Number of FP Motors

[Kevin Ray]

We dealt with that issue a couple of years ago. We milled down the casing on the gearbox of the globe by .25". We then pulled out the one level of planetary gears and increased the speed to something like 450rpm if I remember correctly. We did all the stats on it and have it in the shop somewhere. You do lose the proportional amount of torque however.

[AdamHeard]

A few mentors on 254/968 decided welding the two stages and grinding off the gears would be a good method. They did it to one of their own, but didn't end up using it so they just let us use it. Worked out great for us and it only took the Ames Fabricator 20-30 minutes.

[Andy L]

How do I remove the gearbox, I just got into our shop and can't find any way of taking out the pins holding it on

[WilkesU]

You have to press the pins into the body of the gearbox. You will feel them release/drop in when they get deep enough. Then it is just a matter of pulling them apart (should not require any force)

[Kevin Sevcik]

Originally Posted by Andy L

We have a spare Globe motor lying around our shop somewhere that I'll take a look at next time I'm in there. Can anyone elaborate on exactly how to take out out a stage without welding, milling, or anything that uses anything more than basically hand tools?

Andy,

I can't think of any sane way of dropping a stage without welding, milling or some such. If you're in a real crunch, I'd just make all the preparations for welding two stages together and plan on being first in line at the Machine Shop on Thursday morning. I suppose if you're attempting this on the stage right out of the motor then you could try degreasing the pinion on the motor and the carrier above it and fusing them with JB-Weld or some industrial strength metal-metal epoxy, but I wouldn't want to think of that as more than a temporary solution, to be replaced with a more permanent solution when you have access to a welder. You might have more success at it if you try this with the next stage up from the motor and simply degrease the gears and fill the entire stage with JB-Weld or some such, and then dremel off the teeth of the planet gears and any excess JB weld so the whole mish-mash spins freely inside the ring gear. This would atleast spread out the load a fair piece. That's the only method I can think of aside from hack/chopsawing the ring gear to length or mechanically munging up the planets so they don't spin and stay fixed around the sun.

[Andy L]

we've tried pushing out the pins and drilling them out, we've got them almost all the way out but theres something right at the end that is stopping us. Any more suggestions on how to get these pins out.

[AdamHeard]

Originally Posted by Andy L

we've tried pushing out the pins and drilling them out, we've got them almost all the way out but theres something right at the end that is stopping us. Any more suggestions on how to get these pins out.

They are quite easy to push out with a punch (even a centerpunch or drill bit). They fall into the gearbox at first, but if you then push them too far after they are already free they can jam into the guts. We had that happen to one and it was a royal pain.

[Andy L]

well, we ended up drilling out the pins and we'll probably tap them and use set screws to hold the gearbox on. We are most likely going with the welding method but we plan on preparing the other one just in case the weld breaks.

[Kevin Sevcik]

Just remember to weld the stage closest to the motor that you can, since that's under the least load. If you can assemble things such that there's still a few planets in place but your welder can still tack the stages together, it'll help keep things aligned and reduce binding in your final assembly.

[AdamHeard]

Originally Posted by Kevin Sevcik

Just remember to weld the stage closest to the motor that you can, since that's under the least load. If you can assemble things such that there's still a few planets in place but your welder can still tack the stages together, it'll help keep things aligned and reduce binding in your final assembly.

That's whats they did at SD. They welded the planets on the removed stage in place, and ground off the outer teeth.

[Kevin Sevcik]

Originally Posted by AdamHeard

That's whats they did at SD. They welded the planets on the removed stage in place, and ground off the outer teeth.

That's probably a better option unless you need weight or don't have access to a grinder.

[Andy L]

I just want to clarify about something we just did. We took the gear that is on the motor (sun gear?) and welded it to the plate with the sun gear of the next stage. We removed the first stage's planetary gears altogether. Did we do everything alright?

[Kevin Sevcik]

Originally Posted by Andy L

I just want to clarify about something we just did. We took the gear that is on the motor (sun gear?) and welded it to the plate with the sun gear of the next stage. We removed the first stage's planetary gears altogether. Did we do everything alright?

Provided everything is properly aligned, that will work fine. Just make sure everything runs smoothly when it's all reassembled.

[Andy L]

We used JB-weld the entire time at silicon valley and it didn't break the entire three days.

Thank you everyone for the help

[EricVicenti]

Originally Posted by Andy L

We used JB-weld the entire time at silicon valley and it didn't break the entire three days.

Thank you everyone for the help

Hah, we have had a bad experience with JB weld recently. The 4-40 threading of one our fisher price motors got stripped. We dirlled it out and replaced it with 6-32 threading, but there wasn't enough tapped depth to work at all. So we ended up JB-welding it to the andymark planetary gearbox, which worked until it snapped of in Portland. We then replaced the JB weld with more JB weld, and epoxy on the outside, which didn't work at all. Then we put 8-32 bolts in to prevent the motor from spinning around, and proceeded to secure it in place with large amounts of hot glue and zip ties. We subsequently bought a handful of fisherprice motors from ifi, and a new gearbox from andymark, and replaced it all at SVR. (phew)

Back on topic, team 100 originally used globes on their accumulating mechanism (rollers on top and bottom). At portland it was rather slow, so they replaced it at SVR with the banebots motors, (I think with small banebots gearboxes as well). We asked them about it and they said it delivered just as much torque while being twice as fast. They were #1 seed, and went on to win SVR as the competition's best hurdler.