Kaos Rulz

Does anyone have a drawing of this reset tool showing dimensions? I am in the need of making one.

aspeed

I made one for my .049 and used it on the .09 and .074. I don't have a wrench for the .15 so am not sure if it will work on that.  I think I had to enlarge the slot to .093"  The OD is .335" with a 90 degree spot drill for the swaging part. The OD could be a bit bigger for the .09 if made specifically for it. I would give you a drawing but am not sure about the scanner thing. 

airraptor

My Feedback: (66)

http://coxengines.ca

check here as they might sell one.

ffkiwi

Cox International has .15 wrenches available for a very reasonable $5.95-these fit the Olympic .15, Sportsman .15, Medallion .15, TD 15 and Special 15 Mk1 and 2-which should cover most people's requirements....

ChrisM
'ffkiwi'

aspeed

I should get off my butt and order one as well as some reeds.I picked up an Olympic in the winter that needs to be opened up. I just can't get excited about the Cox stuff any more. My club requires a muffler and they don't run as good with them. I kind of like the ASP / AP stuff better now. Cheaper and has a throttle and muffler. I got to use up my Cox stuff though.

Kaos Rulz

Aspeed,

I found an 049 reset tool from Cox International at a reasonable price, but they had no tools for the TD 09. You mentioned resetting an 09 using a home-made tool for the 049. Do you thing this store-bought 049 tool will work for the TD09? I'm hoping the ball joint dimentions are the same and the only part of the tool that would not work is the base holding the piston. I can make that fairly easy.
What are your thoughts?

ffkiwi

OK I've just found mine-standby and I'll post some pics shortly -the bad news is that an 049 one won't do the job for you. Very roughly measuring the 049 tool concave depression has been machined with a 1/4" round nosed milling cutter, and the 09 with something larger-probably 5/16". I only have metric ball nosed mills to check with-and the manufacture would have been done with imperial sizes. The slot in the 049 tool measures 3/32" wide, that in the 09 tool 0.120"

ChrisM
'ffkiwi'

aspeed

I just made my own, but without seeing the Cox one, I would think the slot would maybe need to be wider.  It could be ground wider with a dremel cutoff disc if needed. I never use the base, just a machined solid surface is good enough. 

ffkiwi

OK here they are:

Cox International

My Feedback: (10)

Kaos,

If you could send me a reminder email to:

[email protected]

I will send you (when I get back to the office in the morning) a hand-drawing we used to get the 09 reset tool quoted. We did not get them made as we need to buy 500 to get a price that would translate into $12.95 retail pricing and we figure they would be real slow sellers. We are still digesting the 500 pieces of 010 ones we made that "everyone wanted"but are selling at a rate of one per week lol.

Bernie
www.coxinternational.ca

Kaos Rulz

I finished making the tool, to include the anvil base yeterday. Tightned up the piston/conn rod slop and ran the engine today. Everything worked well and the engine again runs like a top. Thanks to everyone for your help! .........and yes, I too was amazed at how hard I had to hit the hammer in order to get results (even with piston on 30# anvil), but what a satisfied feeling when everything works as it is supposed to. Again Thanks!!

ffkiwi

I don't know what steel Cox used for their pistons and rods (and chances are it was different for each)-but it is not beyond the realms of possibility that simply running the engine causes a degree of work hardening in the socket area-even though the copper plating was supposed to prevent this during manufacture. The stresses during running would be of a different but repetitive nature (obviously!) but could induce local work hardening making the socket area less ductile-hence the surprising amount of force required to achieve a good reset with the tool. [just a theory-I have no proof that this is the case.] Conversely-you can overdo it as well -as I have discovered with 049s-and burr the edge of the piston crown-you end up with a really well fitted conrod joint, in a piston that no longer fits the cylinder.........

My thoughts are that the anvils that hold the pistons while you use the reset tool might be improved by fitting a disc of soft-ish plastic (or even cork) in the recess, so that the hammer blows impact more on the ball joint socket, and less on the piston as a whole. Again I haven't tried this-and it might be counterproductive by absorbing too much of the force of the hammer taps-but it's a simple enough experiment to try.

ChrisM
'ffkiwi'

aspeed

Personally I would get the flattest surface for the anvil.  I never used the commercial one, just a flat machined surface on all of mine turning a quarter turn with each hit.

ffkiwi

And an afterthought-does anyone actually know what occurs when the ball and socket joint fit deteriorates? As manufactured, the typical Cox engine little end is a reasonable fit with just a little slop (too much in some folks opinion, but not too bad generally). After a period of use-which will vary depending on how hard the engine runs, the fit loosens up-and progressively gets worse. Serious flyers reset the joint at intervals to get the best performance from their engines.
But HOW does the joint loosen up?
a. Is it the hammering motion intrinsic in the engine's operation causing the socket to expand-ie the ball end of the rod is acting as a tiny hammer on the inside of the socket? [so the socket is becoming elongated in the vertical axis]
b. Is the socket interior wearing during use-so the cavity is becoming larger? [but generally remaining spherical]
c. Is the ball end of the rod wearing, so the ball becomes smaller? [again, generally remaining spherical
d. Or is it a combination of all of these? [potentially giving an 'upside down pear' shape to the socket cavity]

We know in conventional gudgeon pin equipped engines that it is usually the rod that wears (but not always-sometimes the gudgeon pin bosses in the piston wear as well)-and this wear is generally oval-oriented in the vertical plane, so by analogy how does a Cox wear? [complicated by the fact that the piston is free to rotate in use, unlike a gudgeon pin piston]

ChrisM
'ffkiwi'