Securing a gear on a shaft without pressing it on

I have considered shrink fitting it. I'm not sure if the gear would expand enough for it to slide on if heated in an oven. In thinking about it I don't think I want customers around the car with a torch. You and everyone here has enough sense to stay away from the flammable transmission fluid, but unfortunately there will be that one person that burns his garage down and I'll have a lawsuit on my hands.

It very difficult to write instructions that everyone can or will follow. I've had two customers literally destroy their transmission by using the bolts to pull the tail housing on. In my instructions I have in big red letters not to pull it together with the bolts and how to easily raise the shift rail so it will go together. But, no matter how I write the instructions I'd say most don't read them.

Including a piece of aluminum tubing is a good idea.
 
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In my mind there is no way to account for the ineptitude of all your possible customers. Seems safety is the number one liability issue you have to deal with. With that being said a high temp/oil resistant locking compound looks like the best approach. Add a disclaimer about improper application of said compound causing premature failure of component.
 
I used to sell quite a bit of racing kart engine parts mail order. With a specialty product your best defense is actually talking to the customer on the phone. Well written installation guides are essential too. But most of all having a contract that limits your liability is the most important of all.
 
I agree safety is number one. People come from different backgrounds and I can't expect them to have my knowledge. If they did they wouldn't be sending me their parts to modify. But reasonably I should expect some basic knowledge if they were able to pull their transmission apart and send me the housing. In over 500 mods I've done for people only two have had problems. One of the two called me and tried to blame it on me. I told him I had in big red letters on my instructions how to solve them problem in just a few seconds. He said he didn't get any instructions. I asked how did you get my phone number to call me then. He changed the subject quickly.

I guess I should look into putting a disclaimer in my instructions. It might save my behind down the road.

I just ordered some loctite 620 from amazon prime. It will be here Wednesday.
 
alloy said:
I agree safety is number one. People come from different backgrounds and I can't expect them to have my knowledge. If they did they wouldn't be sending me their parts to modify. But reasonably I should expect some basic knowledge if they were able to pull their transmission apart and send me the housing. In over 500 mods I've done for people only two have had problems. One of the two called me and tried to blame it on me. I told him I had in big red letters on my instructions how to solve them problem in just a few seconds. He said he didn't get any instructions. I asked how did you get my phone number to call me then. He changed the subject quickly.

I guess I should look into putting a disclaimer in my instructions. It might save my behind down the road.

I just ordered some loctite 620 from amazon prime. It will be here Wednesday.
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I sold go-karts and parts so super careful about liability. The key phrase you need is "mandatory arbitration". Stops the ambulance chasers in their tracks.

Disclaimer:

I am not liable for any advice given on a computer forum. Always seek competent legal advice from a qualified lawyer;)
 
alloy said:
I have a steel speedometer gear I need to secure on a shaft inside an automatic transmission. I can machine it for a light press fit and in the instructions say use a piece of aluminum tubing and a soft hammer totap it on, but in the real world a customer will use steel tubing and their splitting maul to install it.
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If you can get the right diameter of tubing, and cut it to suitable length, and fit the striking end with a stepped wood plug...
then using excessive force would splinter the wood striking surface and maybe common sense would perfuse the installers' thoughts.

Even the wrong diameter, after forcing a BB through it, might work. Or, instead of aluminum, perhaps you could make
a PVC pusher tube?
Stepped plug and controlled tube length ought to be quick on a lathe. You want the wood to stop in contact with the
end of the shaft, of course, so that's what determines the plug/tube measurements.
 
Come on! Hammering it on is so Mickey Mouse! And so is gluing it on.

Work out a way to secure it mechanically.
 
I feel Loctite would be an acceptable method, much better than hammering for sure, as long as the surfaces are clean
I also would bet that JB weld would stay on too, but I have no affiliation with them, just a satisfied customer
Mark
 
After machining the ID of the gear there isn't much wall thickness. If I did put set screws in at a 45 degree angle they would have to be 4-40 set screws. Problems I see with that is breaking the tap, lack of holding power, and customers having problems with tightening them.

JB weld might work, but it comes back customers applying it. I use JB weld to seal the aluminum sleeve I make in the housing. I've never had a failure in 11 years of doing this.

I just talked to a Henkel application specialist. I described the application then the first thing he said was to call the manufacturer of the automobile. So I politely explained this is a custom application.

He said I can use 609 for a slip fit up to. 003. Or use 680 for up to. 01. I need concentricity so I ordered some 609 and I'll return the 620 I bought.

He made sure to tell me this is permanent. To get the part off I'd have to heat it to 450 degrees which is perfect. He also said to mechinicially abrade the surfaces with a wire wheel and use acetone to clean it. And wait a minimum of 24 hours before using it.

I'm sure there will be that one customer that won't follow the directions I supply, but hope most will read the instructions.

As the old saying goes, "you can lead a horse to water, but you can't make him drink".
 
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