Author Topic: Cox resetting tool. (Read 1816 times)

Andrew Tinsley · « **on:** September 08, 2011, 09:32:43 AM »

I have always used the "piston holder" when using the reset tool. I read somewhere that this was not very smart and it was far better to place the piston on a flat piece of substantial plate.
Can anyone tell me why this is? I have reset dozens of Cox pistons using the bored out hole in the reset tool. Just lately I have had pistons that I have had to use some brute force on, non of the gentle tapping with a 2 oz hammer, more like a lump hammer has been required

. Even with such rough handling, there seems to be no piston distortion. So why do folks give the bored out piston holder the thumbs down?

Regards,

Andrew.

kenneth cook · « **Reply #1 on:** September 08, 2011, 03:26:45 PM »

Andrew, it is probably more due to the tool holder not being adequately held down. There is no way to hold and it will bounce around if your not on a substantial surface, plate as you mentioned. Rather than the energy going right to the ball socket, it's being transmitted through the tool and table /surface. It's very important to have this on a very hard and sound surface this way your taps are controlled. My father made me a small little hammer which I just let fall out of my hands onto the tool. It gives great concentrated blows to the resetter and not overdoing it at the same time. It is also important to rotate the resetter as you strike it and hold it as square to the piston as you can. Ken

Andrew Tinsley · « **Reply #2 on:** September 09, 2011, 03:59:05 AM »

Thanks Kenneth,
I do put the resetting tool holder on to a substantial flat surface (an anvil!). Rotating is de rigour and I have managed to get into the tap . ..rotate ...tap routine quite well. So there is nothing wrong with using the piston holder as long as it is on a really firm surface?
I have recently had two pistons that really needed a beating to get back into shape. No tap...tap here, but a quite large blows from a heavy hammer. They both had huge clearances around the ball socket, one indeed had a very small pimple on top of the piston (next stage would have been a hole through the piston!) I assume that there had been some work hardening going on here? Both pistons were eventually reset and both seemed undistorted (at least they went back in the cylinder bore with no complaints!
The two pistons are in engines that I consider to be expendable, so I shall watch how they perform with interest!

Thanks,

Andrew.

AT1984 · « **Reply #3 on:** September 09, 2011, 07:51:01 AM »

Does anyone know of a resetting tool for a Tee Dee .09? I've got one that's kinda "sloppy". There's never been one, as far as I can find...

Allen

Jim Thomerson · « **Reply #4 on:** September 09, 2011, 04:58:12 PM »

There are piston resetting tools for the TD 010, 020, 049/051, and 09. There is not one for the 15, so I have been told. I couldn't tell you where to get an 09 tool, but they come up from time to time on eBay. I have an 09 piston with the rod sticking out the top, so you do not have to make one for your self.

I have reset 049 pistons many times without the Cox holder. You must have a really solid surface, like an anvil, to set the piston on. I now have a holder and use it.

kenneth cook · « **Reply #5 on:** September 10, 2011, 06:09:02 AM »

Early on, I over did the resetting of the ball socket joint. This is a gut retching feeling when you know you've gone to far. The other problem is when you strike the tool off center it feels as though you now have a rough spot while turning the rod. I found a way to fix this by chucking the piston upside down in the drill press. I pour some oil onto the ball socket with the rod in the jaws and turn it on while pulling down on the piston. I know it sounds bad , but I'm not sure what else you can do. It takes a while for it to wear in but eventually it does. I figured at this point, the part was virtually useless. I then clean the ball socket extremely well in solvent usually the aerosol version like brake cleaner. I'm sure running it in probably wouldn't fix it. I've noticed while turning the engines over slowly it appears that the pistons of some of my engines rotate. I figure if this is a part of the design the engine may suffer from a rough spot on the socket joint. For those that have put a nick on the exhaust slits while removing the cylinder, I found a fix for that as well. I had great success using a piece of K&S 3/8 brass tubing about 3" long with some Scotch tape wrapped around the top. This enables the skirt of the piston to fit snug on the brass and you can insert the piston upside down in the cylinder and lap the burr out. This has worked for me several times. It certainly sounds prehistoric to do but it has managed to save me more than one piston sleeve Good luck , Ken.

PaulGibeault · « **Reply #6 on:** September 10, 2011, 11:56:16 PM »

Hi Andrew,
The reason I don't recommend a piston holding fixture is because a long time ago I bought what turned out to be a bad fixture (I think it was a DDD unit , but am not really sure). In any event, after finding out I don't even need a fixture, I never gave it another thought. In retrospect, the current cox fixture has a 'raised' center. I believe the 'bad one' I had was flat. I've never bothered to see if the cox original fixture works well although I suspect it does. I think the raised center is right & the flat one is wrong...
Even when I slightly 'over-peen' the socket joint, it mostly results in the need for a few minutes break-in rather than a junk part. I use a regular 16 oz carpenters hammer, but just lots of little taps while rotating the tool. It seems to work fine. Lots of little taps is the key. Several different methods work for different people, use what seems to work for you. I can't say my way is best, but my way does give me VERY consistent results & I like that part. Good Luck!

Cheers, Paul Gibeault

Larry Renger · « **Reply #7 on:** September 11, 2011, 04:57:48 PM »

The raised center of the Cox unit is the way to go if you can get one. What you DON'T want to do is put pressure on the outer rim of the piston. I usually set the piston holder on a cement sidewalk, then do the tap and rotate thing. It is really hard to go too far. A bit of oil and wiggling to get it moving, then just run it. I also find that tightening the piston just twice is good forever. By then it is worn in to a nice polish inside the cup and outside the ball, and oil does the rest.

George · « **Reply #8 on:** September 17, 2011, 12:03:33 PM »

Quote from: AT1984 on September 09, 2011, 07:51:01 AM

Does anyone know of a resetting tool for a Tee Dee .09? I've got one that's kinda "sloppy". There's never been one, as far as I can find...

Allen

Allen, you're going to find this hard to believe...

Some years ago, I bought a Black Widow at my LHS. When I got it home, I found a complete .09 resetting tool included in the Black Widow box. My guess is that when Cox moved from CA, someone needed to get rid of some parts.

At the time I did not have a TeeDee .09, but later acquired three.

So yes, they made them.

George

Dave Rolley · « **Reply #9 on:** September 17, 2011, 07:21:49 PM »

George,

What is the radius on the end of the tool?

Dave

Jim Thomerson · « **Reply #10 on:** September 19, 2011, 04:10:04 PM »

I heard somewhere that the guys flying TD 049s in speed would put some jeweler's rouge down in the hole while loose, then set the rod too tight and wiggle it around until it was properly lapped in, then wash the jewelers rouge, etc. out and go fly.

Author Topic: Cox resetting tool. (Read 1816 times)

Andrew Tinsley

Cox resetting tool.

kenneth cook

Re: Cox resetting tool.

Andrew Tinsley

Re: Cox resetting tool.

AT1984

Re: Cox resetting tool.

Jim Thomerson

Re: Cox resetting tool.

kenneth cook

Re: Cox resetting tool.

PaulGibeault

Re: Cox resetting tool.

Larry Renger

Re: Cox resetting tool.

George

Re: Cox resetting tool.

Dave Rolley

Re: Cox resetting tool.

Jim Thomerson

Re: Cox resetting tool.