Get a gear on the Fisher Price

[Lesman]

Hi, our team decided to get a banebots gearbox for our fisher price and have had some trouble using it. After a long battle with the gear that is already attached we managed to break it off (chisel, heat, dremel, pliers, hammer). The shaft was still straight and it was still workig. Sadly while attempting to get the new gear on we bend the shaft running through the motor, effectively ruining it. We placed the motor in a clamp, put the gear on the end and pressed them together, we tried to keep everything aligned as much as possible but that did not work. Does anybody have a suggestion? We would really like to use these gearboxes. We do not have any sort of press (arbor or otherwise) though we could get a small one (1 ton press at sears = $88) if we must. Thanks!

[vivek16]

1. NEVER EVER try and press on a gear without supporting the shaft itself (I drilled a tiny pocked into a small block of metal and used that on the back end of the shaft). The bearings in the fischer price aren't meant to take loads in that direction.

2. Make sure that the bore on your gear is right. I forget the exact size (I'm fairly positive that it's a 30 or a 32, measure the smooth part of the shaft to make sure). The splines on the shaft work real well for pressing on a gear.

With the right bore on the gear and the shaft supported, we were able to tap on the gear with a medium sized hammer. You'll want a socket or some sort of spacer to get the gear past the tip of the shaft.

EDIT: Our application was for a custom gearbox but it worked beautifully and no slippage occured. Use some medium-high strength loctite on your shaft.

-Vivek

[Cory]

There is a thread from 2008 on various methods to do this. I would search for it.

[Lesman]

Originally Posted by vivek16

NEVER EVER try and press on a gear without supporting the shaft itself (I drilled a tiny pocked into a small block of metal and used that on the back end of the shaft). The bearings in the fischer price aren't meant to take loads in that direction.

-Vivek

We did have is supported, one side of the clamp was pressing against the back end of the shaft. And the gearbox was made specifically for fisher price motors. I think we may have just been a little rough with the motor.

[vivek16]

I would re-check the bore on your gear. Even if you are 110 percent positive, just do it. Holes get mis drilled sometimes. I know that I broke 4 motors in the summer trying to press a misdrilled gear onto a fp motor. Very painful experience.

good luck, Vivek

[IndySam]

Originally Posted by vivek16

I would re-check the bore on your gear. Even if you are 110 percent positive, just do it. Holes get mis drilled sometimes. I know that I broke 4 motors in the summer trying to press a misdrilled gear onto a fp motor. Very painful experience.

good luck, Vivek

Viv is right, the BB540 shaft is smaller than the FP. If you try to press that on you will have a disaster.


An arbor press is the best and safest way. See if a local machine shop will let you use theirs, or most good auto repair shops will have one too.

If you decide to purchase one you wont regret it.

[DonRotolo]

For an arbor press, check with Harbor Freight.

[MrForbes]

If the fit of the gear is right, then using a hammer and some type of round driver, and properly supporting the rear end of the motor shaft, should work fine. A press is nice, but should not be necessary.

Also the FP gear is sintered, isn't it? a good whack of a big hammer on a chold chisel, placed between gear teeth, with the gear laying on a solid metal surface, should split it easily.

[R.C.]

Someone really needs to make a video of this and upload it. Many teams have pm'd me the same question over the years. Or could anyone take some pics of this in action and I could upload it. Thanks to anyone that would like to do it.

[Justin Stiltner]

From the original bane bots thread back in 2006
http://www.chiefdelphi.com/forums/sh...ad.php?t=41335
Check out post #18 where I discuss how to install the gear onto the shaft. the whole thread is a good read on these gearboxes. Read from #18 on at least as it discusses a few changes if you are using some gearboxes.

[Lesman]

Alright, thanks for all of the help! I'll try to videotape it and put it up on youtube. If it goes well...Then again, if not, it can be a "what not to do" video.