Fray Milling Head With Broken Worm Gear

[NikolaiBorjeski]

A while back I got a Fray Model 1-1/2 mill with a Type 4 head. After removing the head to give it a clean up I noticed that the worm gear that's used to adjust the angle has many teeth broken off. Obviously it's been broken a few times in the past, and the previous owner clocked it at a different spot so the teeth would still engage.

This still gives me close around 60 degrees of rotation with full tooth engagement, but I'm scared it might break off again and damage something more important.

Does anyone have any advice on a repair? I don't have any hobbing experience or equipment, but I do have a lathe and I'm reasonably good with a tig welder.

From what I can gather it's different from a Bridgeport gear.

 

[markba633csi]

You might download some catalogs from gear makers such as Boston gear and Martin gear and see if anything they have comes close.
It looks to me like the gear is somewhat inadequate for the load requirements- if you can retrofit anything larger in there I would try
Of course that means changing the worm shaft also- probably a major engineering exercise
-M

 

[OTmachine]

You could weld up the damaged teeth, turn down the major diameter, grind a flycutting tool to match the remaining teeth’s profile and use the remaining teeth as an indexing mechanism to recut the teeth. Been there before.

 

[NikolaiBorjeski]

I'm not sure if it failed due to bad design or abuse. Perhaps this gear wasn't treated properly.

The worm shaft has a Boston number on it, so it's a good chance the gear is a Boston as well, even though I couldn't see numbers.

I didn't think about using the teeth themselves to index on, that might be possible, though tricky since they're helical.

 

[ErichKeane]

A helical gear is one of the more difficult ones to make yourself, so making your own is probably the key.

I'd suggest doing 2 things: 1- count the number of teeth on the gear. 2- look up the boston gear part # on the worm.

You can use the info from looking up the worm for PA/DP/etc. THEN, just grab a PA/DP gear that matches wtih the right amount of teeth. The mount holes are likely necessary to cut afterwards, but that seems like the easiest way to me.

 

[Nutfarmer]

You can still set tram with out the gear. Just set the bolts with a little more drag. Not easy but it will work.

 

[NikolaiBorjeski]

Seems like looking through the Boston catalogue worked! Appears to be this one, also available from McMaster-Carr. Just needs to have the hub machined off and 4 holes drilled in it, that I'm confident in doing. Now just to get it to Canada...

 

[ErichKeane]

That definitely looks a lot like it! Good job!

From looking at that, Martin Gear has that under `W1230` as their part number if I'm reading this right. it is roughly the same price as Mcmaster everywhere.

Here is a company in Canada that lists it, and seems to have B&M places. Unofrtunately it appears the closet to you is in Sudbury ON (~$375 KM) https://www.sourceatlantic.ca/Product/W1230 ...

That said, that probably means you can order from them?


That said, according to Martin, they have 3 locations in Canada, including 2 in Ontario. 1 is Mississauga, and the other is in Ayr (roughly a 40 km drive!).

https://www.martinsprocket.com/mobile/Locations/Canada.aspx

Might be worth giving them a call to see if there is any way for you to pick one up/order one directly from them?

 

[markba633csi]

One of the benefits of having a US made machine!
Interestingly, I have a 80s Taiwan-made bandsaw that also uses Boston worm gears
Some things are easier to buy than make even overseas

 

[benmychree]

I have that same mill in my shop, but without the power feed; what is the flange bearing unit above the vertical ways for?