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-   Driving Mechanisms: Rack/pinion, gears, screws, belts & chains (http://www.mechmate.com/forums/forumdisplay.php?f=24)
-   -   Rack and Pinion Suppliers: In the USA (http://www.mechmate.com/forums/showthread.php?t=313)

fabrica Sat 04 November 2006 07:57

Rack and Pinion Suppliers: In the USA
 
Can some one give me details of a U.S.A. manufacturer/Stockist of good quality Racks & Pinions.

Gerald_D Sat 04 November 2006 08:22

For Gear Pinions in the USA, look to Boston Gear 0.5" gear face width, 20 pitch, about 20 - 30 tooth pinions (depends on motor choice), 20 degree pressure angle <-- the three 20's are coincidental, they mean different things Metric guys will look for module 1, 20 degree pressure angle and about 25 teeth, face width 15mm and 15mm square rack.

Vadeem gave us this link to save everybody in USA some time(page 38):
http://bostongear.com/pdf/catalogs/P...penGearing.pdf (5.3MB pdf)"

Dirk Hazeleger Sat 04 November 2006 23:04

Best place I've found Gear Rack in the US. About a third the cost of others
http://www.stdsteel.com/gear.htm
Dirk

Gerald_D Sat 04 November 2006 23:22

That's useful Dirk. I see they only do rack and not pinions. Just a note to tell everyone it is no problem to mix the suppliers of rack and pinion - as long as you specify pitch, pressure angle and width.

fabrica Sun 05 November 2006 00:41

I have gone through the Boston gear catalouge. As per your specs mentioned in anothe thread I assume I have found the correct pinoin and rack. For the Pinion the Catalogue page no is 30 and the item code is 46133. For the Rack the Cat page number is 35 and the item code is 12760 (6 foot lenth). If you have the time can you please conform this so that I do not make a expensive mistake.

Gerald_D Sun 05 November 2006 01:22

Fabrica, so you want me to make the expensive mistake for you? http://www.mechmate.com/Forum/clipart/wink.gif

Your selection looks 100%. You will need 4 pinions and enough rack for 2 x-rails, 1 y-rail and 1 z-rail.

Also see this paragraph on page 150:

http://www.mechmate.com/Forum/messages/12/1871.gif

You can decide later if you want to use them soft or hardened. The soft condition is okay for a few month's use. (You cannot buy them already hard - that is your own responsibility after boring out and cutting the threads)

fabrica Sun 05 November 2006 04:30

Understood thanks, I will have that hardening part in mind.

Mike Richards Sun 12 November 2006 17:45

McMaster-Carr supplies my spur gears. They also sell 6ft lengths of rack. Page 985 of their catalog shows the current price of 6ft 20-pitch rack at $40.60. 20-pitch 20-tooth, 25-tooth and 30-tooth gears are $13.02, $13.55 and $14.88 respectively.

Gerald_D Wed 15 November 2006 05:41

The minimum pinion teeth count should be about 20, so that the spring-loaded pinion rolls relatively smoothly on the rack. 20 tooth pinions with module 1.5 or DP 16 are starting to give lots of linear travel for small rotations. I would search further to find finer gears. But, in a pinch, they will work.

Gerald_D Wed 15 November 2006 21:50

14 degree was a popular face angle (the side of a rack tooth is flat and it leans at the face angle) with the inch guys. The metric world standardised at 20 degrees. Even the inch guys are swinging to 20 degrees now.

A 20 tooth pinion works against a rack with about 600 teeth. If the materials were equally hard, the rack will last 30 times longer than the pinion. For short racks, it might make sense to have hard racks/soft pinions, but racks are cheaper than pinions if you take number of teeth per dollar.

Gerald_D Thu 16 November 2006 02:29

Every router that I know of uses the plain, basic, unhardened steel racks. MechMate & ShopBot included. The correct name probably isn't "mild" steel - mild steel is typically un-hardenable with a carbon content less than 0.3%

Chiaravalli say they use C40 for racks and C45 for pinions - "medium carbon" steels.

DocTanner Fri 17 November 2006 15:00

As Dirk pointed out http://www.stdsteel.com/gear.htm is the most economical around. 4 - BF200011 20dp 20 degree 6' racks $23.20 each. Ordered on the 13th.Received the 24th. They don't take credit cards. Mailed check to them and still got quick delivery time.

Gerald_D Fri 17 November 2006 22:08

Seeing that stdsteel doesn't sell gear wheels to run on their racks, they should be able to give great advice on where to get economical pinions.

Herb Lichtenberg Thu 30 November 2006 08:56

What does the length of the rack need to be on the main table x-rail? Most suppliers only have racks 60-72" long. I'm beginning a build and putting together a list of supplies that I need to order. I'm completely new to all of this so I apologize if this is a dumb question.

After looking at your site for months, I've been inspired to build your machine. Not to mention I have good relations with friends in the CNC laser and milling machine areas. That helps!

Gerald_D Thu 30 November 2006 09:12

Hi Herb, drawing M2 10 110 W tells you how to join racks, and also tells you that the X-rack must be the length of your table top (X) plus 200mm [7.9"]. The 60-72" racks are pretty standard, but they can easily be joined. You use a 3rd piece of rack as a jig, or template.......

Having friends as suppliers is always useful! http://www.mechmate.com/Forum/clipart/happy.gif

vadeem Tue 05 December 2006 01:03

Quote:
I have gone through the Boston gear catalouge. As per your specs mentioned in anothe thread I assume I have found the correct pinoin and rack. For the Pinion the Catalogue page no is 30 and the item code is 46133. For the Rack the Cat page number is 35 and the item code is 12760 (6 foot lenth).
Someone asked me why the page #s were wrong. The pages fabrica quotes are the printed page #s at the bottom of the catalog, not the PDF page numbers in the Adobe box.

Just to make it easy on everybody...

Hugo Carradini Thu 22 February 2007 14:04

Gerald, sorry to bother but I am having problems with the pinion. I am buying Boston Gear (Rack L2020 6´) but I am confused with the pinion I was thinking in Boston Gear (pinion YA20) but I am not sure because it seems don't have screws to tigt up. ¿Can you please help me with the right pinion I should get from Boston Gear.
I appreciate your effort and and I am pleased to tell that I am buying all my stuff I am importing next monday.

reza forushani Thu 22 February 2007 14:24

Hugo

I ordered pinions twice by mistake. If you need it, I can send it to you. They don't the screw but you can ad that.

Hugo Carradini Thu 22 February 2007 15:41

Thanks reza. The only problem is that i have to send things to Miami and then from there I have a courier and they send it to me. Little complicate but things get lost when I have them send strait to me . ¿You buy the YA20 and fitted OK?
I guess I can make the treads to fit.
Thanks

reza forushani Thu 22 February 2007 16:06

Yes they fit perfect. I bought from Mcmaster but its is a Boston Gear, I will look up the model# and post it for you.

Gerald_D Thu 22 February 2007 21:59

Making the threads in the gear is easy. Finding good "grubscrews" in your country is maybe not so easy. Most grubscrews everywhere are normally okay, but some rare times we find soft grubscrews which are real junk. Make sure you can get good hard ones.

eloid Thu 01 March 2007 20:57

14 1/2° and 20° pressure angle spur gears and racks which is better and why?

Gerald_D Thu 01 March 2007 22:04

14.5 has less chance of jumping out, but more chance of breaking off. For a spring-loaded ride, the 20 runs smoother.

fabrica Sun 13 May 2007 20:21

Gerald, For my earlier mechmate I ordered the racks from boston Gear the order number was 12760.
Last week when my friend in U.S.A made a inquiry for another set of racks and they have said that they no longer carry this item in stock. What other options are availale for us. I would prefer to buy from U.S.A. Manufacturer so that I could get the whole lot shipped in one set.

Gerald_D Mon 14 May 2007 02:21

Part no. 12760 still appears in their catalogue (page 35). There is also a 4ft long version of that rack under part number 12758. If you read through this thread, there are quite a few other suppliers mentioned.

fabrica Mon 14 May 2007 04:38

Thanks Gerald, I will see weather 12758 is available with them.

sailfl Tue 27 November 2007 03:04

Gerald, once again, thanks for the good advise.

I am looking now for less expensive but of lasting quality racks. Is $102 / 6' rack the going price or is that high? Pinon - $22, sound reasonable.

Mike Nash Tue 27 November 2007 08:20

I purchased 4 each, P/N 200011 73" 20PA 20 Pitch Gear Racks for $24.80 each plus $20.00 for shipping in June 2007 from http://www.stdsteel.com/gr_stock.htm for a different project. They don't take credit cards though so I had to mail them a check.

For $33.62 plus $4.25 shipping, I bought a P/N 6847K22 1 foot long, 20 degree PA, 20 pitch, 1" pitch diameter spur gear rod from http://www.mcmaster.com to make the spur gears from on my 12x36 lathe. This was much cheaper than buying individual gears but requires time and a lathe. I will have need of at least 8 gears eventually for 2 different projects. I should be able to get 10 or 11 easily from this 12 inch blank. Plus I get to bore for a nice tight fit to reduce cyclic errors.

sailfl Wed 28 November 2007 06:54

I am amazed at the price difference between Boston Gear and Standard Steel price for the same rack.

I understand McMaster Carr carries Standard Steel racks. Does anyone have the Carr part number. I am not able to find the right rack using their online catalogue.

Thanks

gmessler Wed 28 November 2007 08:56

Hi Nils,

I believe this is the correct rack 5174T21 but the Standard Steel does have the best price.


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