[How do I?] Advice to Make or repair this (pix)?

[GenesisOfMoY]

This is my problem:

My local machinist says he does not have the means to fix or duplicate this, particularly the blind corner.
It is aluminium. I need to fix about 30 of them with the same problem. The original part is discontinued and out of stock.
I have a few ideas, if you kind folks would indulge me in the pros and cons of each, or just tell me how. heh heh.
1. build a mold, recast it.
2. fabricate a new one from a block of aluminium.
3. machine flat, then perimeter weld in a new set of teeth from a piece of aluminium rack gear.
4. machine key ways in it and fit a piece of steel rack gear. (although, I think this part may be somewhat sacrificial).
5. tig fill in the missing teeth, then re-cut them.
6. try to partial cast it somehow

Thanks in advance.
If there is a better forum for this question, please redirect.

 

[dlane]

Welcome, what is it and what dose it do ?.

 

[DAT510]

Wecome to H-M

With the new forum software I haven't been able to zoom like before, but from what I can see....I'd lean towards TIG to fill in missing teeth and re-cut. I'd think it would be the most efficient, with 30 to do.

I'll take swing....IMHO:
1) Building a mold with the right drafts and compensation for shrinkage would take a fair effort.
2) Manual Machining would be a fun project, but for 30 ........ ? CNC could be interesting.....
3) Could work. (Not knowing it's use) Would there be enough strength with just a perimeter weld?
4) Also could work. Same question regarding enough material for keyways and enough strength?
5) What think I would try.
6) Can you get a partial casting to properly adhere to the original part? I would imagine there would be a weakness at the joint.

Hope this helps....

 

[GenesisOfMoY]

Yes. That helps. Good info.
What the part does; it is part of a transmission in a washing machine. I will post more pictures soon. The short story is that it is pushed back and forth and oscillates the agitator. When the washer is overloaded, it creates too much stress on the part and chews up the teeth.

 

[Ulma Doctor]

the first thing that comes to mind is to mill down all the teeth except for the last tooth on each end, a bit deeper than the root of the tooth
make a rack from steel or bronze and braze or silver solder, or possibly even use high strength epoxy

recasting the part is next, but you'll need to machine that too

 

[brino]

make a rack from steel or bronze and braze or silver solder, or possibly even use high strength epoxy

Maybe can rivet them together.

@GenesisOfMoY , when you add more photos put a scale (ruler) in one to give a better reference.

-brino

 

[Groundhog]

I'm in Salina with a small cnc mill & a tig. I can't tell what the entire part looks like nor am I certain of the size. Send me a private message here & maybe we can arrange something. I would like to look at the part first hand because I think I am missing something. It bothers me that a machine shop said they can't do it. Maybe meet in Abiline?

 

[Silverbullet]

I think with the strength issue it'll keep happening. I'd figure a way to fit in stronger rack ,, steel,, bronze,,?? Stainless ,,,?? . Then the problems mounting. Slid into dove tail slot and some bolts to lock it down. I was always taught to do the best I could . If it's an ongoing problem it won't fix it self. Not every engineer picks the right material so we get to fix there flubs .

 

[GenesisOfMoY]

I do appreciate everyone's comments and suggestions. Keep them coming.
Here are some more pictures, as requested.
I did have another idea to throw out there.
What if I milled the surface like @Ulma Doctor suggested, Then bought aluminium rack gear in narrow strips, say 1/4". Then tig welded them side by side, one strip at a time, till I achieved the total width I need.
@Groundhog I will definitely send you a pm, and meet you in Salina.

 

[Groundhog]

I only live about 50 miles from Genesis so it sounds like we will try to meet up (we have yet to confirm that).
Because my cnc mill is small I'm wondering about milling the existing teeth out forming a rectangular hole. Then make a (stainless?) steel strip to fit into the hole with new teeth. It looks like there might be enough meat to bolt/screw it into place with countersunk fasteners backed up with a one part epoxy (twice the metal to metal strength of standard two part epoxies). https://www.permabond.com/2017/07/21/metal-bonding-epoxy-adhesives-strongest-glue-metal/
Anyone see any reason that this will not work?