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Weighing bullets - process control (Read 47243 times)

Cat_Whisperer Frequent Elocutionist Offline No 1, 9.3x74R Posts: 3878 Location: Mountains of Virginia Joined: Apr 17^th, 2004	Re: Weighing bullets - process control Reply #75 - Nov 28^th, 2013 at 9:45am	Print Post
	gunlaker wrote on Nov 27^th, 2013 at 11:03pm: What 40_Rod says makes sense with respect to heat. I think that the bullet will shrink just a little as it cools. I found a couple of years ago that when bullets stick I can usually get them to drop nicely by simply waiting longer before opening the blocks. ... Chris. Agree. It happened at the same time of changing processes, confusing the issues. Apparently the lead shrinks at a faster rate than the iron. Often I'll use a 1" fan to cool the filled mould to accelerate the process. In addition, (it appears to me) that the best grip the bullet has on the mould is right at the edge of the cavity. So I use a lube (tungsten dioxide) on the mould surface. A little will undoubtedly sneak around the edge - but it only lasts for a few hundred cycles. This may have pooched out at this time as well. It took me by surprise to go instantly from a super-smooth process of bullets falling out by looking at them to having to beat them out. Well - time to clean off the casting area and build in the PID controller and move the computer in closer.

	Cat Whisperer (trk) Chief of Smoke Pulaski Coehorn Works and Skunk Works Drafted May 1970, Retired Maj. U.S.Army assra #9885
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Cat_Whisperer Frequent Elocutionist Offline No 1, 9.3x74R Posts: 3878 Location: Mountains of Virginia Joined: Apr 17^th, 2004	Re: Weighing bullets - process control Reply #76 - Nov 28^th, 2013 at 9:46am	Print Post
	JLouis, JoeW - Good suggestions!

	Cat Whisperer (trk) Chief of Smoke Pulaski Coehorn Works and Skunk Works Drafted May 1970, Retired Maj. U.S.Army assra #9885
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CanoeRoller Ex Member	Re: Weighing bullets - process control Reply #77 - Nov 28^th, 2013 at 9:09pm	Print Post
	JLouis wrote on Nov 23^rd, 2013 at 10:34pm: I find your 10 grain variance by changing your hold closed pressure on your handles interesting. How much further past closed can one close their mould blocks? That subject in itself has always interested me as it I have found it to be impossible based on my experience. I can't help but think of it as how much open from fully closed would create a 10 grain variance while still not having lead flowing in between the mould halves? JLouis The heaviest rounds did have obvious finning, though I could see a distinct seam that had formed. My conclusion was that a loose hold, could lead to bullets that were heavier and slightly out of round.


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CanoeRoller Ex Member	Re: Weighing bullets - process control Reply #78 - Nov 28^th, 2013 at 9:11pm	Print Post
	or rather did not have obvious finning. This image was the final round, and I held the moulds so loosely, that the lead was leaking out of the mould as I poured, so I only got part of the mold to fill.


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frnkeore Frequent Elocutionist Offline Posts: 7281 Location: Central Point, OR 97502 Joined: Jun 16^th, 2010	Re: Weighing bullets - process control Reply #79 - Nov 28^th, 2013 at 9:15pm	Print Post
	Quote: JLouis wrote on Nov 23^rd, 2013 at 10:34pm: I find your 10 grain variance by changing your hold closed pressure on your handles interesting. How much further past closed can one close their mould blocks? That subject in itself has always interested me as it I have found it to be impossible based on my experience. I can't help but think of it as how much open from fully closed would create a 10 grain variance while still not having lead flowing in between the mould halves? JLouis The heaviest rounds did have obvious finning, though I could see a distinct seam that had formed. My conclusion was that a loose hold, could lead to bullets that were heavier and slightly out of round. Be sure that the mold handles AREN'T touching the mold block. They should touch only the pin/screw, nothing in front or to the rear. If you use DC handles on a SC mold (or visaversa) the blocks won't close all the way. The the sprue plate to the side, hold the block up to a light and you should not see any through the bolcks. Frank

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Cat_Whisperer Frequent Elocutionist Offline No 1, 9.3x74R Posts: 3878 Location: Mountains of Virginia Joined: Apr 17^th, 2004	Re: Weighing bullets - process control Reply #80 - Nov 30^th, 2013 at 10:59pm	Print Post
	Spent the days off cleaning off the casting area. Moved the computer in on the same bench. Started with a new 20+ lb batch of alloy. Started with a new-to-me one cavity Lyman 35863 mould. Prepped the sprue cutter by taking it off and lubing it and the top of the mould, adjusted it. Cast 100+ After the 40 I picked that row to start weighing as it looked like the process was going smoothly. I am LEARNING to drop just the right amount of alloy and stop the flow (most of the time) so that the puddle is the same on the top of the sprue cutter. The first one I weighed (after casting) looks just like the others - must be an internal void. I wish I had a method of recording exactly which ones had good uniform puddles on top and which ones ran over. Sprues were dumped in a bread pan, added after the 100+ were done. Bullet is a beveled ends double ended 3 groove wad cutter. 3 or so were pitched during casting because it didn't look filled out quite to the edge when the sprue was cut. I think I agree totally now with 40 rod on dropping from the mould is temperature issue. I did NOTHING for mould-face prep. First 10 or so I pitched. Did so until the rhythm got to where I would cast, set mould down and move previous bullet to cooling tray, hit the mould (hinge of handles) ONCE to drop the bullet on toweling. I can see this is going to be a SEASON (winter) of learning the disciplines of pace and timing in casting.

	Cat Whisperer (trk) Chief of Smoke Pulaski Coehorn Works and Skunk Works Drafted May 1970, Retired Maj. U.S.Army assra #9885
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Schuetzenmiester Frequent Elocutionist Offline Posts: 6707 Location: Cool Wet Side of WA Joined: Apr 27^th, 2008	Re: Weighing bullets - process control Reply #81 - Dec 1^st, 2013 at 12:16am	Print Post
	I spent years weighing bullets and trying to figure it out. A thermocouple on your mold will tell the tale. It is mold temp at the time of the pour that is critical assuming you have reasonable technique and a constant lead temp of about 775 +/-. I usually throw the first bullet back or save for fouler, but they will all be +/- .5 gr or less casting 525 gr .45s. Usually, +/- .1 or .2 gr for hundreds of 215 gr .33s.

	"some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence
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Cat_Whisperer Frequent Elocutionist Offline No 1, 9.3x74R Posts: 3878 Location: Mountains of Virginia Joined: Apr 17^th, 2004	Re: Weighing bullets - process control Reply #82 - Dec 1^st, 2013 at 12:24am	Print Post
	That's the next step - the reason for the computer - to track temp of alloy, mould and time.

	Cat Whisperer (trk) Chief of Smoke Pulaski Coehorn Works and Skunk Works Drafted May 1970, Retired Maj. U.S.Army assra #9885
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GlennM Newbie Offline Posts: 9 Joined: Aug 13^th, 2013	Re: Weighing bullets - process control Reply #83 - Dec 1^st, 2013 at 3:17am	Print Post
	I also had another casting session today since the temperatures rose back up to more normal (mid-60's). Now... to throw another caveat into figuring out bullet casting: A week ago I cast 140 pcs. 420 grain 40-65 bullets with 20/1 certified alloy. All weighed and sorted by weight. Today cast another 118 bullets... same mould (Paul Jones postel), same casting temps... same alloy... very close outside temps... same rhythm... etc. Wouldn't ya know it: the batch processed today averaged approximately .4 grains heavier than last weeks bullets. It can't be me... gonna have to find something else to blame... perhaps the electronic scale, or the dog.....


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MikeT Senior Forum Member Offline Posts: 294 Location: St. Cloud, MN Joined: Sep 7^th, 2005	Re: Weighing bullets - process control Reply #84 - Dec 1^st, 2013 at 8:42am	Print Post
	Glenn, How about relative humidity and barometric pressure? Keep on hav'n fun! MikeT


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Schuetzenmiester Frequent Elocutionist Offline Posts: 6707 Location: Cool Wet Side of WA Joined: Apr 27^th, 2008	Re: Weighing bullets - process control Reply #85 - Dec 1^st, 2013 at 8:45pm	Print Post
	Sounds like mold temp to me. Rhythm doesn't cut it. Pouring the bullet at the same mold temp +/- 5 degrees is what I found to give the best results. +/- 10 degrees still makes good bullets, but the weight starts to vary.

	"some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence
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JLouis Frequent Elocutionist Offline Posts: 10625 Joined: Apr 8^th, 2009	Re: Weighing bullets - process control Reply #86 - Dec 1^st, 2013 at 9:48pm	Print Post
	Don't think you will ever see that 4 tenths increase in that batch and wouldn't fret about. JLouis

	" It Is Better To Now Have Been A Has Been Than A Never Was Or A Wanna Be "
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Cat_Whisperer Frequent Elocutionist Offline No 1, 9.3x74R Posts: 3878 Location: Mountains of Virginia Joined: Apr 17^th, 2004	Re: Weighing bullets - process control Reply #87 - Dec 2^nd, 2013 at 9:41pm	Print Post
	So with the 0.4grain difference - could have been caused by the change in temperature of either or both the alloy or the mould. One affecting the density of the alloy the other affecting the volume of the cavity.

	Cat Whisperer (trk) Chief of Smoke Pulaski Coehorn Works and Skunk Works Drafted May 1970, Retired Maj. U.S.Army assra #9885
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Cat_Whisperer Frequent Elocutionist Offline No 1, 9.3x74R Posts: 3878 Location: Mountains of Virginia Joined: Apr 17^th, 2004	Re: Weighing bullets - process control Reply #88 - Dec 2^nd, 2013 at 9:45pm	Print Post
	Until the rest of my instrumentation comes in, I thought I'd cast a few more and compare the differences in weight due to a difference in distance between the mould and the nozzle. 1/2" 3/4" and 1" approximately. Even thought the spread was a little more than the 3/4", if one disregards drift (due to alloy heating/cooling) the 1/2" drop looks to me to have less radical variation. (Sample of 15 each is too small to draw conclusions, but points in that direction.)

	Cat Whisperer (trk) Chief of Smoke Pulaski Coehorn Works and Skunk Works Drafted May 1970, Retired Maj. U.S.Army assra #9885
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shovel80 Oldtimer Offline Posts: 896 Location: Sonora,CA Joined: Jun 6^th, 2011	Re: Weighing bullets - process control Reply #89 - Dec 2^nd, 2013 at 10:39pm	Print Post
	Just my opinion, but I think Your WAY Overthinking casting.... Getting good bullets isn't that difficult, you just have to work a system that works for you and be consistent at it... Terry

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