Re Chrome a sleeve
02-20-2002, 04:29 AM
#26
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Re Chrome OS.91 DF Sleeve
Rotaryphile,
I really did not want to put it in a lathe either-I will just use a really small brake hone with the finest stones I can find.
Thanks again,Jackjet
I really did not want to put it in a lathe either-I will just use a really small brake hone with the finest stones I can find.
Thanks again,Jackjet
02-20-2002, 01:12 PM
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Re Chrome a sleeve
The honing of a model airplane engine liner is a very delicate process. A high degree of accuracy is required. Inside diameter, parrallelism and roundess to very tight tolerances have to be maintained. To achieve this requires a high degree of skill. This is an acquired skill requiring lots of practice.
I am hearing about drill presses and brake hones and the first time somebody has attempted it. I can almost guarantee that the liner will end up bell mouthed and oversize around the ports. The plating process will have to be repeated all over again. Remember we are not talking about 1/64 of an inch here and there, we are talking about 0.0001 of an inch out of tolerance and the liner is useless. It is all very well to describe the chemicals required. However when the honing starts measuring has to take place as well. For the cost of inside diameter measuring equipment you could buy a new engine. I have not heard that small detail mentioned yet.
It may seem I am being very negative. I am trying to prevent somebody spending a pile of money on plating and other stuff suggested here, thinking he is going to be able to fix his engine. It is not going to happen!
However, like I said before, if you have an itch to scratch and can afford the money and then throw the liner away, go to it.
Ed S
I am hearing about drill presses and brake hones and the first time somebody has attempted it. I can almost guarantee that the liner will end up bell mouthed and oversize around the ports. The plating process will have to be repeated all over again. Remember we are not talking about 1/64 of an inch here and there, we are talking about 0.0001 of an inch out of tolerance and the liner is useless. It is all very well to describe the chemicals required. However when the honing starts measuring has to take place as well. For the cost of inside diameter measuring equipment you could buy a new engine. I have not heard that small detail mentioned yet.
It may seem I am being very negative. I am trying to prevent somebody spending a pile of money on plating and other stuff suggested here, thinking he is going to be able to fix his engine. It is not going to happen!
However, like I said before, if you have an itch to scratch and can afford the money and then throw the liner away, go to it.
Ed S
02-20-2002, 01:19 PM
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Re Chrome OS.91 DF Sleeve
Ed,
it looks like I will just have to find a new OS.91 piston and sleeve-it seems you can't buy them anymore from anyone................or a new engine-lets see-4 new OS.91DF's= 1 small turbine-I better think on this one............
Jackjet
it looks like I will just have to find a new OS.91 piston and sleeve-it seems you can't buy them anymore from anyone................or a new engine-lets see-4 new OS.91DF's= 1 small turbine-I better think on this one............
Jackjet
02-27-2020, 01:42 PM
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Model Engine Company Of America
Jim
02-28-2020, 07:46 AM
#31
Here is a good article on chroming. https://www.nclra.org/TechTopics/Way.../Chroming.html I always thought it may be a good project to try but never needed it done. I got a few OS motors that were peeled recently and thought it may be a project to try again. I knew/know a guy that did it with a 12V battery IIRC. The wheel cylinder hone would not work well, I am quite sure. An adjustable lap would need to be made up. Maybe a bit of practise on some plumbing tubing would be an idea, to see if it bonds well, or flakes off. An aluminum sleeve looks like it is over my pay scale but brass or steel liners, or even pistons,? maybe not. It does look like more trouble than it may be worth.
