PDA

View Full Version : Where to buy gears?



dbooksta
12-04-2017, 10:48 AM
I need a rack and spur gear train (pinion gear, reduction gear, drive gear, axles and mounts) for making manual minimal-slop position adjustments to a ~10kg load.

Where can I find such items at a reasonable price? (E.g., McMaster charges $100 just for a 12" steel rack!)

A.K. Boomer
12-04-2017, 10:51 AM
Don't know if they have what you need but check into "quality transmission components" and see if they do...

lakeside53
12-04-2017, 12:06 PM
Put your location in your profile. No point in asking for a source if we don't know where you are! Here I have a handful of different national and local bearing/transmission supply houses to choose from.

dbooksta
12-04-2017, 12:25 PM
Oops: Just added. I assumed best sources would be mail-order; didn't occur to me there might be brick-and-mortar sources for this sort of thing. I don't even know what category of supply this falls into? "Heavy hobby robotics?"

The Artful Bodger
12-04-2017, 12:40 PM
Sometimes you just have to look around and re-purpose something. For example what you describe could be the quill feed of a drill press.

dbooksta
12-04-2017, 12:47 PM
Don't know if they have what you need but check into "quality transmission components" and see if they do...

It appears they do, but holy smokes: just a single a rack segment is hundreds of dollars! I can't afford to begin to play if that's the cost of entry!

dbooksta
12-04-2017, 12:56 PM
Sometimes you just have to look around and re-purpose something. For example what you describe could be the quill feed of a drill press.

Yeah, I was thinking back to the good old days when I could pick up daisy-wheel printers that had linear control assemblies weighing 20-30 pounds!

But since I designed this gear assembly I feel like I'm missing something: I can specify almost any electronic part and have it in a day at a good price from Digikey et. al., or in a few weeks at a better price from China. When I can't find bar stock or machine bits locally I can often get what I need in two days at a good price from Amazon.

Actually, the gears don't seem too outrageous from sdp-si.com. I don't understand why racks are commanding such a premium.

Toolguy
12-04-2017, 12:57 PM
Amazon and eBay can sometimes be affordable sources for a variety of metalworking supplies.

elf
12-04-2017, 12:59 PM
Buy a 3d printer and you can make many gears much cheaper.

Glug
12-04-2017, 01:39 PM
Yeah, I was thinking back to the good old days when I could pick up daisy-wheel printers that had linear control assemblies weighing 20-30 pounds!


I tore a few of those down recently. The heavy shafts were spectacular. But the motion was controlled via cable and servo, not gears. Have you considered that approach? It seems to offer many advantages.

The Artful Bodger
12-04-2017, 01:42 PM
When I find myself stumped for the lack of something or other I tend to put the project aside until either the required parts come to hand or I get a flash of inspiration (which usually comes in the middle of the night).

Your requirement is for a rack, well a rack of sorts can be made with a length of roller chain but that may not be precise or slop free however a feed screw is something you can make in the lathe or use all thread if necessary.

gaston
12-04-2017, 06:06 PM
you can have what you want made here http://www.mooregear.com/gearracks.html or here http://www.rushgears.com/gear-types/rack
also here http://www.sdp-si.com/products/Gears/Index.php or try a internet search for "gears"

brian Rupnow
12-04-2017, 07:07 PM
McMaster Carr has a selection of small racks.

lugnut
12-04-2017, 07:30 PM
try https://shop.sdp-si.com/catalog/?cid=p590

true temper
12-04-2017, 08:09 PM
I have some new large rack + pinions, larger than an arbor press. Might be too big.

754
12-05-2017, 12:24 AM
Gears over about 100teeth are same profile as a rack.
So the easy forehead smacking solution......
Go to a scrapyard or wrecker, get a ring gear on a flywheel. And knock it off., then straighten a section long enough to use.
Now buy a pinion to match.
Not sure how much toothform will change when you straighten it.

754
12-05-2017, 12:31 AM
Jyst for kicks I searched 14 dp rack.. on ebay.
500 mm long unused one sold in the UK for 40.00 plus 16 shipping.
I have bought them from Browning before..

Search Boston gear rack on ebay, there is some brass 1 footers for 16 bucks, and many steel ones as low as 50 bux.

EVguru
12-05-2017, 04:52 AM
1.5 Mod, 500mm long, 17mm wide, less than 30

https://www.bearingsrus.co.uk/gears-racks/racks/sr15-17-5

tom_d
12-05-2017, 05:16 PM
Would the rack off an old South Bend or Atlas lathe be too big?

A.K. Boomer
12-05-2017, 07:37 PM
Go to a scrapyard or wrecker, get a ring gear on a flywheel. And knock it off., then straighten a section long enough to use.
Now buy a pinion to match.
Not sure how much toothform will change when you straighten it.

yeah but sorry to inform you --- there's not a pinon on the planet that could be a match, because you just created a "mate-less rack" simply by means of erroneous geometry....

754
12-05-2017, 07:57 PM
I suspect that for what he is doing, it may work.

john hobdeclipe
12-05-2017, 08:05 PM
I need a rack and spur gear train (pinion gear, reduction gear, drive gear, axles and mounts) for making manual minimal-slop position adjustments to a ~10kg load.

Where can I find such items at a reasonable price? (E.g., McMaster charges $100 just for a 12" steel rack!)


Can you give us some idea of the dimensions you have in mind? length, pitch, number of teeth, etc.?

A.K. Boomer
12-05-2017, 08:07 PM
Don't think so - it's one stage away from taking an external gear and trying to warp it around to make an internal --- there would be no room for the pinon gear teeth as the internals teeth would be touching each other,,,

trying to straighten an external round gear would leave you with slivers left for the pinon and they would break off when you tried to engage and disengage them due to geometric interference

elf
12-05-2017, 09:55 PM
I thought this was HSM not BuyBuyBuy:p
https://www.youtube.com/watch?v=ma6kdIHwrFI

dbooksta
12-05-2017, 10:54 PM
Can you give us some idea of the dimensions you have in mind? length, pitch, number of teeth, etc.?

I don't need more than 250mm length for the rack. I don't have any parts for the train yet so I'm not committed to pitch, PA, or any other specs. I just want them all to mate with minimal lash. I was hoping this would be the sort of thing that from the right source would be cheap, fast, easy, and let me get on with the project....

Glug
12-06-2017, 10:53 AM
Would the rack off an old South Bend or Atlas lathe be too big?

He said minimal lash. That'd fit more like Succotash.

mikem
12-06-2017, 01:53 PM
Taking the rack out of south bend or atlas seems sacrilegious! Kinda like bumping off grandpa to give his heart to the grand kids!

lakeside53
12-06-2017, 02:10 PM
How about this one $25 shipped; from an Emco lathe. Apron drive gear will be std module.


https://www.ebay.com/itm/Emco-Maximat-7-Long-Bed-Lathe-Rack-Mounting-Bolts-1123M7/391334127891?hash=item5b1d54e913:g:DyoAAOSwnipWX4T p

or

https://www.ebay.com/itm/Emco-Maximat-Super-11-Lathe-Rack-Mounting-Bolts-0601/391829141535?hash=item5b3ad6381f:g:KpsAAOSw~rpZVoG J


The gear etc if you need it (check size)

https://www.ebay.com/itm/Emco-Maximat-Standard-Lathe-Apron-Rack-Handwheel-Rack-Gear-Assy-0615/391853020676?hash=item5b3c429604:g:32kAAOSwAH1Zf1f F


Maybe even better: https://www.ebay.com/itm/Rack-1000mm-39-20T-Pinion-Gear-Module-1-5-CNC-KIT-Router-Plasma-Laser-lathe/162741890713?hash=item25e42c2e99:g:dwAAAOSwCU1YuGw M