Help with Input shaft pin - RC-Monster Forums

luvsrc · **Help with Input shaft pin -** 04.13.2007, 03:49 PM

Hi guys I was practising today and the pin on my input shaft got broke any suggestions to make it stronger? thanks

ClodMaxx · 04.13.2007, 03:54 PM

i've heard of guys snugging a 2mm allen wrench (cut to fit) in it's place.

BrianG · 04.13.2007, 03:54 PM

There was another thread recently that mentioned that. IIRC, they mentioned something about using the shaft from an appropriately sized drill bit...

Finnster · 01:46 PM

Quote:

Originally Posted by BrianG

There was another thread recently that mentioned that. IIRC, they mentioned something about using the shaft from an appropriately sized drill bit...

I did the hex key trick a while back, but just sheared it clean off last week.
This time I drilled out the holes a bit bigger and put a drill bit shaft thru instead.

I was going to use green locktite (max str bearing retainer formula) on the gear and shaft as well, but I got impatient and just went with the drill bit.

If it breaks again I will use the locktite, and possibly drill bigger and tap w/ 3mm to use a driveshaft thru pin. Don't want to go too big and weaken the shaft, but I think it would take it.

zeropointbug · 04.14.2007, 03:25 PM

Finnster, was your hex that you used very tight in there? If it's not in there very tight, the strength of it will be severely compromised. I think it should only be able to be put in with a hammer, or a vice (tighten it up). How was yours?

Finnster · 04.15.2007, 08:28 AM

Quote:

Originally Posted by zeropointbug

Finnster, was your hex that you used very tight in there? If it's not in there very tight, the strength of it will be severely compromised. I think it should only be able to be put in with a hammer, or a vice (tighten it up). How was yours?

I can't recall for sure what size now (2mm think tho), but yes, it was very tight and had to be forced thru w/a hammer. It was a real bastard to get thru :)

I have a 8XL running on 4S and 5S. Lots of TQ. Slipper is kept pretty tight so it doesn't slip and heat up too much. Overall I'm not that hard on the truck tho.

ssspconcepts · 04.15.2007, 09:24 PM

Quote:

Originally Posted by Finnster

I can't recall for sure what size now (2mm think tho), but yes, it was very tight and had to be forced thru w/a hammer. It was a real bastard to get thru :)

I have a 8XL running on 4S and 5S. Lots of TQ. Slipper is kept pretty tight so it doesn't slip and heat up too much. Overall I'm not that hard on the truck tho.

Thanks...its good info to have...now we have a bench mark for the 2mm key:027:

ssspconcepts · 04.15.2007, 09:25 PM

Quote:

Originally Posted by Finnster

I can't recall for sure what size now (2mm think tho), but yes, it was very tight and had to be forced thru w/a hammer. It was a real bastard to get thru :)

I have a 8XL running on 4S and 5S. Lots of TQ. Slipper is kept pretty tight so it doesn't slip and heat up too much. Overall I'm not that hard on the truck tho.

Now wouldn't it be nice if they came with the mod....

ssspconcepts · 04.14.2007, 03:27 PM

Quote:

Originally Posted by Finnster

I did the hex key trick a while back, but just sheared it clean off last week.
This time I drilled out the holes a bit bigger and put a drill bit shaft thru instead.

I was going to use green locktite (max str bearing retainer formula) on the gear and shaft as well, but I got impatient and just went with the drill bit.

If it breaks again I will use the locktite, and possibly drill bigger and tap w/ 3mm to use a driveshaft thru pin. Don't want to go too big and weaken the shaft, but I think it would take it.

Wow...what are you running that you sheared the 2mm hex key?

zeropointbug · 04.14.2007, 04:50 PM

I don't really think having a more powerful motor than a XL motor is going to put anymore stress on the pin. Only so much torque can be put through the transmission anyways, simply because too much will just flip the truck.

Weight, length, and front/rear mass ratio, and CG impact how much torque can be put through the system.

ssspconcepts · 04.14.2007, 06:28 PM

Quote:

Originally Posted by zeropointbug

I don't really think having a more powerful motor than a XL motor is going to put anymore stress on the pin. Only so much torque can be put through the transmission anyways, simply because too much will just flip the truck.

Weight, length, and front/rear mass ratio, and CG impact how much torque can be put through the system.

You are right...sorta...but weight of the truck and your slipper will significantly influence how much torque is transferred to/from the input shaft and eventually passes on to the rest of the drive-train. There are a lot of factors that influence how much torque is able to make it from the motor to the tires.

ssspconcepts · 04:21 PM

Quote:

Originally Posted by luvsrc

Hi guys I was practising today and the pin on my input shaft got broke any suggestions to make it stronger? thanks

Assuming you completely sheared the pin the secures the input gear to the input shaft follow these steps:

1 drill out the old retaining pin from all parts.

2 find the next size allen key/wrench that is just barely too big to fit in the holes you just cleaned out.

3 take a dremel with a cutting wheel and ever so slightly grind some of the edges off of the allen key/wrench...keep doing this until you can eventually force the allen key/wrench into the holes. It stands to reason that when grinding the key/wrench, make sure you grind more from the front (point of insertion) and less from the rear....kinda like a tent peg.

4 cut the key off at the gear collar and grind & file to perfection.

5 for added retention, carefully apply a dab of JB Weld on both sides where the new pin (allen ke/wrench) is visible. let it dry/cure per instructions.

6 clean and file to perfection using fine jewelers file.

Information on JB Weld:

http://jbweld.net/products/jbweld.php

ssspconcepts · 04.13.2007, 04:23 PM

Quote:

Originally Posted by luvsrc

Hi guys I was practising today and the pin on my input shaft got broke any suggestions to make it stronger? thanks

By the way...I have bullet proofed two input shafts to date and wanted to let you know that it is a pain in the butt:028: . But it is worth the effort once it is done.

zeropointbug · 04.13.2007, 06:31 PM

LuvsRC, once I get my parts for my truck early this week, I will do the pin mod right away and I'll post the results for you... if you can wait that long.

BTW, you don't need to drill out the pin.... just take the gear off, and get somethign smaller than the hole to hammer the pin out. I agree though, using an allen wrench is the best bet, I think that's what I'll use, because you can easily take away material from those edges.

ssspconcepts · 04.13.2007, 08:52 PM

Quote:

Originally Posted by zeropointbug

LuvsRC, once I get my parts for my truck early this week, I will do the pin mod right away and I'll post the results for you... if you can wait that long.

BTW, you don't need to drill out the pin.... just take the gear off, and get somethign smaller than the hole to hammer the pin out. I agree though, using an allen wrench is the best bet, I think that's what I'll use, because you can easily take away material from those edges.

I recommend drilling out the hole...this serves two purposes:

1 makes the hole just a tad bigger for a larger/stronger hex key.

2 cleans the metal so the JB Weld will stick better.