making a gear segment from a drawing from long, long ago 2

[Tmoose]

A customer needs a new segment gear for a device designed in the 30s and 40s, and built in the 1970s.

Attached is an image showing the OEM drawings for the gear and worm.

A local shop said could make the gear if they had a step or dxf file of the parts.

Is it possible a "real" gear shop be able to work with the gear descriptions/dimensions directly?

thanks,

Dan T

 

[tbuelna]

I can only see the worm drawing. But this part is still commercially available from Boston Gear.

http://www.bostongear.com/pdf/upload/lit/P-1482-BG_pg074-086.pdf

 

[gearcutter]

It depends.
First thing to work out is if you're working with a throated gear or a spur/helical gear.

 

[Tmoose]

Sorry, that was the wrong image. This one shows the gear and the worm.

 

[Tmoose]

And this is the sophisticated mechanism it is used in. It is used to adjust cold air in a stoker boiler a few times per decade.

 

[Tmoose]

Looks like Boston Gear stocks some mating gears, but not with a 7" PD.

 

[Tmoose]

And the shaft bracket center-to-center is 1/16 " greater than the 4.25 C-C the pitch diameters would call for. That would provide a bunch of backlash and tip clearance and etc, , I suspect, so binding even with the most basic gear would be unlikely

 

[gearcutter]

You presented us with this same problem several years ago -

http://www.eng-tips.com/viewthread.cfm?qid=371768

 

[Tmoose]

yep. very similar, but a Different part. Did Google squeal on me?

I think it may be the same shop this time, because I think I heard 3rd hand that they thought they'd made one (somehow) for us before, but realized this one is different, so are looking for cad info.

 

[gearcutter]

Did Google squeal on me?

No, I just happened to recognise the gear data............which appears to be exactly the same as all the info we gave you in the previous thread.

 

[gearcutter]

In answer to your original question; yes, a gear shop will be able to make a set for you based on the info you've provided.

 

[Tmoose]

Thanks gearcutter. I just reminded purchasing we had the same gear segment made last year, presumably successfully.

I'm sorry I did not check deeper. The reported 3rd hand story that they thought they'd made a segment (somehow) for us before, but realized this one is different, must have a different interpretation than the one I assumed.

 

[mfgenggear]

agree with Gearcutter, shop can make it. the worm is easy, thread cut , thread grind or hob., the worm gear requires a worm to be used as a master to set the correct pattern and center distance. and a hob (based on the worm) will cut it.