Removed a bevel base

Ian

Notorious member
I wanted to share a photo of my first mould modification with a lathe. This was done with a 3", 4-jaw chuck from LMS, the Grizzly G0765 7x14 mini lathe, and a boring bar I ground from a piece of 3/16" square HSS that 'Perfesser' Keith B. was kind enough to donate to the cause of my general learnin'.

This mould is from 2009, right smack in the worst era of Lyman undersizedness and outofroundedness, so in order to use it at all I had previously fixed both problems via lapping but never was too thrilled with the bevel base when it came to lubing. I have a second, older mould that is near perfect, so this one got the nod for modification. Bottom right is a bullet I cast maybe 6-8 years ago showing the bevel base.


452664 flat base.jpg
 
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Ian

Notorious member
It's as near as I could get it, better than my photography skills anyway! I sharpened the corner where the base band and lube groove shank meet, it was a bit radiused from the severe lapping job I once gave it (about .0045"), and the shiny ring seems pretty concentric to the minor of the lube groove. Chinesium test indicator is pretty much junk so it was a little bit of a struggle to indicate below two tenths. The diameter difference between the two is less than my measuring ability with a ball gauge.

452664 flat base2.jpg

That's Beagle's fine old mould in the fuzzy background.
 

Gary

SE Kansas
Very nice Ian, very nice. I hope to do some stuff like you're doing in the near future, baring any more gear troubles.
 

Ian

Notorious member
Thanks, Gary. You won't break any gears shaving off a tiny bit of leaded steel with a 3/16" square boring bar.
 

Brad

Benevolent Overlord and site owner
Staff member
My feeling to a certain extant is that that type of modification need not be perfect. Make the base a bit larger if required, the sizer will take care of it.

Well done Ian. Indicating those moulds isn't easy the first time or two.

Now use your boring tool to make the bands larger. That will make your hair gray, trust me.

I will mess with my moulds. I will mess with Paul's moulds. I ain't touching anyone else's moulds.
 

Ian

Notorious member
Now use your boring tool to make the bands larger. That will make your hair gray, trust me.

It wouldn't be too bad except having to get the whole mould true in the jaws. With this tiny 4-jaw chuck I was really past the advisable extension limit of one jaw, so the mould tended to kick out from the chuck face 2-3 thousandths when snugged down. That's no problem for the base band, but while it was running concentric, there was some very slight wobble on the longitudinal axis. I used a dead-blow mallet a few times to get the mould back against the chuck face but every time I adjusted the jaws even a little it pulled away again.

This little machine makes it easy to feel around down inside a bullet mould cavity with a boring bar due to low mass of the carriage. As an experiment I tracked the nose band and middle band with the spindle at rest just to see how that would work and it's not too bad. With an indicator on the carriage marked for the critical depth limits and feeling the touch-off point with the cross slide I felt reasonably confident in being able to enlarge nose and middle bands, the only issue for me is getting the wobble out beforehand.
 

KeithB

Resident Half Fast Machinist
Of course one problem with REboring a mold is getting everything lined up with the original boring. Did the OEM line things up using the sides of the mold, or the bottom or top? Of course you have to line things up with the funny shaped hole in the center, which may not line up with ANY of the mold faces. If it's a traditional Lyman mold it was cherry cut in a double acting vise, and you have to try and redo it using a lathe and a 4 jaw. Fun stuff!

How long did it take to do this? How long would it take you to do another one? How much would you have to charge to just break even? I hope people reading this get some understanding of why folks like Buckshot and other commercial mold-modders have to charge what they do for this type of work.
 

Ian

Notorious member
I have a blank face plate (well, it has t-bolt slots in it), but haven't purchased a clamp kit for it yet. I suppose it wouldn't be too tough to make a couple of straight clamping bars for moulds. When I realized the 4-jaw was going to be at its limit even with this small block set I almost got the plate out, but wasn't sure how I would adjust the mould on the face to indicate center. Thinking about this now I realize that's what lead hammers are for....:rolleyes:

First I had to re-set the alignment pins and get the mould tight or this was all going to be a waste of time, so that was ten minutes right there. It took me about 15 minutes to get the first cavity indicated, about 5-8 to get the second one indicated, and about 5 minutes a piece to bore and check the bases. That's not counting the half hour changing chucks, chomping gum and cogitating on the setup, or the 15-20 minutes selecting and grinding a tool and 5 minutes or so shimming the tool to center in the lantern tool post. I spent about an hour and a half in the garage to get it all done and cleaned up. I might get it done in 45 minutes next time if I had a better setup on the headstock, better test indicator, and the tool already made.

The forward cavity was originally bored off-center in the blocks, meaning deeper in the RH block (opposite sprue plate). There was also some shift in the blocks due to Lyman's sloppy boring vise and torque of the spinning cherry, so both cavities were out of round. That had been taken care of by the lapping. If that had still existed I would have to have ground a tool to the exact profile of the cavity and shaved the whole thing after indicating dead center based on the parting line. The shaping tool would need to cut on the back side and spindle run in reverse to not grab and break on the sharp edges of the cavities. I did ponder the value of this kind of work, to me, because I'm thinking of offering the service after I get more confidence in what I'm doing. Right now it wouldn't be worth my time to do this for less than $25 per cavity in the shop, and when you consider the amount of time the administrative and logistic end of things soak up I'd really need a good bit more than that to do it on a mail order basis and expect to "profit" from it in any way.
 

Brad

Benevolent Overlord and site owner
Staff member
Buckshot worked cheap. I don't know how he made money doing what he did for what he charged.
Time is the big cost. Even if it took just 20 minutes to do a mould like that figure in another 5 minutes to get the mould ready for shipping. What about the potential loss if a mould is damaged? Then factor in the hassle of people hounding you to get it done yesterday despite having a real job and family not to mention hoping to actually have a life too.

There is a reason I vowed to keep my lathe a hobby and not a business.

Keith, I can see the benefits of a CNC set up like yours.
 

KeithB

Resident Half Fast Machinist
Hand time is expensive time. I can appreciate hand built and hand fitted products but very few of us could afford most manufactured goods (and I'll put farming in that category) if all the work was done by hand. Messin' with your own or a buddy's mold is fun, but don't quit your day job!
 

Pistolero

Well-Known Member
Very nice. but "indicating dead center, based on the parting line". I understand the
concept of dead center on the parting line, but can imagine no way to indicate to it with
the two mold halves gripped together in a 4 jaw chuck. What am I missing?

Did you turn the jaws around backwards for this? Seems like that would grip better, if they will
go small enough that way. May not.

Keith, your #11 post is right on. Doing something for fun in your spare time for yourself, is
WAY different than trying to do it for money. I am a pretty good home auto mechanic, can
and have fixed about anything over the decades, but I do realize that I would starve as a
pro mechanic, too slow, too fussy. Pretty similar (although nowhere near as experienced) in gunsmithing,
I can do some neat stuff for me, but would starve as a gunsmith, too.

Bill
 
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smokeywolf

Well-Known Member
People who commission machining projects are oblivious to the expenses involved. A short list would look something like:
  • Labor
  • Utilities
  • Wear and depreciation on machinery
  • Expendables
    • cutters
    • cutting fluids
    • Abrasives
    • Layout fluids, bluing solutions, parts cleaning solutions, polishes, lapping compounds, etc.
    • Pencils, pens, markers, stationery
    • Maintenance supplies for shop and machinery
      • cleaners
      • rags
      • oils and greases
      • spill control
        • kitty litter
        • saw dust
        • Absorb
      • light bulbs
    • Packaging
  • Project specific tooling
If you're operating an enterprise for profit, add things like insurance, permitting and taxes and don't forget, profit (maybe).
 

KeithB

Resident Half Fast Machinist
Good list, there are a whole lot of bills to be paid when you run a biz. In a few months we'll have a construction loan to pay along with everything else. Luckily between me and Scott we can do most things ourselves as far as repair, maintenance, etc.
 

smokeywolf

Well-Known Member
Never owned a machine shop that had to turn a profit, but ran a machine shop for several years and have some familiarity with costs and I did have to bid jobs against outside machine shops.
Used to have a sign in my office with the words, "A Good Job is Never Cheap" engraved on Gravoply with the Gorton pantograph and just below that, the words, "And a Cheap Job is Never Good" scratched into it by hand.
 

Ian

Notorious member
Very nice. but "indicating dead center, based on the parting line". I understand the
concept of dead center on the parting line, but can imagine no way to indicate to it with
the two mold halves gripped together in a 4 jaw chuck. What am I missing?

Did you turn the jaws around backwards for this? Seems like that would grip better, if they will
go small enough that way. May not.

I used the "outside" jaws (long ends) so I could bottom the mould blocks out on the chuck face. It's kind of difficult to explain how I indicated the center of the parting line, but I'll try...it was kind of like setting tool height to center but involved tramming the mould seam level with the cross slide. First I ground a sharp point on a piece of baling wire and clamped it in the tool head so it pointed at the parting line with the line horizontal. Then I used the cross slide to tram the wire across the mould top from front to back and nudged the spindle until it trammed level. Then I moved the carriage just a bit to pull the wire out of the way and rotated the spindle 180° and repeated the process of leveling the seam. The wire was of course tracing off from the plane of the seam, so I moved the mould in the jaws to split the difference with the previous setting, indexed the spindle again, then bent the wire a little to be on the line, and repeated the whole process again until the wire point would trace the mould seam exactly with the spindle in either orientation. I used a machinist's microscope and pen light to view the wire tip to seam relationship, very tedious but effective. Turns out to be a waste of time when removing a bevel base on a mould with existing cavities....particularly if the cavities are bored off-center to begin with. In the final analysis I indicated the blocks with a test indicator running in the rear driving band groove to keep the new cuts concentric with the old. On the other mould which I re-bored entirely, or if I were to start with a blank block set, the scribe trick works. Sure would have been easier with a height-adjustable tool holder!
 

Pistolero

Well-Known Member
Well, that is pretty darned cool, Ian. Would have not thought that you could trace that
seam. Of course if not, then open the blocks and break the edges just a touch with a
stone and then you have a good seam to work with. I kept wondering how you would
have any access to the surface to reference with a dial indicator.

Great job.

Definitely understand that all the stuff in my shop which is paid for already,
and is just "free" for my projects is NOT free in a for-profit shop. And my labor
is free, too.:p:confused: Sometimes it is pretty skilled labor, other times....not so
much.:eek: Always fun.

Bill
 
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