deburring moulds?

[Newtire]

I had an idea that might work so thought I'd ask & see if anyone else has tried this. It's one of those moulds that resists the Kroil treatment (last thing I tried) and cleaning with a pencil eraser.

Is there anyone ever tred polishing the mould in their vibrating case polisher with the mold halves clamped shut and the sprueplate removed? Nothing else in the polisher of course. Seems like this might just shine out the rough spots maybe?

[TAWILDCATT]

you have not read the sticky on that subject.

[462]

What about doing one block at a time?

[Newtire]

you have not read the sticky on that subject.

I thought beagling was just opening up the mould a bit with the high temp metal tape. I tried searching for it but couldn't find the original thread. Anyway, I think I might try doing one side at a time as suggested-why not!?

[mold maker]

I thought beagling was just opening up the mould a bit with the high temp metal tape. I tried searching for it but couldn't find the original thread. Anyway, I think I might try doing one side at a time as suggested-why not!?

That might allow the edges of the cavities to be rounded, causing a much more pronounced parting line, or even a knife edge.
While your method sounds interesting, I'd go verrrrry slow and really check often. You'll probably find that walnut or any other media will be trapped between lube grooves, limiting the desired effect.
Those of us that have tried the bullet, and compound, comet, or tooth paste, to open up and polish the cavities, have mostly had great success. Even that method is a, "do a little and look a lot", chore. There is just no easy, or free ride way, except spending cash and buying somebody else's labor.

[HORNET]

Read the "Leementing" stickies. Beagling is for undersized, not burrs. I dion't think the polisher's going to work. If you do the halves separately there's a good chance of rounding corners that you want to be sharp and it still might not remove the burrs that are ausing the problem. If you do the blocks assembled, I don't think the media will have enough access and mobility to do much deburring.

[Newtire]

I went ahead with the polisher and no rounded corners (iron mould) and about the only thing it did show up is some scratching in the boolit nose area that wasn't visible before all the crud was cleared out. Casts alot better now. No seams or out of round. Would have to be some pretty gnarly stuff to eat away at a cast iron mould I'd think. Anyhow, polished up the nose area with some fine steel wool and now is casting much much better.

[geargnasher]

Ok, here's an idea: lightly coat the inside of the mould with Pam or light oil, mix some fresh treated corncob media with some sort of glue (Elmer's?) and pack it into the cavities with a dowell rod or something to make an abrasive cob "boolit" with a shaft. Wait for the glue to dry, open the blocks to clean out any glue residue and "lap" the mould by spinning the boolit in the cavity with the blocks closed.

Gear

[theperfessor]

geargnasher

I think you've got something there. I've thought about how to make conformal polishers. I know many people use lead alloy boolits coated with lapping compound to polish/enlarge cavities. I was thinking of trying an epoxy type material used to anchor bolts in concrete. It is supposed to have a positive expansion rate as it sets up, expanding instead of contracting as most glues do. Add some abrasive powder to mix as you combine both parts of epoxy. Coat the mold inside with light oil as you suggest, and then fill the cavity with epoxy and add a drive shaft. For less enlarging/more polishing use your corncob (or fine walnut hull) media instead of abrasive.

Darn, now I've got another project idea to think about...

[geargnasher]

Perfessor, I wonder if Hugh Akston packed a .38 snubby? I'll bet he did!

Gear

[Bret4207]

If burrs are the issue then why not deburr it? All it takes is a small tool a set of reading glasses or magnifier and some time.

[theperfessor]

Who is Hugh Akston? I'm clueless on this one.

[Bret4207]

Character from Atlas Shrugged.

[theperfessor]

Oh, OK, I read that a looooong time ago. All I remember of the characters is John Galt and Dagney somethingorother. That book is one reason I went into engineering. I like Rand's philosophy but she led a fairly unhappy life in her later years.

Back to main topic now...

[Gunfixer]

Gear... interesting idea
Perfessor... I have used a lot of the concrete anchoring epoxies in the past, you are correct in that they expand. In the ones I have used they skin over on exposed surface relatively smooth but are very coarse due to bubbles(making them expand) once the surface is broken. They were hell on bits trying to fix improperly placed rebar and plate anchors
Might work but slow experimentation on an already ^%$*%$( mould would be in order

[geargnasher]

Character from Atlas Shrugged.


I'm impressed. That trivial reference may have been a stretch even for Perfessor with the Rand quote.

Gear

BTW, I tried making a cob lap with hot glue, works pretty well if you warm the mould first and poke it down in there firmly, use as little glue as possible and use a small dowel rod shaved flat on the end or something similar for a shaft, otherwise it will break loose and spin inside the cob

[Bret4207]

I'm impressed. That trivial reference may have been a stretch even for Perfessor with the Rand quote.

Gear


Don't be too impressed. My copy of "Atlas Shrugged" is the $5.99 version with the tiny, tiny print. It lies unread, waiting for the winter ahead.

Google solved the identity for me.

[Dragoon]

It's very easy to drill a small hole in the base of a bullet and install a wood screw to turn it with. Put a little 320 grit lapping compound on the bullet and turn by hand. When the bullet will turn freely with the mould blocks tightly together, the mould is nicely polished and deburred.

[TAWILDCATT]

I take a stone across the face of all lee molds.then break the corners of mold with fine file.works for me.:coffee:

[StarMetal]

I like Bret's method...esp that magnifying glass. That way you don't ruin the seam of the mould.

Joe

[lurch]

It's very easy to drill a small hole in the base of a bullet and install a wood screw to turn it with. Put a little 320 grit lapping compound on the bullet and turn by hand. When the bullet will turn freely with the mould blocks tightly together, the mould is nicely polished and deburred.

Having just been this route to increase the nose on a bore rider, I found it easier (at least on my nerves while dinking with the mold) to:

1. Make a jig for the boolit by drilling (drill press) a hole in a piece of hard 1x2 wood a couple inches long (or whatever scrap you have around that looks like it might work...), then slit the wood almost it's complete length with the grain on a band saw.

2. Put the wood in a drill press vise and slip a boolilt in the hole and tighten the vise enough to hold the boolit but not deform it.

3. Drill a slightly over recommended tap drill size hole in the center of the boolit about 1/2" or so deep (used 6-32 for this go around).

4. Run a tap in until it bottoms using a T handle.

5. Put the boolit back int the mold with a little light machine oil and rotate it a few times without grit to start with. Clean out any lead shavings that result - thouroughly. You'll also figure out real quick if your mold is casting round boolits or not.

6. Put some grit on the boolit - I used 400 as that's what I had - and give it a few turns. Don't over do it or you'll end up increasing the size of the boolit some - or maybe you want to do that...

7. Clean things up and try a few more casts and see where things are - repeat as necessary.

I saw the idea for the tap & T handle somewhere on the net but don't have a lathe as was in that article. This seemed to work pretty well and let me get a decent handle with some feel to it for turning the boolit "lap". Using an oversize tap drill makes the tap a lot easier to get out of the boolit when finished, but still has enough bite to turn the boolit in the mold if you take it easy to start with and don't grip the boolit with the mold too hard.

Worked for me, YMMV....

[sleeper1428]

Having just been this route to increase the nose on a bore rider, I found it easier (at least on my nerves while dinking with the mold) to:

1. Make a jig for the boolit by drilling (drill press) a hole in a piece of hard 1x2 wood a couple inches long (or whatever scrap you have around that looks like it might work...), then slit the wood almost it's complete length with the grain on a band saw.

2. Put the wood in a drill press vise and slip a boolilt in the hole and tighten the vise enough to hold the boolit but not deform it.

3. Drill a slightly over recommended tap drill size hole in the center of the boolit about 1/2" or so deep (used 6-32 for this go around).

4. Run a tap in until it bottoms using a T handle.

5. Put the boolit back int the mold with a little light machine oil and rotate it a few times without grit to start with. Clean out any lead shavings that result - thouroughly. You'll also figure out real quick if your mold is casting round boolits or not.

6. Put some grit on the boolit - I used 400 as that's what I had - and give it a few turns. Don't over do it or you'll end up increasing the size of the boolit some - or maybe you want to do that...

7. Clean things up and try a few more casts and see where things are - repeat as necessary.

I saw the idea for the tap & T handle somewhere on the net but don't have a lathe as was in that article. This seemed to work pretty well and let me get a decent handle with some feel to it for turning the boolit "lap". Using an oversize tap drill makes the tap a lot easier to get out of the boolit when finished, but still has enough bite to turn the boolit in the mold if you take it easy to start with and don't grip the boolit with the mold too hard.

Worked for me, YMMV....

The wooden jig that you describe is precisely the technique that I use to hold any boolit that I can't easily chuck in the lathe. Most handgun boolits fall into this group so I have a series of these jigs made up for the different calibers that I cast. It just never crossed my mind to describe these small, easily produced jigs since I've made a lot of jigs for different purposes over the past few years and I guess I just assumed that others would have already thought of this simple, straight forward method of holding a boolit while you drill the base. I'm sure this will help a lot of people who are having a hard time figuring out how to hold a boolit securely without deforming it while a hole is drilled in the base. Good going!!

sleeper1428

[HORNET]

lurch missed a couple of minor details. Hold the mold blocks in a vice while you're lapping. If there's any out-of-round that you missed, you're NOT going to hold those blocks closed against the 'camming' forces. Start slightly loose and tighten. Stop often to clean the faces of the blocks.

[dogbert41]

I used Brasso with Qtips on the last 6 mold. Will know sometime this week how they drop, but close inspection, they look polished really smooth and shiny.