Wiley Posted June 25, 2015 Share Posted June 25, 2015 I purchased these tubes to use as bottom shot cores for 3" shells: http://pyrocreations.com/inc/sdetail/512/62952 I couldn't help but notice that they are not 2.5" exactly; they're just a hair under, maybe a little less than 1/16" smaller. This of course means that a 2.5" end disk overhangs the tube by that same little bit, which means that the spiking might not touch the walls of the core. Do I need to build these up to exactly 2.5" or will they be fine as-is? Link to comment Share on other sites More sharing options...
Mumbles Posted June 25, 2015 Share Posted June 25, 2015 Have you checked if either your tubes or your disks are slightly out of spec? I've used those tubes quite a bit, and everything always fit for me. Maybe there are variations between batches? Maybe both of my disks and tubes were conveniently out of spec together? Link to comment Share on other sites More sharing options...
Wiley Posted June 25, 2015 Author Share Posted June 25, 2015 I'm still waiting for my box of disks to arrive, but I did measure the tubes with calipers and placed them on a circle made with a compass that was exactly 2.5". The tubes are definitely undersized. Link to comment Share on other sites More sharing options...
nater Posted June 25, 2015 Share Posted June 25, 2015 I would add a few turns of paper to build them up the same size as your discs, or cut smaller discs. It will be easier to spike and paste if the discs are not overhanging the core. Link to comment Share on other sites More sharing options...
mikeee Posted June 26, 2015 Share Posted June 26, 2015 (edited) Spiking under tension is usually enough to cause the string to cut into the end disk unless you have a really thick hard end disk. An extra wrap or two of paper around the bottom shot core prior to spiking would be an easy solution if needed. Some people cut little notches on the end disk after marking the pattern they intend to spike the shell with this would also allow the string to stay in contact with the core. The little cuts/notches keep the string from slipping off when spiking under tension while using some of the offset patterns. Edited June 26, 2015 by mikeee 1 Link to comment Share on other sites More sharing options...
Wiley Posted June 26, 2015 Author Share Posted June 26, 2015 They really don't overhang by much. I'll make a few with a built-up OD and a few without. Also, I feel like my case former needs to be the same diameter as the OD of a finished bottom shot. If it's just a 2.5" former, the breaks that I make with it to stack on top of a case rolled around a bottom shot will look small. I haven't finished a bottom shot yet, but I'm guessing it will be around 2 5/8". Link to comment Share on other sites More sharing options...
mikeee Posted June 26, 2015 Share Posted June 26, 2015 A few wraps of paper around your case former and you have a 2-5/8" diameter tool. Link to comment Share on other sites More sharing options...
Wiley Posted June 26, 2015 Author Share Posted June 26, 2015 Right. That's actually how I make my case formers. I started with a 2" dowel on this one and built it up with ramboard and posterboard. Link to comment Share on other sites More sharing options...
WonderBoy Posted June 27, 2015 Share Posted June 27, 2015 I haven't ever used those tubes, but unless there is a significant difference I wouldn't worry too much about it. But as others have said, rolling on a bit of paper would be a quick fix if it causes problems. I routinely use 4" cores that are slightly undersized for my disks. The biggest issue I have had is when I'm rolling a long casing over the BS, if the disks are not perfectly centered, the casing you roll may be a touch wonky and give you problems when putting in inserts. WB Link to comment Share on other sites More sharing options...
Wiley Posted June 28, 2015 Author Share Posted June 28, 2015 Mikeee, you were correct about the spiking biting into the disks. I made some disks from 1/8" chipboard that were exactly 2.5" OD. I doubled these up and used the double-thick disks on top and bottom of the core. The two strands of 20# hemp really dug into the disks well and came very, very close to touching the walls of the core; I had to hold them up to a light to see that there was a tiny gap. No big deal there. They measure just a hair under 2 5/8" when spiked and pasted, so my former is now about that size. I've already made a two break-and-report and everything fits beautifully. These larger shells are so much less of a pain to build than their consumer-sized counterparts. Link to comment Share on other sites More sharing options...
Mumbles Posted June 29, 2015 Share Posted June 29, 2015 Using an allpax cutter or other gasket cutter would allow you to custom fit the disks to the cores. They also come in handy for larger shells where the disk cost starts to add up. Alternatively, I have run into this problem before when I was building with a friend, and forgot my normal former at home. We had to find an OTC replacement. We ended up finding a tube that was slightly undersized, and the disks wouldn't lay down inside the rolled casing. If you take the disk, set it up on it's end on the table, and lightly tap the edges, it will feather out a bit and decrease the diameter. You can probably comfortably reduce the diameter by as much as 1/8" without much of a problem. I'm not sure how well this would work for a hardwalled case like this though. In retrospect, we probably should have just increased the former. Link to comment Share on other sites More sharing options...
Wiley Posted June 30, 2015 Author Share Posted June 30, 2015 That's the other thing, the Wolter disks are slightly undersized too. They fit the cores perfectly. Link to comment Share on other sites More sharing options...
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