Traxxas Sledge

[mhogan2287]

I got The Traxxas Sledge about 2 weeks ago and this thing is a BEAST the only problem I'm running into is I keep breaking the grub screw on the pinion gear causing the pinion gear to move on the motor shaft while driving any reccomendations for how I can fix this issue? I.e stronger grub screw, different type of grub screw, locktite pinion to the motor shaft exc. What would work best? It is powered by 6s

 

[Rob66]

I got The Traxxas Sledge about 2 weeks ago and this thing is a BEAST the only problem I'm running into is I keep breaking the grub screw on the pinion gear causing the pinion gear to move on the motor shaft while driving any reccomendations for how I can fix this issue? I.e stronger grub screw, different type of grub screw, locktite pinion to the motor shaft exc. What would work best? It is powered by 6s

Got a picture of the problem?

I have beat my Kraton 6s pretty hard and have yet to have a grub screw issue. odd

Also, Welcome to RCT!

 

[Tunedfrog]

Welcome in @mhogan2287 , I a bit confused as to what is breaking? It sounds like to me, if you are running it then it's simply coming loose.
If that's the case, did you use Loctite, and if so did you let it sit for 24 hours?

 

[mhogan2287]

Got a picture of the problem?

I have beat my Kraton 6s pretty hard and have yet to have a grub screw issue. odd

Also, Welcome to RCT!

I'm not gonna lie I've beat the holy hell out of the Sledge it only seems to happen when the motor shaft gets hot thank you glad to be here always lookong for good forums

 

[Rob66]

I'm not gonna lie I've beat the holy hell out of the Sledge it only seems to happen when the motor shaft gets hot thank you glad to be here always lookong for good forums

Sounds like you need to gear down and get some nice fans.

Motor temp should not be above 150f.

 

[mhogan2287]

Sounds like you need to gear down and get some nice fans.

Motor temp should not be above 150f.

Its completley Stock I did just add a motor fan to it before my last run and still had the issue with the grub screw it keeps breaking the tip that meets the motor shaft causing the pinion gear to come loose and slide out of place

Got a picture of the problem?

I have beat my Kraton 6s pretty hard and have yet to have a grub screw issue. odd

Also, Welcome to RCT!

I dont have a picture right now but ill get one and post it here soon

 

[Rob66]

Its completley Stock I did just add a motor fan to it before my last run and still had the issue with the grub screw it keeps breaking the tip that meets the motor shaft causing the pinion gear to come loose and slide out of place

I dont have a picture right now but ill get one and post it here soon

Try a Robinson racing or tekno extra hard pinion.

 

[WickedFog]

Try a Robinson racing or tekno extra hard pinion.

This

 

[mhogan2287]

Try a Robinson racing or tekno extra hard pinion.

Its not the pinion its the set/grub screw that hilds the pinion in place on the motor shaft

 

[WickedFog]

Well, you can buy quality set screws from www.mcmaster.com

 

[Rob66]

Well, you can buy quality set screws from www.mcmaster.com

+1

Flat tipped ones are better. Imho

 

[mhogan2287]

Well, you can buy quality set screws from www.mcmaster.com

Thank you thats exactly what I'm needing is better set/grub screws or something cuz its driving me nuts much appreciated

+1

Flat tipped ones are better. Imho

Yea thats what I've heard but i can't seem to find them especially the hardened ones cuz the sledge is 6s

Welcome in @mhogan2287 , I a bit confused as to what is breaking? It sounds like to me, if you are running it then it's simply coming loose.
If that's the case, did you use Loctite, and if so did you let it sit for 24 hours?

The tip of the set/grub screw that sits against the motor shaft keeps breaking not allowing for it to secure the pinion gear to the motor shaft i did use loctite on the set/grub screw but i have not used loctite on the motor shaft before sliding pinion gear on would that help?

 

[WickedFog]

Thank you thats exactly what I'm needing is better set/grub screws or something cuz its driving me nuts much appreciated

Yea thats what I've heard but i can't seem to find them especially the hardened ones cuz the sledge is 6s

The tip of the set/grub screw that sits against the motor shaft keeps breaking not allowing for it to secure the pinion gear to the motor shaft i did use loctite on the set/grub screw but i have not used loctite on the motor shaft before sliding pinion gear on would that help?

It won't hurt, but it's not going to help much. The motor shaft is a ground and polished surface. So Loctite won't stick to it very well.

If you have a Dremel, you can knock the tip of the grub down a bit. I don't typically have problems with the pointed grubs. Just make sure if you grind on the tip of the grub, don't get it too hot, or you will destroy the hardness of the grub. It's actually best to use a file or stone.

 

[Mrgoodwrench35]

What WickedFog said is what I do to most all my pinion grub screws. The concept of a pointed grub screw seems silly to me unless you are putting a dimple in the motor shaft for it to sit in.

 

[WickedFog]

What WickedFog said is what I do to most all my pinion grub screws. The concept of a pointed grub screw seems silly to me unless you are putting a dimple in the motor shaft for it to sit in.

Most standard grubs have the taper to focus pressure in a smaller surface area. Just like they say a woman's high heeled shoe has the same pressure per square inch as an elephants foot (depending on how big the woman is of course lol). Having a flatter tip doesn't really add any more holding power. It's just spread over a larger area. Essentially, less pressure per square inch.

 

[WickedFog]

I should add that with cheap set screws, that tip will not hold up. With high quality ones, you won't have issues with the small tip deforming under pressure. I have never had a pinion come loose. Use a tiny drop of Loctite, and let it setup a bit before installing the set screw.

 

[mhogan2287]

What WickedFog said is what I do to most all my pinion grub screws. The concept of a pointed grub screw seems silly to me unless you are putting a dimple in the motor shaft for it to sit in.

Yea I've used the flat tip grub screws on other rc's and have had no issues

 

[WickedFog]

I use these
https://www.mcmaster.com/screws/set...tric/metric-alloy-steel-cup-point-set-screws/

 

[ahr43]

Is there a flat milled on the motor shaft for the grub screw to bite into? If so, is the pinion grub aligned so it mates to the milled flat? Is there any grooving on the motor shaft that indicates the shaft is turning inside the pinion until the grub leaves the flat and breaks? Are the threads in the pinion gear cut full length to ensure the grub screw fully engages the shaft? Is the grub screw the correct thread to match the pinion gear threads? Is the wrench used for tightening correct for the grub hex?

Just some thoughts based on personal experience. For what it's worth. Regards. 'AC'

 

[Slick2500]

Clean the grub screw and pinion with brake cleaner, put pinion in position, put a drop of thread lock in the grub screw hole in pinion, put in grub screw and allow to dry for 24 hours.