Beware - transmission output shaft is not 5/8"!

[Paul Copioli]

I figure I am the most qualified person in the FIRST community to talk about the transmission and why all choices were made. So here goes:

1. The 21 tooth sprockets supplied with the kit are supposed to mate with the transmission output shaft with no modifications. If this is not the case, then something is wrong and you should contact IFI or FIRST.

2. The transmission was designed as a result of FIRST listening to many people in the FIRST community regarding the importance of a functional drive train for all teams. FIRST, along with IFI and Dr. Flowers, asked JVN and I to help design a kit transmission and a kit gearbox for rookies and low budget teams to have a functioning, competitive drive base without any advanced machining capabilities.

3. 100% of my time was donated to FIRST for this activity which included concepting, design, detailed drawings, prototyping, and (important) the entire manual creation. If you read the manual, it mentions the 16mm output shaft in 10 different locations.

4. The only change made from last year to this year is the addition of mounting holes for the gear tooth sensor. IFI and FIRST may have chosen different suppliers than last year, but no design changes were made.

5. Metric is the World standard. There is no argument. When you get into industry you will probably deal with metric components. You must be what I call "metric bilingual". If I had my way, the entire transmission would be metric simply because I am an engineer that does all design work in metric. One of the terms I had for volunteering my time was being able to use metric where no significant cost to FIRST would be incurred.

6. For reason number 5 above, some things are still in the English system. The hex shafts are 3/8" and 3/4" for purely cost reasons. The fasteners are 1/4"-20 for commonality with the kit frame and for cost reasons.

7. Metric bearings outnumber English bearings by almost 2:1 in availability. My team bought a 16mm drill and reamer with a 5mm key way broach for less than $100. If your team can't afford that cost, then the kit transmission had you in mind ... use it as given to you.

8. The kit transmission will last you for multiple years. My team plans on re-using our gears on the competition bot this year just to prove this point.


The bottom line is that in week 1, at a regional with about 10 rookies (Finger Lakes) everyone was driving around and there were no spin in place robots to be found. This was a drastic improvement over the prior years. The kit transmission was (and still is) a huge success. If the 16mm shaft bothers you that much (it is 0.004" larger than 5/8"), then just machine your own transmission ... or keep quiet. I really have no more patience left for the complainers. Better yet, you do something; I mean really DO something; to help out FIRST and the rest of the FIRST community.

When you give more than you receive, then come talk to me about the kit transmission.

Sincerely,

Paul Copioli