[Milsurplus] Worm Drive

[Bob Camp]

Hi

I have a 3D printer about 3’ away from me as I type this. 

If you go with a simple printer, you will get a gear that will last for a while (many months). I’ve printed a lot of them. That assumes the gear is designed from scratch for this sort of printer. 2 to 3 mm shafts rules that out.

If you go with a more fancy printer you can do a much better job. Since they are expensive machines that run on expensive materials, the result is not at all cheap. I can do a gear for under $20 plus CAD time. Since there  are two different gears in a set, figure $40 plus CAD. On a fancy machine figure $200 - $2000 per gear, depending on a lot of things. The last stuff we sent out was about $600 after we did the CAD. 

What’s the difference in the printers? $800 to $5,000 for a simple one. $50,000 to $250,000 for a fancy one. Yes the base price is a bit less. There’s *always* this and that you have to buy. (oh, you want *4 tires* with your new car… well that will be extra, our standard model only comes with the spare….). 

I could cut one one the CNC if I added a 5th axis to it. I’d still need the right cutters for the job. Last time I priced a set they were in the $400 region. Not very cost effective for a single pair of gears. 

Bob


On Mar 24, 2014, at 8:42 PM, Bruce Gentry <ka2ivy at verizon.net> wrote:

> Have you checked into 3D printing?  If you gave  the shop a  proper file, the cost could be reasonable. They might also be able to 3D scan the original part for you and edit out the defect. Aside from cost, the big issue is whether the material used for a 3D print would be strong enough to take the load and wear well, and whether the printing process could give a suitable finish.  Mabye not yet, but the time is coming and will be here sooner than we think.  I am considering this for a gear and the dial mask missing from my R-274 receiver.
> 
>     Bruce Gentry
> 
> On 3/24/14 8:21 PM, Bob Camp wrote:
>> Hi
>> 
>> If you only need only one set, and it’s not a standard item with anybody - check your local CNC guys. Somebody around you probably has a 5 axis machine and might be able to do the gears. No matter what you do, unless it’s stock it will cost quite a bit of money. If you have it drawn up in 3D CAD (.stl is a nice format)  that will help the process along. If they have to draw it up first, count on a bit more money spent.
>> 
>> If a quote above $400 is going to scare you do death / send you down another course of action - look into that course of action. Gears take a while to cut, and the custom cutters for them (if needed) are big time expensive.
>> 
>> Bob
>> 
>> On Mar 24, 2014, at 8:13 PM, Brad Latta<bl_6000 at yahoo.com.au>  wrote:
>> 
>>> I'm looking for a custom made miniature worm drive manufacturer to replace a faulty nylon one. The worm motor has a 2mm shaft&  the output gear is on a 3mm shaft. The ratio is 10:1. Anyone know who can make this? , I have photos and dimensions.
>>>                                                                                                                                                                              Thanks, Brad
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