Installing a new inner C

Hokie_YJ

Hokie_YJ

Well-Known Member
Joined
Jul 22, 2006
Location
Johnson City, TN
Some of you may remember a few months back in my LJ build thread I found a trashed inner C on the SD 60 I’m going to build for it. Well I got that one cut off, have a good used C ready to go on, and have the axle jigged in place on the table. My plan has been to use a weed burner torch to heat the C to get it on the tube and set in place. There’s currently .015” interference fit between the tube and the C. I’m pretty sure I can’t get it hot enough to make it open up that much and the C still be useable. And even if I could I think it would shrink so fast it would be almost impossible to get it right without it getting stuck.

So how much interference should I shoot for, if any? A friend has a lathe we might be able to get the C chucked up in, and I’ve also thought about going at it with a cylinder hone and seeing what I can do. Paging @Tom@Hilltop_Machine and any other of you smart machinist or engineer types.

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Hokie_YJ said:
Some of you may remember a few months back in my LJ build thread I found a trashed inner C on the SD 60 I’m going to build for it. Well I got that one cut off, have a good used C ready to go on, and have the axle jigged in place on the table. My plan has been to use a weed burner torch to heat the C to get it on the tube and set in place. There’s currently .015” interference fit between the tube and the C. I’m pretty sure I can’t get it hot enough to make it open up that much and the C still be useable. And even if I could I think it would shrink so fast it would be almost impossible to get it right without it getting stuck.

So how much interference should I shoot for, if any? A friend has a lathe we might be able to get the C chucked up in, and I’ve also thought about going at it with a cylinder hone and seeing what I can do. Paging @Tom@Hilltop_Machine and any other of you smart machinist or engineer types.

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I'm no engineer. But I've flap wheeled plenty of axle tube until the C went on by hand. Set caster and burn it in.
I'm not saying it's best technique or anything. But it'll hold a redneck with a heavy right foot just fine.
 
Jody Treadway said:
I'm no engineer. But I've flap wheeled plenty of axle tube until the C went on by hand. Set caster and burn it in.
I'm not saying it's best technique or anything. But it'll hold a redneck with a heavy right foot just fine.
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I just ordered a cylinder hone from the storeroom at work, I'm going to see what that might do for it. I'm also looking for some bigger, 4" or so, flap wheels I can put on my die grinder. All I have right now is some 2" ones.
 
15 thousands is a lot. I would half that to 5-7 thousands. You could probably get it real close to going on with heating it with the weed torch and drive it on with a BFH. A good chamfer would help too on the tube so it will want to go on straight.
 
Tom@Hilltop_Machine said:
15 thousands is a lot. I would half that to 5-7 thousands. You could probably get it real close to going on with heating it with the weed torch and drive it on with a BFH. A good chamfer would help too on the tube so it will want to go on straight.
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I'm not a smart man, but I feel pretty confident trying it at 15 is just asking for a disaster. I figured 5 might be doable.
 
Tom@Hilltop_Machine said:
15 thousands is a lot. I would half that to 5-7 thousands. You could probably get it real close to going on with heating it with the weed torch and drive it on with a BFH. A good chamfer would help too on the tube so it will want to go on straight.
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You think a cylinder hone would do anything for it, or just be a waste of time?
 
Tom@Hilltop_Machine said:
Or even bore it out on a milling machine if you have access to one.
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He has a mill, but not really a good way to bore on it. I guess on the lathe you'd just chuck it on the ID and go halfway then flip it around?
 
If I was a smart man that's what I'd do, but I'm stupid and stubborn. :laughing: I've got $450 and 6-8 hrs of work into this damn thing and I'm determined that it isn't going to beat me.
 
heat it to get it on. if it cools before you get it in position, heat it again, will just take a little longer. you really need a rosebud, be sure to throw it on the grill at max temp before you get started.. I always use a GBFH for stubborn things like this. we have lots of interference fits in the grader and paver world.
 
If I had the Cs off, I'd be throwing on some of the super sweet kingpin stuff that Reid has for those axles :D

.005 will be a gracious plenty, even .002 to .003...or a nice, snug slip fit like Jody said. It's going to have the hell welded out of it anyway and it won't go anywhere.
 
I got off work at 6:00 this morning, came home and walked in the shop door at 6:20. I went after the C with a combination of a cylinder hone, and some probably 80 grit sanding screen tape, then hit the tube with a 4.5” 36 grit flap wheel and some more sanding screen tape. I compared the measurements between my Starret inside mics and my Hobo Freight calipers and decided to go for it.

Since I already had on my swim trunks and Hey Dudes I put on my best safety squints and beat the bastard on there with a 4lb. hammer because by Gawd it’s Independence Day! It’s on there and it’s within a half of a tenth of a degree of the other one. ‘Merica f**k yeah! Suck on that you Brits!

Now it’s 7:52 and I’m taking a crap and going to bed! Happy Independence Day you ungrateful Colonials!

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