White Paper Discuss: Nothing But Dewalts

[Steve P]

If I buy the 12 Volt Dewalt Drill, the DC980KA, do I have all the parts I need to make the CIM / Dewalt tranny? I think I do except they only give you one of the screw you need two of? I really need help on this quick, thanks.

[Joe Johnson]

Originally Posted by Steve P

If I buy the 12 Volt Dewalt Drill, the DC980KA, do I have all the parts I need to make the CIM / Dewalt tranny? I think I do except they only give you one of the screw you need two of? I really need help on this quick, thanks.

A complete drill will have all the parts you need for a Chiaphua / Dewalt, including screws.

Joe J.

[Joe P]

Originally Posted by Steve P

If I buy the 12 Volt Dewalt Drill, the DC980KA, do I have all the parts I need to make the CIM / Dewalt tranny? I think I do except they only give you one of the screw you need two of? I really need help on this quick, thanks.

Steve,
Part 605256-01, in the BOM should be 1 not 2, the reverse threaded screw that goes in the end of the 1/2in.- 20 output shaft. I still need to do a revision to this paper.

Joe P

[Steve P]

Hey guys thanks a lot, We should be getting one soon to see if we want to use them this year. Ill let you know how it turns out.

[Steve P]

Another question, do the 12 voilt, 14.4 volt, and 18 volt drills with the 3 speed all have the needed parts and are basically the same? Was wondering if I needed a specific volt drill or if they all will do.

[Joe Johnson]

Originally Posted by Steve P

Another question, do the 12 voilt, 14.4 volt, and 18 volt drills with the 3 speed all have the needed parts and are basically the same? Was wondering if I needed a specific volt drill or if they all will do.

As far as we are concerned the 12, 14.4 and 18V XRP drills are the same. The motor is different and there may be some differences in the electronics and/or how the battery plugs into the clamshell, but all the parts that matter are the SAME part number.

FYI, the Hammer Drill is slightly different I THINK that it would be possible to change some of the dimensions and make it work, but I have not actually done it.

Joe J.

[Stu Bloom]

Originally Posted by Steve P

Another question, do the 12 voilt, 14.4 volt, and 18 volt drills with the 3 speed all have the needed parts and are basically the same? Was wondering if I needed a specific volt drill or if they all will do.

Check my spreadsheet (right click -> save as) attached to this post. Drill model numbers that have the correct parts are:
12V XRP - Model DC980KA
14.4V XRP - Model DC983KA
18V XRP - Model DC987KA

Good Luck!!

[ctorloey]

So I was wondering if the Dewalts transmission worked good for all of you how have it made and running it on the robot? My team started making our first one, we arn't done yet and I was wondering if they help out or did you all thing it was more of a waste of time.

[Kyle A]

My team used the Dewalts last year and they worked very well for us, we had some problems with shifting at our first event,but after we fixed the problem they worked wonders. It was nice to be able to go fast, to score and get away from defensive robots, and at the same time shift to be able to push back if we had to. We also used the low gear to climb up a ramp the one time we had to. I would say they are are not a waste of time, but it also depends on the game that is being played, if 3 speeds are not needed in the game then it may possibly be a waste of time, but they are a nice transmission to use, especially over the bane bots from last year.

[Mike Martus]

We have used the dewalts from the very moment Dr. Joe invented them.

Some comments:

To get the press fit correct you MUST wire EDM to exacting size.
We use a fixture to press on to the shaft of the motor for correct alignment and distance.
We created a fixture to control the sizes of the housings (we do no sand as per instructions) using a mill.

We do run 4 cims with 4 shifters that are in coordination....no issues

I believe the NBD System is still one of the easiest, lowest cost, reliable drive transmissions that all teams can make.

We have yet to have a transmission failure.

[Andrew Blair]

Originally Posted by Mike Martus

We have used the dewalts from the very moment Dr. Joe invented them.

Some comments:

To get the press fit correct you MUST wire EDM to exacting size.
We use a fixture to press on to the shaft of the motor for correct alignment and distance.
We created a fixture to control the sizes of the housings (we do no sand as per instructions) using a mill.

We do run 4 cims with 4 shifters that are in coordination....no issues

I believe the NBD System is still one of the easiest, lowest cost, reliable drive transmissions that all teams can make.

We have yet to have a transmission failure.

I'd like to echo everything Dr. Joe said, especially about the EDM, and the fixtures.

Carbide will not work well to machine the sun gears. They are some ridiculously hard powdered metal. If you want to use these transmissions, you really must find someone to EDM them for you. It's quick, pretty simple, and most shops will be happy to do it for you.

There are two distinct variables that affect the CIM mate to the gearbox. One is the final length on the plastic housing, and the other is the press fit of the sun onto the CIM. Both of these will need to be quite accurate, or else you'll need to modify one or the other. We ended up doing this, but it's really not a good idea.

If you do choose to shift (not at all necessary, these gearboxes are amazing just locked into second gear!), you'll need to make absolutely certain that your shift ring slips well, and there are no binds. You'll also need a longer horn to get adequate torque- I recommend buying a new, longer one, and not relying on the adjustable ones that come with the servos. They slip.

Ultimately, the Dewalts, as Dr. Joe has said, really are the best imaginable gearbox that can be adopted for FIRST. They mate to everything, they're super light, easy to mount, have awesome three speed capability built in, and are tough as nails, even if you abuse them. However, the challenge is in making them. If you are willing to invest the planning time and schedule dedication to get everything fabricated and ordered for them, they will give you few hassles, and really make the design of the rest of the robot easier.

However, if you hack your way through the process, you'll wind up with a hacked piece of junk. Imagine that... If you put the proper effort into the Dewalts, they will return it a hundred-fold.

[Aren_Hill]

id like to beg the differ on the modification of the sun gears. my team (1625) had 4 dewalts on the drive of this years robot. and all of the sun gears were modified on a manual lathe with a combination of HSS end mill and 1 carbide ream. and they never had any problems the whole season.

[AdamHeard]

Originally Posted by Mike Martus

We have used the dewalts from the very moment Dr. Joe invented them.

Some comments:

To get the press fit correct you MUST wire EDM to exacting size.
We use a fixture to press on to the shaft of the motor for correct alignment and distance.
We created a fixture to control the sizes of the housings (we do no sand as per instructions) using a mill.

We do run 4 cims with 4 shifters that are in coordination....no issues

I believe the NBD System is still one of the easiest, lowest cost, reliable drive transmissions that all teams can make.

We have yet to have a transmission failure.

Could we get drawings of these fixtures? that would be an awesome addition to the whitepaper.

[Mike Martus]

We have no drawings, but I will have students take some digital pictures of all the fixtures we use and upload them to the cd media section. I will post here when the students have done them.

The fixtures really help.

[ctorloey]

I was wondering how the dewalts worked on the programing side of things? having the robots switch speeds during the matches, was that complicated for the programmers to solve? Or was it easy to program.