Gear Pullers

[FarmerHR]

I had an experience that helped me and I would like to share with this site in the hope that it might help someone.
I have a 48 8n with front mount distributor converted to 12 volts, The right rear brake was leeking a little oil, so I desided to change the oil seals in both axles. The right axle went well. I was able to pull the hub with a three legged puller with no trouble. The left one was a different story. Using the same puller, wrench, force, to apply the load etc, the hub would not budge. I tried hitting it under load, using my best penetrant, leaving it under load for days etc. No success.
I have a two leg puller that has a 24 threads per inch screw one inch in diameter. Decided to try it because of the finer thread and larger screw. The three legged puller had 5/8 screw with 10 threads per inch acme thread.
Using the same 18 inch wrench to apply the same load, the hub came off on the first try.
I decided to determine the amount of thrust that was being applied to the end of the axle. Using the formula from the Machinery Handbook, the second puller was putting on nearly three times the trust of the first puller. I knew the trust woud be better because of the fine thread and larger diameter, but did not realize it would be that much better.
Hope this helps some one.
Thanks,
FarmerHR

 

[Anonymous-0]

farmerhr,
Thanks for the tip. I never considered a fine thread for added pull. I'll stuff that away in the back of my mind. Anything to make my life easier is always good to know.

 

[TheOldHokie]

(quoted from post at 04:26:36 12/26/10) I had an experience that helped me and I would like to share with this site in the hope that it might help someone.
I have a 48 8n with front mount distributor converted to 12 volts, The right rear brake was leeking a little oil, so I desided to change the oil seals in both axles. The right axle went well. I was able to pull the hub with a three legged puller with no trouble. The left one was a different story. Using the same puller, wrench, force, to apply the load etc, the hub would not budge. I tried hitting it under load, using my best penetrant, leaving it under load for days etc. No success.
I have a two leg puller that has a 24 threads per inch screw one inch in diameter. Decided to try it because of the finer thread and larger screw. The three legged puller had 5/8 screw with 10 threads per inch acme thread.
Using the same 18 inch wrench to apply the same load, the hub came off on the first try.
I decided to determine the amount of thrust that was being applied to the end of the axle. Using the formula from the Machinery Handbook, the second puller was putting on nearly three times the trust of the first puller. I knew the trust woud be better because of the fine thread and larger diameter, but did not realize it would be that much better.
Hope this helps some one.
Thanks,
FarmerHR

Yes - the finer the thread pitch the greater the pulling force generated for any given tightening torque. This is the fundamental principle underlying the use of a torque wrench for producing a known preload on fasteners like the headbolts. The relationship between applied torque and fastener tension is very dependent on the coefficient of friction between the threads - lubricated threads will produce a significanlty higher pulling force than dry threads. So if using a PTFE type sealer on your headbolt threads remember that you are reducing friction by about 25%!!!

For the mathematically inclined [u:8c5c77b920][b:8c5c77b920][color=red:8c5c77b920]Click here[/color:8c5c77b920][/b:8c5c77b920][/u:8c5c77b920] for all the gory details:

TOH

 

[Fairlane6t9]

The Machinery Handbook is a great tool!!!! I teach CNC machining at the local community college and that book is INDISPENSIBLE!!!! Everything you ever wanted to know (and didn"t want to know) right at your fingertips!!!!

 

[FarmerHR]

THEOLDHOKIE,
Thank You for the excellent thoughts ! I believe you are right on. Interestingly, in this case the screw on the acme thread was phosphated and quite oily. This is probably a pretty good lubrication system. The thread on the the two leg puller was untreated steel with a little oil on it. Probably would get more separation force if a good high pressure lubricant was used. Next time I will try to do that.
Once again thanks for your helpful suggestion.

 

[oldtanker]

One of my finds at an auction this summer was an old hub puller in pretty good shape for $60. After reading the horror stories of removing hubs from the N series tractors I braced for the worst and got my new seals and brake shoes. When I removed the hubs they came off so easy with the hub puller that I was sure they were shot. Nope that fine thread large diameter shaft puller just made it that easy![/list]