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  #1  
Old Mon 29 June 2009, 08:58
Claudiu
Just call me: Claus #43
 
Arad
Romania
Rack and Pinion - understanding Diametral Pitch (DP) vs. module

Hi everybody

I ordered OM 7.2. I checked also MM Gear Resolution table but I couldnīt understand exactely.
Do I have to use for a OM 7.2 a 36 teeth pinion or can I also use a 24.
What is the consequence?

Thx
Claudiu
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  #2  
Old Mon 29 June 2009, 09:33
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Claudiu,
Are you using USA style 20 pitch or Mod 1 or 2 rack.

Pinions in either case should allow for you to use anything between 20 - 36 teeth. The MM builders typically use a 30-35 tooth for the 7.2 geared motors.
Using the geared motors your really only affecting speed of the machine. Yes, you are affecting the torque value too, but the needed torque isn't drastically effected.

My recent couple of builds use 7.2 Geared motors with 30T pinions on 20 pitch rack.

Last edited by smreish; Mon 29 June 2009 at 09:35..
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  #3  
Old Mon 29 June 2009, 10:56
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Claus, if you want max speed with slightly lower cut quality, use 36 teeth module 1. If you want slightly lower speed and better cut quality, use 24 teeth module 1. The differences are not as big as they sound.
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  #4  
Old Mon 29 June 2009, 11:58
Claudiu
Just call me: Claus #43
 
Arad
Romania
Metric System

Sorry, no Pitch, metric !!!

So for the first try Iīm going Metric System with 35 teeth on a 15 mm rod.
Letīs see what happens.

What about using 35 teeth for the x and y, and a 20 for the z?
Any opinions?

Thx
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  #5  
Old Mon 29 June 2009, 12:00
Claudiu
Just call me: Claus #43
 
Arad
Romania
Module 1

Quote:
Originally Posted by Claudiu View Post
Sorry, no Pitch, metric !!!

So for the first try Iīm going Metric System with 35 teeth on a 15 mm rod.
Letīs see what happens.

What about using 35 teeth for the x and y, and a 20 for the z?
Any opinions?

Thx
Module 1, sorry Iīm new here, so sometimes I do not understand immediately...
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  #6  
Old Mon 29 June 2009, 12:15
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
20 teeth, module 1, is too small for a 15mm shaft. Check the dimensions yourself. It is okay to mix the gear pinion sizes. Actually, they are not expensive, you can buy some different sizes for experimenting.
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  #7  
Old Sat 22 August 2009, 09:37
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Gerald and All,
For Rack and pinion in metric system.
If I use rack at module1(15x15mm),what is the popular teeth of pinion gear?
If I use rack at module1.5(15x15mm or 17x17mm),what is the popular teeth of pinion gear?

Add Information,
I use stepping motor with gear reducer at 4:1 ratio transmission.( X and Y axis)
Driver timing pulley = 18 teeth
follower timing pulley = 72 teeth
XL belt.

Hope your help
Mongkol
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  #8  
Old Sat 22 August 2009, 09:54
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
If I use rack at module1(15x15mm),what is the popular teeth of pinion gear?
Somewhere between 24 and 36 teeth. 24 will be a bit smoother, 36 a bit faster in soft material. Doesn't make too much difference. Most go for the bigger & faster.

If I use rack at module1.5(15x15mm or 17x17mm),what is the popular teeth of pinion gear?
20 to 24 teeth. Not many people have used module 1.5
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  #9  
Old Sat 22 August 2009, 10:11
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Gerald,
Big Thanks for the informations.
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  #10  
Old Mon 02 November 2009, 07:48
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Puzzled with DP. What does it mean?

Dear All,
I choose the rack and pinion at module1.0 and the popular pressure angle at 20 degree. I am little puzzled with Diametral Pitch(DP). What does it mean?What is the effect if I choose the different DP at 16,20,24 or so on? Pls advise.
Pls have a look the example in attached link.
http://www.qtcgears.com/e-store/RFQ/...g_4-002_1.html
http://www.qtcgears.com/e-store/RFQ/...g_4-005_1.html

Mongkol
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  #11  
Old Mon 02 November 2009, 09:43
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
See: http://www.sdp-si.com/D190/HTML/D190T109.htm

Diametral Pitch = The number of teeth of a gear per inch of its pitch diameter (teeth per diameter)

Module = amount of pitch diameter per tooth, in millimeters (diameter per teeth)
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  #12  
Old Tue 03 November 2009, 21:26
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Gerald,
It helps me go to the right direction. Thanks for the information.

Ton
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  #13  
Old Fri 29 January 2010, 15:52
15mgtar
Just call me: 15mgtar
 
anaheim
United States of America
having a hard time understanding MOD

Was a separate thread, now moved in here . . .

Hi all,
What is the difference between mod 1 and mod 6 ( do mod 1 have a smaller and finer gear than mod 2)? the only spec I got is mod 1 = 15x15 and mod 2 = 60x60 it doesn't make any sense for me.
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  #14  
Old Fri 29 January 2010, 19:50
KenC
Just call me: Ken
 
Klang
Malaysia
Yes, mod 1 is finer then mod 2, & there are mod 0.5 as well. bigger the number larger the gear pitch. wiki spur gear will go a long way.
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  #15  
Old Fri 29 January 2010, 22:34
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Please read before starting a new thread!

Rack and Pinion - understanding Diametral Pitch (DP) vs. module <-----this thread
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  #16  
Old Sat 30 January 2010, 01:42
15mgtar
Just call me: 15mgtar
 
anaheim
United States of America
Yes I did read the posting but really having a hard time understanding.
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  #17  
Old Sat 30 January 2010, 04:02
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Quote:
Originally Posted by 15mgtar View Post
. . . . the only spec I got is mod 1 = 15x15 and mod 2 = 60x60 it doesn't make any sense for me.
A typical mod 1 rack is a square bar of steel 15 x 15mm. A typical mod 6 rack is a huge square bar of steel 60 x 60mm.

Does this help?
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  #18  
Old Sat 30 January 2010, 05:52
15mgtar
Just call me: 15mgtar
 
anaheim
United States of America
yes I know that mod 1 is 15x15 and mod 6 is 60x60 but what I didn't know is the little mountains is finer and closer together on mod 1 compare to mod 6. Thanks I will stick to mod 1.
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  #19  
Old Wed 24 February 2010, 20:44
riesvantwisk
Just call me: Ries #46
 
Quito
Ecuador
Send a message via MSN to riesvantwisk Send a message via Skype™ to riesvantwisk
Here is also a nice explanation on the terms : like root, pitch and outside diameter. http://shopswarf.orconhosting.net.nz/spur.html

Ries
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  #20  
Old Wed 24 February 2010, 21:27
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Ries, that explanation ignores the metric world that uses the concept "module" to define the "coarseness" of the teeth.
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  #21  
Old Fri 16 April 2010, 04:05
Mongkol
Just call me: Ton
 
Bangkok
Thailand
The long rack

Gerald,
I have some question with the rack of module=1
Is it necessary to use the standard size of 15 x 15 mm for this?
My supplier can make it with one piece but he can not follow size 15 x 15 mm.
size 20x 20mm,Is it possible for ? Does it effect?

Mongkol
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  #22  
Old Fri 16 April 2010, 04:43
KenC
Just call me: Ken
 
Klang
Malaysia
Hi Ton,
There is a overhang clearance of 20~25mm between the edge of the angle rail to the main beam depending on how accurate you construct your table & rail alignment. This is the space where your rack will mount. As long as you can fit your rack in, the width of the rack doesn't matter, I recon the motor mount can accept 20mm high rack, if it doesn't, you can always extend the slot on the motor mount.
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  #23  
Old Fri 16 April 2010, 04:54
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
As Ken says, 20X20 could work, but you have to proceed very carefully. Also be careful at the gantry where you are maybe using 52mm wide tubes instead of 50mm wide tubes . . . . the y-car must still fit freely over the gantry and racks.
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  #24  
Old Sun 18 April 2010, 08:19
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Ken and Gerald,
Big Thanks for your guide.
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