353 Fail

[Ketchup]

Is that limited to removable transfer cap cylinders?? Or others as well? Just wondering if they're plated with the caps in place causing stress/tension that is relieved once the caps are removed.....The caps causing tension that is, not the plating process.

I’ve run into it porting AM 372 cylinders mostly. One 346. No transfer covers. They tighten up on the mandrel though I’ve never had one stick completely. But they rub the piston on the sides of the transfer lowers. Especially if you remove a lot of flange. I think @srcarr52 mentioned a similar issue years ago.

I’ve always wondered why 353 and 359 had such a large obstruction at the lower. Maybe the casting is unstable without it.

 

[Stump Shot]

Did you cut the base outward or inward ?

I’m wondering if you cut in, mayhaps the pressure of moving in towards the center helped move the thinned material ?

Second thought is that cylinder extension looks like you cleaned it up a little. Maybe the slap of the start of the interrupted cut pushed some things around ?

Direction of cut was inwards.
I cut the extension after the base operation and slid the mandrel on afterwards.

 

[Stump Shot]

I’ve run into it porting AM 372 cylinders mostly. One 346. No transfer covers. They tighten up on the mandrel though I’ve never had one stick completely. But they rub the piston on the sides of the transfer lowers. Especially if you remove a lot of flange. I think @srcarr52 mentioned a similar issue years ago.

I’ve always wondered why 353 and 359 had such a large obstruction at the lower. Maybe the casting is unstable without it.

That obstruction is material for the screw hole on the opposite side I believe.

 

[Stump Shot]

At any rate, I couldn't see sending it half way across the country as it turned out. Waiting a week for a 346xp cylinder seems a small price to pay now, rather than later. Besides, it will run a little better in the end as well, so that's another positive.
In the end this may have to be chalked up to regular plain old chit happens. Whereas it would be better if it were a learning event instead, so I set it on my shelf so I can ponder it over from time to time when I see it.
Appreciate the responses guys, keep them coming.

 

[Canadian farm boy]

Just curious but how much material were you removing with each pass on the lathe?

 

[NateSaw]

Just curious but how much material were you removing with each pass on the lathe?

Great question!

 

[srcarr52]

I’ve run into it porting AM 372 cylinders mostly. One 346. No transfer covers. They tighten up on the mandrel though I’ve never had one stick completely. But they rub the piston on the sides of the transfer lowers. Especially if you remove a lot of flange. I think @srcarr52 mentioned a similar issue years ago.

I’ve always wondered why 353 and 359 had such a large obstruction at the lower. Maybe the casting is unstable without it.

I had AM cylinders shrink after they've been heated up. I've never seen one shrink from cutting just the base.

 

[Stump Shot]

Just curious but how much material were you removing with each pass on the lathe?

.005" American