel plate to the aluminum back plate just to hold your work(I assume)? Is the 6" bore cut prior to gluing? If the bore is there prior to chicking why not chuck on the ID assuming your using a lathe? Yeah the glue would work of you want to face and bore, but take it easy on speeds and feeds. For a part like that I wouldn't do it. Instead you could center drill a 60 degree countersink and press it to the jaws or a flat faced arbour deal live center or turn in between centers,machine OD, then re-chuck on OD and machine faces and ID bore. Or chuck on OD, machine bore, re-chuck on ID and machine OD. That is assuming your using a lathe, but you could do it all the same way on a mill with a lathe chuck.
 
Clamp forces will distort the ring.
Clamps will interfere with indicating the surface being clamped.

Lighten up the clamping pressure and take lighter cuts. Or you could make it from thicker stock and part off.

I wouldn't think you could hold onto it well enough with an adhesive to allow you to turn it. I've used a fair amount of double sided tape and some super glue for cutting various woods, plastics, and small metal parts. They work great but the material needs to be soft or you need to to take light cuts.
 
If curiosity drives you to try I would at the very least run the tailstock up to "catch it" if it did come apart. From what ive seen of the process none was over about 3' in diameter and it was solid not a ring so a lot more surface area.
As AARONT said make from solid and part off. Ive done some similar for spacers for bearing and the like.
 
Thanks.
It still seems to me that clamp forces would distort the part.
It also seems seriously wasteful and expensive to make a ring like this from a solid, and I can’t find DOM that size.

Thanks for the answers.

Back to the topic.
Double sided tape and cyanoacrilate seem to be the adhesives of choice.
Any others in use?
 
First question...
I want to make a ring from 3/4 thick steel, 7.500, 6.000id.
Seems if possible, glueing it to an aluminum sacrificial back plate and turning it would be the way to go to ensure concentricity.
Would that work?

.
had a steel part using hot melt glue to aluminum block did my machining and part was slightly warm so i take it to a sink under cold water and it falls apart. temperature difference with a brittle glue you often get no warning on bond failure
 
Gluing a part to a mandrel is a necessary step for some parts, ive done it. Not for production, for a few one off's yes. Perhaps there are other ways, a fast paced project requires creativity.

The part was a paper thin labyrinth seal for a jet engine. There was no way to hold the part with out distorting it,jawed chucks distort work. We only roughed with chucks. Turbines require many thin walled parts held to very small tolerances. We would do what ever it took to get a part round within tenths.

Very light cuts and a negative raked tool did not move the part. I used thin CA glue and soaked the part in debonder to get it off.

I am curious if there are better glues that would work better than CA. Something that you could use heat to release, and dip in a solvent to get rid of the residual glue.
 
For CNC profiling, I've held sheet against a sacrificial aluminum plate using hot-melt glue. It holds fine, but cleanup is a PITA. The best solvent I have found is kerosene, but it turns the glue into slimy goo. I have also held sheet onto MDF board by covering the part with wide strips of blue masking tape on the part and on the MDF, and then sticking the tape layers back-to-back with superglue. The part comes off fairly easily with a knife or chisel, and cleanup is a breeze. With the masking tape trick, it's a race against time before coolant soaks into the MDF and wrecks the bond. Ideally, you set the DOC to just break through the metal, and not the second tape layer, so as to protect the MDF from moisture. However, given MDF thickness tolerances and clamping, it is hard to keep the DOC in the layer you want. You have to be careful to avoid wrinkles or overlaps in the tape layers.
 
Two questions regarding the OP's application:
Will the adhesive have sufficient shear strength to allow a reasonable depth of cut?
Will the heat generated during turning and boring degrade the adhesive?
 
I have personally had OK luck using CA (superglue) to hold an aluminum part to a mandrel. Here are the gotchas:
1. Both parts must be clean to get the glue to set.
2. It takes a fairly long time (8 or 12 hours - I did overnight) for the glue to cure enough to be useful.
3. You need good fitup.
4. Your mandrel/holding plate, etc. needs some kind of holes for acetone or other solvent to get the glue to dissolve it. Otherwise it will take an insane time to get it apart. In my case the entire assembly had to sit in paint can (closed) of acetone over a day or two.
5. It's a bit of a pain to clean the glue residue off.

But yes, it can and does work.

For the described task (part is flat) I wonder OP wouldn't be ahead to make 2 flat sacrificial sheets and sandwich the workpiece between them. Clamps hold the sandwich bits with righteous force, but need not actually clamp the actual workpiece. I would think this would be a job for a face plate.
 
Consider clamping to either a faceplate or a chucked and faced slug or plate.
My experience with using adhesives to hold a part was limited to grinding custom carbide drills on two sided tape- it worked but was not extremely precise-more art than science.
 
I had to face washers to .029 for a friend. I used hot hide glue on a medium density board about 5" in diameter. Installed in a 4 jaw and faced them to dimension. Removed the washers with a heat gun. Hot water and a small brush cleaned the residue. This was the second try, first try was with shellac. Several washers popped off the face plate. I stopped and went to the hide glue which worked well.
mike
 
there are many wax type adhesives. usually a mix of materials to get adhesive strength but some slight flexibility to bond so it doesn't suddenly fail. glass lens makers have been using for over 300 years.
.
i sometimes use double side .015 or .030" thick foam tape. my experience thinner tape sometimes wont flex enough. actually foam tape can hold so well it can take time to get parts apart. sometimes use heat gun or solvent to loosen bond. obviously if using solvent got to watch heat gun igniting the solvent
 








 
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