Machinest help

[niget2002]

I have a geared electric motor that a shaft/gear assembly broke. A friend tried to cut me a new shaft, but he can't find his smallest chuck to finish the part. It's been 3 weeks and he still can't seem to find it (he stopped using the chuck a few years ago and stored it 'somewhere' where he wouldn't lose it).

I'm hoping one of the many GJ machinists might be able to help me out.

It's a steel shaft that is .766" long and .095" diameter.

Part of me wants to use it as an excuse to get a small metal lathe, but it's not Christmas so I can't get it approved by the Boss.

 

[OccupantRJ]

If you are drilling a rather small hole, and if you have a non working hand drill around, take the chuck and stub shaft out of the drill and chuck it into a larger drill. This should allow chucking of a small drill size, which by the size of your part, is what you need. Go to a flea market and buy a $5 drill if you have to.

 

[BuffettFan]

Could he make the shaft out of a larger diameter piece of stock? Chuck a piece of 3/8" for example, turn the .095" diameter, then part it off?

Or, As RJ suggested, the double chuck trick if it is a drilling issue.
Pin vises are very affordable for small drill bits as well. $25 would buy you a name brand tool that would be in your size range. Check out MSCDirect.com and search "pin vise".

If you could post a sketch of want you need to have made, I may be able to help out. Something that small would be easy enough to mail.

 

[LXCam]

Now sure what it is you need. But you could buy a gauge pin and cut it down. Drill the shaft and either press fit it in or use a loctite product to keep it secured.

 

[lilredex]

You sure of those dimensions?? You could almost cut off the end of a 3/32" welding rod to get that piece.

Or, go to Lowes drawers and get a pin.

 

[niget2002]

Could he make the shaft out of a larger diameter piece of stock? Chuck a piece of 3/8" for example, turn the .095" diameter, then part it off?

Or, As RJ suggested, the double chuck trick if it is a drilling issue.
Pin vises are very affordable for small drill bits as well. $25 would buy you a name brand tool that would be in your size range. Check out MSCDirect.com and search "pin vise".

If you could post a sketch of want you need to have made, I may be able to help out. Something that small would be easy enough to mail.

I think the pin vise is what he's looking for. He started off with a larger stock and turned it down. He's looking for the pin vise to hold the smaller part to part off the leftover material.

He gave me a sketch, but it really is just a small shaft with the length and diameter I posted. The gears, I already have. They press fit onto the shaft. I'll probably use a touch of loctite to hold them to the shaft if needed.

Now sure what it is you need. But you could buy a gauge pin and cut it down. Drill the shaft and either press fit it in or use a loctite product to keep it secured.

You sure of those dimensions?? You could almost cut off the end of a 3/32" welding rod to get that piece.

Or, go to Lowes drawers and get a pin.

I started off with these two approaches. I couldn't find anything tight enough to hold the gears. It's a rather high torque 1 RPM motor and this gear is in the drive train.

Here's a picture. The phillips screwdriver is pointing at the broken portion

https://photos.app.goo.gl/KvCLnJiZgFY4tYck6

I also called the motor manufacturer, but they don't carry replacement parts. They wanted to sell me a whole new motor for $175.

 

[lilredex]

Assume that is a press fit? You could bump that pin with a welder ( or a chisel) and file it a bit so it could be pressed in tightly. What is that socket thing on the end?

 

[niget2002]

The gear in the picture is upside down. That's a spacer on the gear that goes between it and the gear underneath it. I forgot to mention that part.

To be honest... I'm not sure how it was held in place originally. I'm trying to fix something I never saw when it was working correctly. I'm hoping the new shaft with the gears press fit will fix it.

I have a slightly smaller shaft in there now. When I plug it in, you can hear the gear clicking as it moves on the shaft and skips.

 

[lilredex]

So, if your friend has it next to ready, why not cut it off with a hacksaw, put the piece in a drill press and bring it down on a file. That will both clean up the end and bring it to final length, if really that is important.

To finish it in the lathe, he could make a split bushing to fit the chuck and mount it that. If the pin needs roughing up, do it with a welder or ***** punch as above.

 

[niget2002]

So, if your friend has it next to ready, why not cut it off with a hacksaw, put the piece in a drill press and bring it down on a file. That will both clean up the end and bring it to final length, if really that is important.

To finish it in the lathe, he could make a split bushing to fit the chuck and mount it that. If the pin needs roughing up, do it with a welder or ***** punch as above.

That's a good idea. I'll talk to him about it tonight. Maybe that will work.

 

[larry_g]

https://www.engineersedge.com/roll_pin.htm

Sounds to me like a spring or roll pin would be the correct item to use. A 3/32 pin would be the one to use.

lg
no neat sig line

 

[firebirdparts]

Press fit seems to be unnecessary in that application, unless the two gears were totally separate. If you use a pin, it would make the lubrication needs different, but I don't see that as an advantage at all. Are you 100% sure it was press fit? If so, why?

 

[laser3kw]

Pin Gage link
see above link
but the correct pin and cut to length.
You will need a Dremel tool with a cut off wheel

 

[BuffettFan]

I think the pin vise is what he's looking for. He started off with a larger stock and turned it down. He's looking for the pin vise to hold the smaller part to part off the leftover material.

Question, why not chuck the larger diameter and part off the smaller diameter?
That is how I would do it.

 

[niget2002]

Question, why not chuck the larger diameter and part off the smaller diameter?
That is how I would do it.

I can't answer this. I'm sure he had a reason.

 

[Fueler]

Simplest solution is to not put your friend on the spot. Take your part to machine shop and get it made. Done.

 

[niget2002]

I got a chance to talk to him some more.

He started down his current path thinking he knew where his pin vise was. The part is not turned down to final diameter because he couldn't go any thinner with the chuck he has it on.

As far as chucking a larger piece of material in and turning down just a center portion... he agrees that this would work, and he's contemplated that, but he's trying to not have to start over on the part.

He's a good friend and has helped me in the past. The motor isn't on a mission critical device, so I have a lot of time I can give him.

I've also helped him with woodworking stuff, so it's not like I'm abusing a friendship. He seemed more bummed that he can't find the vise than I was, so I thought I'd take a little burden off and get help elsewhere.

Thanks for the other ideas on where to get something that might work. I have lots of options to try now.