When to Align Bore a Type IV case |
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When to Align Bore a Type IV case |
Kansas 914 |
Oct 18 2010, 08:22 AM
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#1
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Advanced Member Group: Members Posts: 2,999 Joined: 1-March 03 From: Durango, Colorado Member No.: 373 Region Association: Rocky Mountains |
When does one decide a case has to be align bored? I have a GC case that I am getting ready to take to the shop to check for register collapse but have no idea what the criteria might be to consider align boring.
Thanks in advance! |
HAM Inc |
Oct 18 2010, 01:29 PM
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#2
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Senior Member Group: Members Posts: 846 Joined: 24-July 06 From: Watkinsville,GA Member No.: 6,499 Region Association: None |
QUOTE Its fixing the collapse that is a little harder. But I bet anyone with a mill would be able to do it. Getting the spigots machined properly requires that the mill head is trammelled (squared) to the mill table extremely accurately. One of my mills is dedicated to head flycutting and case decking. I keep the head trammelled to .0003"- .0005" over 32". That works out to .0000375"- .0000625" over 4.0". I also have a heavy steel fixture that stays mounted to the mill table that is decked to the specific trammell. I torque the case halfs to this fixture (and clamp heads to it for flycutting) through the 6 main case bolt bores to simulate actual assembly. Aside from not having the fixture most shop with a mill don't go to the trouble to trammell to such exacting specification. A typical shop will trammell to .0005-.001" over 4-6". That is not accurate enough for spigots. Ask a lot of question of the shop you consider for this proceedure. It is not forgiving! |
Kansas 914 |
Oct 18 2010, 02:04 PM
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#3
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Advanced Member Group: Members Posts: 2,999 Joined: 1-March 03 From: Durango, Colorado Member No.: 373 Region Association: Rocky Mountains |
QUOTE Its fixing the collapse that is a little harder. But I bet anyone with a mill would be able to do it. Getting the spigots machined properly requires that the mill head is trammelled (squared) to the mill table extremely accurately. One of my mills is dedicated to head flycutting and case decking. I keep the head trammelled to .0003"- .0005" over 32". That works out to .0000375"- .0000625" over 4.0". I also have a heavy steel fixture that stays mounted to the mill table that is decked to the specific trammell. I torque the case halfs to this fixture (and clamp heads to it for flycutting) through the 6 main case bolt bores to simulate actual assembly. Aside from not having the fixture most shop with a mill don't go to the trouble to trammell to such exacting specification. A typical shop will trammell to .0005-.001" over 4-6". That is not accurate enough for spigots. Ask a lot of question of the shop you consider for this proceedure. It is not forgiving! Len, Thanks for the great information. There is only one place to go for quality work like yours and that is your shop! I hope those that want it done right know that. Unfortunately this is a budget build for the neighborhood kids (and some of the Dad's) to learn from and I am the bank... But I am a lot better informed to talk to the shops here in town. |
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