Gear Size ID for Missing Worm Wheel Gear

[ChandlerJPerry]

I am pretty unfamiliar with gear specs and sizing. I have run into this problem with a newly acquired milling machine in the quill feed gearbox. Unfortunately someone took a grinder to this gear for the manual fine quill feed and removed all the teeth. I would like to restore the function if possible, however there is no manual or parts available for this machine. Therefore I'm in the predicament of needing to identify what the appropriate gear is and try to replace it. I am also uncertain of whether it would be a helical or spur gear. Would it be possible to measure the worm somehow to determine what the correct choice is? I also posted this in the gear hobbing/machining forum to get some more eyes on it

 

[matthewsx]

Bridgeport clone? Check out HW Machine.

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John

 

[ChandlerJPerry]

Bridgeport clone? Check out HW Machine.

Home

Your trusted source for Bridgeport Machine Replacement Parts and Services. We're the best place to get metalworking parts & services online!

machinerypartsdepot.com

John

Unfortunately from what I can tell I think this mill is a unique design. The head is completely different from any style of Bridgeport I've seen. If it is a clone that would be great, but I can't ID what it's a clone of.

 

[matthewsx]

Well, that’s a bummer.

If it was mine I’d be trying to figure out why the previous owner modified it, there might be some underlying reason that would keep me from trying to repair it.

As for figuring out what the gear should be, careful measurement of the one it meshes with should provide some insight. Machinery’s handbook is a good source for gear info.

Sorry I couldn’t be more help.

John

 

[Ischgl99]

This article gives a good explanation on the calculations involved to figure out what gear was in there.

Understanding worms and worm wheels | Gear Solutions Magazine Your Resource to the Gear Industry

gearsolutions.com

Since the worm gear for the rapid downfeed is helical, I would suspect the one for the fine feed would be too. It might even be identical to the one missing. I haven’t run the calculations, but it might not be possible to fit a spur gear in that space and have the correct ratio on the fine feed dial if it was meant to be helical.

Since the machine was made in Japan, I would suspect the gears to be metric, you can confirm that by measuring the spur gear and calculating the module or DP and see if it is closer to a standard size of one or the other. If that one is metric, then the one you need to make is likely metric as well.

Seeing this has given me the idea to see if I can convert the rapid downfeed on my Burke Millrite to the same hybrid system. It might be more work than it is worth, but at least it would be an interesting design challenge.