modifying parts?

[firstborn]

Can you take the spring off of the BIG CIM motor? Would this be considered "modifying" parts?

[Veselin Kolev]

Originally Posted by firstborn

Can you take the spring off of the BIG CIM motor? Would this be considered "modifying" parts?

As it simply unscrews, yes you can. Just like you can take the transmission off the FP motor and the globe motor. You can also cut the output shafts, or make your own keyslots in the CIM shafts. The main thing you can't do is rewind the motors.

[r_towle]

Originally Posted by Veselin Kolev

As it simply unscrews, yes you can. Just like you can take the transmission off the FP motor and the globe motor. You can also cut the output shafts, or make your own keyslots in the CIM shafts. The main thing you can't do is rewind the motors.

Could you drill mounting hole in the new cim motor to enable use in the transmission?
I am talking about removing the spring, and pulley etc then machining the end plate so you can mount it.
Rich

[dez250]

Please take these answers with a grain of salt. Unless it is posted in the 2006 FRC manual or posted directly from FIRST, all answers are unofficial.

[Joe Ross]

Originally Posted by dez250

Please take these answers with a grain of salt. Unless it is posted in the 2006 FRC manual or posted directly from FIRST, all answers are unofficial.

And the official answer is that it is allowed: http://forums.usfirst.org/showthread.php?t=311

[Richard Wallace]

Originally Posted by Joe Ross

And the official answer is that it is allowed: http://forums.usfirst.org/showthread.php?t=311

The Q & A link above allows drilling and tapping holes to facilitate mounting.

Originally Posted by dmok

Just be careful machining the motor end plates: there's a lip cast into the top one to hold the shaft bearing, and machining the top totally flat removes this lip. We found out the hard way.

Machining the endplate as dmok describes above clearly modified the integral mechanical system of the motor (the bearing was no longer retained) so I'd still say it violated the intent of <R36>.

[dmok]

Originally Posted by r_towle

Could you drill mounting hole in the new cim motor to enable use in the transmission?
I am talking about removing the spring, and pulley etc then machining the end plate so you can mount it.
Rich

We needed an automotive puller to break the end pulley (it was locktite'd or something). Just be careful machining the motor end plates: there's a lip cast into the top one to hold the shaft bearing, and machining the top totally flat removes this lip. We found out the hard way.

[greencactus3]

Originally Posted by dmok

We needed an automotive puller to break the end pulley (it was locktite'd or something). Just be careful machining the motor end plates: there's a lip cast into the top one to hold the shaft bearing, and machining the top totally flat removes this lip. We found out the hard way.

already need a new one? jeez lol. well to our benefit i guess. wanna post up pics of the insides then?

[Al Skierkiewicz]

Originally Posted by dmok

We needed an automotive puller to break the end pulley (it was locktite'd or something). Just be careful machining the motor end plates: there's a lip cast into the top one to hold the shaft bearing, and machining the top totally flat removes this lip. We found out the hard way.

Dmok,
You may not modify the motors provided in the kit by machining the end plates. If you want to use the large chalupa motor on the kit transmission, AndyMark makes an adapter kit. See this
http://www.andymark.biz/kit-tran-upgd.htm

See also...

<R36> So that every robot’s maximum power level is the same, the motors in the kit may not be modified in any
way, except as follows:
• The mounting brackets and/or output shaft/interface of the motors may be modified to facilitate the
physical connection of the motor to the robot and actuated part.
• The gearboxes for the Fisher-Price, and Globe motors are not considered “integral” and may be separated
from the motors. FIRST will not provide replacements for parts that fail due to modification.
• The electrical input leads on the motors may be trimmed to length as necessary.
The intent is to allow teams to modify mounting tabs and the like, not to gain a weight reduction by
potentially compromising the structural integrity of any motor. The integral mechanical and electrical system
of the motor is not to be modified.

[Richard Wallace]

Originally Posted by Al Skierkiewicz

Dmok,
You may not modify the motors provided in the kit by machining the end plates. ...
See also...

<R36> So that every robot’s maximum power level is the same, the motors in the kit may not be modified in any
way, except as follows:
• The mounting brackets and/or output shaft/interface of the motors may be modified to facilitate the
physical connection of the motor to the robot and actuated part.

Al, While I generally agree that using the AndyMark (or some other) adapter should be the preferred method of mounting the big CIM to the kit gearbox, I cannot follow your reasoning above. It appears to me that the first exception to <R36> which you quoted above specifically permits modifying (e.g., by machining) motor end plates. How did you conclude the opposite?

[Al Skierkiewicz]

Richard,
In looking at the inspection guidelines from 2005 which are consistent with the 2006 rulebook, the end plate of the Chalupa motor(s) is not a mounting bracket, it is an integral part of the motor, unlike the van door and window motors which have obvious mounting brackets. Those motors have unusual mounting flanges with an odd position for mounting holes. It had been ruled in the past that those mounting brackets could be modified. In the case of the Chalupa in particular, the magnetic structure may be compromised by changes in the motor frame.

A red flag for me comes in response to the end of R36 should the intended modification lighten the motor or cause a problem with structural integrity.

As always, it is best to use the Q&A for official answers. I do not speak for FIRST.

[Richard Wallace]

Originally Posted by Al Skierkiewicz

... the end plate of the Chalupa motor(s) is not a mounting bracket, it is an integral part of the motor, unlike the van door and window motors which have obvious mounting brackets. Those motors have unusual mounting flanges with an odd position for mounting holes. It had been ruled in the past that those mounting brackets could be modified. In the case of the Chalupa in particular, the magnetic structure may be compromised by changes in the motor frame.

A red flag for me comes in response to the end of R36 should the intended modification lighten the motor or cause a problem with structural integrity.

As always, it is best to use the Q&A for official answers. I do not speak for FIRST.

Al,
The 2005 FRC Robot Inspection Checklist Manual v. 1.2 contains some unclear guidance on p. 77 under the heading Motor Modifications, saying in one place that it is OK to modify housings and in another place that it is not OK to modify integral mechanical parts. I agree with your interpretation that in the case of the big CIM motor the endplates are integral mechanical parts, not merely elements of a housing. While machining the endplates would not compromise the magnetic structure (since the endplate material is not ferromagnetic), such machining could potentially cause a problem with structural integrity and therefore violate one of the main intents of <R36>.

I also agree with your overall conclusion that neither this thread nor any other discussion on CD can be considered authoritative; only FIRST Q & A can provide an official resolution to a question of rules interpretation. I hope that someone with an interest in this topic will submit a question there so that we get clarification of what modifications are and are not allowed for mounting the big CIM.

And let me repeat, the preferred method should be to use the AndyMark (or some other) adapter kit. This will facilitate easy replacement of a motor at an event if necessary.

[Al Skierkiewicz]

Richard,
That was one of the references I turned to when composing my previous post. It also reminded me of some of the conference call discussions on this subject during inspector training.