Dewalt transmission problems?

Can anyone, who has used the Dewalt 3 speed tranny , tell me what shortcomings or issues you experienced? I am planning to use them this season, and would like to know what we may be in for.

there is a really good white paper that you can find here: http://www.chiefdelphi.com/forums/papers.php?s=&action=single&paperid=398

Here’s an evaluation paper, though it doesn’t cover *every *possible bad thing about the transmissions. We also are considering thses transmissions this year, so this thread is good in my book.

http://www.chiefdelphi.com/media/papers/2826

Short answer:

74 matches - ZERO problems

That’s with 4 wheel direct drive from CIM motor

I have read the white paper. It is very good information on building the tranny with the kop motors. I found the following posting thread, http://www.chiefdelphi.com/forums/showthread.php?t=37260 , it has some good info too. The last post from team 321 is interesting. They used two motors geared together driving one Dewalt tranny. I would like to get some more info from them, as well as get more input from other users.

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We used them last year with the CIM motors for our drivetrain - NO problems. We originally planned to use 4 CIM/DeWalt assemblies (one per wheel) but had to drop to two to make weight and still had plenty of power and speed. We have already ordered our XRP drills to cannibalize for this year’s bot (see my source info in this post).

You should make sure you understand how much power you need and can effectively use. IMHO two CIMs per tranny is overkill, as possibly evidenced by the post you referenced (“The transmission actually stripped the threads from the inside of the sprocket” ).

We did have some problems with the transmissions we made last year. We did not follow the NBD white-paper and had some problems. We ended up going through about 8 transmissions in 2 competitions. We ended up stripping out a few of the metal housings because of the changes we made. Since last year we have reworked the transmissions and we don’t seem to be having the same issues. If you read the white paper written by one of my students, http://www.chiefdelphi.com/media/papers/2826 you will better understand the problems we faced. If you look at the pictures he included in the white paper you can get a rough idea of our design. (& by we & our I mean their & their’s)

Our design worked well when not used for shifting because we could just clamp it down into place. The ones we have re-worked to Dr. Joe’s specs seem to be working much better.

** this is not an attempt to pirate this thread but…
We tested out some Andy-Marks this fall and they worked great. There is a HUGE difference in cost between the 2 … if done correctly the first time. But if you never screw up how will you know if something doesn’t work.

Amen to that!

last year we used it on our arm and we had no problems so

We followed this whitepaper to make some 3 speed DeWalt transmissions and they worked well for the price.

We did encounter one major problem however, during one match we completely lost the drive to one side of our robot. We brought it back to the pits to test it out, and it appeared to be working fine. During our next match though, our drive was still out on that side so we replaced the transmission.

We disected it when we got home and discovered that the tophat gear that attaches directly to the motor had slipped on the shaft and could be kept from turning in high torque situations. We were suspisious of this when we first made the transmissions, but they had a very high success rate and we trusted them to hold up nicely. We decided that it was a slight error in our machining and just left the robot as is for the next regional. We still had one more spare after all…

Then at the next regional, it happened again. We put in the last replacement and decided to try and make a quick reliable fix incase we broke another one. We keyed the plate that the tophat gear screws onto with a file and put a key on the motor. Then we stuck locktite on it and used 1388’s vice to press the gear back onto the motor shaft (thanks again 1388!).

We put the new transmission in before the finals and it held up beautifully. We shall see how it works at nationals.

We asembled a Dewalt with Fisher Price. We ruined two motors trying to press fit the gear on with it reamed to .1255 I’d go slightly bigger than that if I were you. Other than that, we had no problems, but it didn’t actually make it onto the robot due to weight.