# Bruce



## schoejr53 (Mar 17, 2014)

I am new please forgive my mistakes.  I am wanting to ask a question concerning a hydraulic cylinder that I am rebuilding.  The barrel on one end is egg shaped and stretched approx .100.  I want to fill the inside of the barrel and use my boring bar to return the barrell to standard bore.  I have a old rottler bar with an Offset boring head to allow me to bore at 6.300".  My problem is I have never used it is this manner. Always bored engine blocks that were cast and these will be steel.  what must I do to get a good cut while boring?


----------



## xalky (Mar 17, 2014)

Maybe this youtube video will be helpfull. https://www.youtube.com/watch?v=8qFl67ByDfA&list=TLN7ZNOUNP6geJ6XHshR_3REOr8PP0BYm8

I'd first try to get the eggshaped bore back to round. As close as possible. By any means possible. This might not be practicable to do. You might be better off starting out with a fresh new tube and boring it out to size. Or finding a new or used cylinder. Pictures would help tremendously.


----------



## schoejr53 (Mar 17, 2014)

xalky said:


> Maybe this youtube video will be helpfull. https://www.youtube.com/watch?v=8qFl67ByDfA&list=TLN7ZNOUNP6geJ6XHshR_3REOr8PP0BYm8
> 
> I'd first try to get the eggshaped bore back to round. As close as possible. By any means possible. This might not be practicable to do. You might be better off starting out with a fresh new tube and boring it out to size. Or finding a new or used cylinder. Pictures would help tremendously.



I have put the cylinder in the press and have it as close as I can get.  it is a very very expensive cyl.  my quest is to save it.  I did not realize the introduction was a important as it is.  I have miller 250, hypertherm 45, 12 ton press full compliment of tools.  I only have to fill the last 1 to 1 1/4 " of the cylinder and turn it back to original bore size  6.300".  As this is only fill it has no moving parts I am trying to establish a inner bore for the seal to do its job.


----------



## xalky (Mar 17, 2014)

How close is it to size now? What do you suppose the tolerance has to be? I'd think twice about filling that bore in with weld material. You may never get it right.

If the bore is smooth and not too far out of spec after you corrected the egg shape, maybe the seals will work now. Or maybe you can put an internal stop on the cylinder to limit it's travel. 

The issue is that filling it might warp the cylinder, which will be as bad or worse as it is right now. Then, lets suppose, your having a great day and that it doesn't warp. You have to bore only that section to the correct diameter to match the rest then you have to hone it smooth to match. The whole ordeal is a very tall order indeed. Do you guys have any cylinder rebuilders in your area? we have a few up here. Is it possible to sleeve it and put a slightly smaller plunger inside?


----------



## Tony Wells (Mar 17, 2014)

If there is room, can you make a split ring that will crush the tube back to round? It would take quite a heavy ring to do so. 

If you need a seal to work in the blend area of a welded build up, odds are that you would have some undercutting that would spoil the seal surface. Do you have metalizing capability? You could probably build it up that way and then bore & hone it back to spec. I don't suppose there is enough length to simply sacrifice a bit of stroke and just cut the bad end off? A new piston with the seals located back from the end enough to avoid the less than perfect area?

There are lots of places for this to go sour on you, so think carefully about how you proceed.


----------



## 12bolts (Mar 17, 2014)

Is it possible to flip the cylinder end for end and put the egg shaped section at the opposite end of the stroke?

Cheers Phil


----------



## Dave Smith (Mar 17, 2014)

I would go for an external short thick walled bushing to press the cyl end into to force it to take the oval shape back to round--how thick is the wall of the cylinder--and is there room to press a thick bushing sleeve on the end-?----Dave


----------



## davidh (Mar 18, 2014)

did you say how far out of round you were talking about ?   .010 ? .250 ?
check with your seal supplier for the tolerances allowed with the seal.  they will handle a surprising amount of diameter differences. . .


----------



## jererp (Mar 18, 2014)

Dave Smith said:


> I would go for an external short thick walled bushing to press the cyl end into to force it to take the oval shape back to round--how thick is the wall of the cylinder--and is there room to press a thick bushing sleeve on the end-?----Dave



We had a production job where we pressed a heat treated cam into a cast iron support body. The heat treat operation made the ring go quite out of round, but when pressed into the support, hoop stresses brought it right back into round.  

You may be measuring it oval in the free state, but when the end cap is installed, it may round back up to be functionally round enough for your seal.


----------



## schoejr53 (Mar 18, 2014)

the cylinder is 6.300 inside bore.  I actually turned a sleeve to make the clylinder  back to original.  the cylinder was out of round and at least .0100 oversized.   I turned a sleeve with a wall of .050.  My problem is that I have not figured out how to center up the boring bar to make the cut in the center of the bore so I can insert the sleeve.  so difficult to convey all of the info.  Right now I want to fill the last one inch of the bore with weld.  Then turn the last inch back to original.  I dont know how my boring bar will work cutting steel instead of cast iron.  I know that there are pros out there that do this work so the challenge is to learn.  Part of doing the machinist, welder, bore-er, fix it is the challenge to learn new things.


----------



## schoejr53 (Mar 18, 2014)

Tony Wells said:


> If there is room, can you make a split ring that will crush the tube back to round? It would take quite a heavy ring to do so.
> 
> If you need a seal to work in the blend area of a welded build up, odds are that you would have some undercutting that would spoil the seal surface. Do you have metalizing capability? You could probably build it up that way and then bore & hone it back to spec. I don't suppose there is enough length to simply sacrifice a bit of stroke and just cut the bad end off? A new piston with the seals located back from the end enough to avoid the less than perfect area?
> 
> There are lots of places for this to go sour on you, so think carefully about how you proceed.


Tnx Tony,  I turned a plate at 6.300" and attached it to the bottom of my boring bar then extended the bar down into the bore of the cylinder.  I made a second plate  to attach to the bar at the top of the bar as close to the top of the cyl bore  before it went out of round to act as a top and bottome guide.  Very difficult to work in such tight quarters.  I have an offset boring head and using a replaceable bit in the head.  I have not bored anything this way is there experience out there with this type of operation?


----------

