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Unread 30-01-2011, 13:20
de_ de_ is offline
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Dewalt 3 speed gear ratios ?

Anyone happen to know what the gear ratios are on the typical Dewalt 3 speed drills ? If you happen to know specifically for a DC940, all the better but anything would be useful.
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Unread 30-01-2011, 13:36
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Smile Re: Dewalt 3 speed gear ratios ?

do a search on google for the DeWalt drill, and the speed specs will be listed. We have done DeWalt/CIM drives, and the difference between 2nd and 3rd wasn't very much. The 940 is a little better, but IMO is not needed.
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Unread 30-01-2011, 13:49
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Re: Dewalt 3 speed gear ratios ?

Start with the "Nothing But Dewalts" whitepaper.
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Unread 30-01-2011, 13:49
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Re: Dewalt 3 speed gear ratios ?

12, 16 and 48:1 if I recall correctly.

If building for a CIM you lose one 4:1 stage, leaving you 3,4 and 12:1.
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Unread 30-01-2011, 14:25
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Re: Dewalt 3 speed gear ratios ?

Thanks guys.

White paper drill is 47:1, 15:1, 12:1. Sorry I had forgot about that from years ago.

DC940 is definitely different as its pinion gear is different from the first planetary gear (unlike the drill in the white paper). But thats close enough for now. If I remember all three planetary sets are identical though.

I have no idea where on the internet they would list internal gear ratios of dewalts unless the dewalt parts lists show it which is not too likely as they would list just the gear box, not the 3 planetary sets in the gearbox. If anyone knows otherwise, let me know.
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Unread 30-01-2011, 15:18
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Smile Re: Dewalt 3 speed gear ratios ?

Quote:
Originally Posted by de_ View Post
Anyone happen to know what the gear ratios are on the typical Dewalt 3 speed drills ? If you happen to know specifically for a DC940, all the better but anything would be useful.
The drill lists the output speeds as 500,1200 and 2000. Ratios would be---
1:2.4:4, quite a bit different than the NBD white paper. Output speed and torque can then be calculated based on the motor you choose to mount.
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Unread 30-01-2011, 15:46
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Re: Dewalt 3 speed gear ratios ?

The following website sells the Dewault gearboxes and has unofficial specifications listed. I am not sure how accurate they are, but it might be worth looking at.

http://www.robotmarketplace.com/prod...walt_main.html
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Unread 30-01-2011, 16:23
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Re: Dewalt 3 speed gear ratios ?

We are using the Dc940ka gearbox with the FP motor. An unofficial source estimates the no load rpm of the dewalt motor to be about 20,000 rpm (about same as FP motor fyi), so estimating with the posted dewalt specs (2000, 1450, 450) I am guessing the gear reductions are about 1:10, 1:14, 1:44.5. These are pretty close to the nothing but dewalt specs. I am not certain of my calculation so I am ordering a few different size sprockets in case that I am wrong.
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Unread 30-01-2011, 16:31
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Re: Dewalt 3 speed gear ratios ?

I am pretty sure the exact 3 speed transmission and motor for the DC940 is listed on the robotwarehouse website. Now that I remember, I never took the transmission completely apart a year ago because I was afraid I couldn't figure out how to put it back together. Based on the overall ratios, the 3 planetary gear sets must each have different ratios.
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