Removing a worm from a shaft

[mike_lawyer]

Has anyone had experience removing a worm from a shaft?  I need to remove a worm from a shaft from loco to mount on a motor, and I'm trying to figure out how best to do it.  Can it be done with an NWSL puller?  Any thoughts would be appreciated.

Mike

[screeh]

I've used a NWSL puller to replace the plastic worms on motors from Life-Life switcher, takes a bit of patience (especially as I don't have a vice, so I need to to hold the puller, pin, plate and motor in position) but is certainly possible.

[Lemosteam]

Mike,

I use a drill press with a notched stainless plate backing behind the worm and a hardened drill bit just smaller than the motor shaft installed backwards into the chuck.  If it is glued, you may want to use a soldering iron to apply some heat to the worm assuming it is not plastic.  This is a very controlled operation as the press will only move axially.  The NWSL will add a torsional and friction elements as you are tightening the screw.

[TiVoPrince]

Any 
reasonable quality arbor press that can accept hardened steel wire will work.  You will need a nothed pressue plate and some method to stand the plate off the base.  When removing worms from HO motos I sometimes found it necessary to cut away the motors frame and sometimes even the armture to get a good fit in the NWSL Puller.  I have  a hardened steel plate that a friend made for me (although I can't find it at this moment) a couple of bricks on the arbor plate make it stand nicely off the surface.  The arbor press and late will come in mighty handy when pressing the worm onto a ew motor...

[mmagliaro]

I do what Lemosteam does.  I have a milling machine, but a plain old drill press would work.
Get a drill bit just smaller than the motor shaft.  Make a V plate out of the thickest steel you can find that will
let you shove the open "V" in between the worm and the motor housing.
Hang the motor by the plate, under the drill press with your tiny bit in it.  Then lower the head and press the
shaft out of the worm with the drill bit being the push ram.

The trick is to keep the drill bit (or steel wire) VERY short at first.  Only let it stick out of the head 1/8". Just enough
to get the shaft to push that first little bit inside the worm.  Once it moves, you're home free.  The rest of the pressing will
go much easier.

------
I do use a NWSL Puller with the add-on Precision press bolt set.  But there are some shafts which that thing cannot press out.
The push bolts will bend or break before the shaft will push out of the gear.

I have also done it the "poor man's way", using the motor suspended by the V plate in a jewelers vise, and then
using a small drill bit, (or even a paneling nail to get it started!), and hammer - just punch the shaft out of the gear.
It works because the motor is hanging by the gear, so you really don't hurt the motor.

But really....
The drill/arbor/mill works better.    Now that I do it that way, that's the only way I do it.  Some nasty worms, like
the Trix B6, were impossible to get off any other way.

---

[peteski]

Another good topic which was discussed on the late-Atlas forum. Here is my contribution from that thread (photo will only be available for as long as Atlas forum is up). 

For a plate I have also used something else which is much cheaper, quite thin and very hard: used utility knife (box cutter) blades. Almost everybody has them and they are pretty much free (as they are being thrown away). They are made of very hard steel and the are quite thin (0.025").

Here is a photo of a stainless steel plate (0.050") with a slot cut in using a hacksaw and a cut-off wheel in a Dremel tool.

On the bottom is the plate made from a used blade. I first rounded off the ends and the blade (using a grinder) then cut the slot again using a cut-off wheel in a Dremel tool.



For the full thread see http://forum.atlasrr.com/forum/topic.asp?TOPIC_ID=69499

[DKS]

I use just the V-plate from a NWSL puller, since most of the worms I have to remove are too small for the rest of the tool. I mount it in a vice, drop in the shaft, and then drive it through the worm with a broken drill bit and a small hammer.

[pnolan48]

The NWSL puller is a fine tool. But it is not obvious to many newbies to gear pulling that it won't work on the thinner shafts of many motors--the pusher is too thick. I think you can figure out how I learned this with a Minitrix K-4. Nothing like screwing up an expensive remotoring project by squashing the worm gear even a little tiny bit.

[Carolina Northern]

I thought this was well covered, so I didn't post right away, but I didn't see this suggested.
I've used the slot and drill bit method, but the last time I needed to do this, I bought a puller off E-Bay designed for slot cars.
The label says GW/GP Micro. I found it listed from several shops. I seem tor emember it was about 8 dollars.
I've sucessfully used it on worms and flywheels enough to recommend it.
It has a variety of shafts (1,1.5,and 2 mm)and it pushed the parts right off the shafts.

[Lemosteam]

Carolina northern, do you happen to have a picture or a link to a picture of one?  I am interested in looking at the product?

[mmagliaro]

The NWSL puller is a fine tool. But it is not obvious to many newbies to gear pulling that it won't work on the thinner shafts of many motors--the pusher is too thick. I think you can figure out how I learned this with a Minitrix K-4. Nothing like screwing up an expensive remotoring project by squashing the worm gear even a little tiny bit.

True, but if you buy the accessory precision push bolt set for it, then it can push those worms off the smaller shafts (1.0mm and 1.2mm).
The problem then becomes that on some worms, even with the correct sized pushbolt, the worm is so stuck on there that the
pushbolt will bend before the shaft will push out.    Sometimes it works fine.  Sometimes, they are too tight.  The piece of drill rod
in a drill press works when the "puller" fails.

[Carolina Northern]

Lemo,

I'll try to get a picture up later today, but I found one on Ebay - item 271000309834.

Their picture may not be that helpful.

[SkipGear]

This is the one I use. It is intended for micro electric aircraft but has 1, 2 and 3mm shafts...

http://www.horizonhobby.com/products/gear-puller-1mm-5mm-shaft-EFLA212

another option with 1, 1.5 and 2mm pins...

http://www.horizonhobby.com/products/gear-puller-set-micro-1-1-5-2mm-GWSGPMICRO

[Carolina Northern]

Tony,

The second one you put the link to is the one I use. I just got it from a seller on E-bay.