pic: 499_Toltech_drivetrain

[Andrew Schuetze]

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[=Martin=Taylor=]

How exactly will the outer wheels be powered? Will you mount sprockets on the outer sides of the 80/20?

What kind of wheels will you use? Be warned about the preformance wheels... They are really expensive. $354 for six

Also, is it just me or does the 80/20 have three slots? Is it 1x2 or 1x3?

Nice job all around!

[Andrew Schuetze]

Originally Posted by Hachiban VIII

How exactly will the outer wheels be powered? Will you mount sprockets on the outer sides of the 80/20?

Yes, Al sprockets and #35 chain. What is missing is the stand-offs for mounting the bumpers.

Originally Posted by Hachiban VIII

What kind of wheels will you use? Be warned about the preformance wheels... They are really expensive. $354 for six

Will use AM / FIRST Wheels (On Sale before the season)

Originally Posted by Hachiban VIII

Also, is it just me or does the 80/20 have three slots? Is it 1x2 or 1x3?
It is 1530 light so it is 1.5 x 3. I found a CAD file of the extrusion on their website and extruded it to my design lenght.

Nice job all around!

thanks for the kudos, I am a bit worried as weight estimates come in at 45 pounds once chain & sprockets, Dual Cims, front and rear bumpers are added to this design. I like the adjustability of the 8020 but is sure adds on the pounds.

[Alex Cormier]

Originally Posted by Andrew Schuetze

Yes, Al sprockets and #35 chain. What is missing is the stand-offs for mounting the bumpers.

35 chain all the way around? Save some money and weight and go with 25, numerous team go with that without any issues if you tension it properly. I say 35 from transmission to one sprocket is good enough.

[=Martin=Taylor=]

Originally Posted by Andrew Schuetze

Yes, Al sprockets and #35 chain. What is missing is the stand-offs for mounting the bumpers.

thanks for the kudos, I am a bit worried as weight estimates come in at 45 pounds once chain & sprockets, Dual Cims, front and rear bumpers are added to this design. I like the adjustability of the 8020 but is sure adds on the pounds.

According to Inventor 1 foot of 8020-1020 is 0.9289 lbs. and 1 foot of 1x2 1/8" wall extrusion is 0.8077 lbs. In otherwords if you replaced your two 8020 rails with boxed extrusion you would save 0.748 lbs. Big deal.

#35 chain and sprockets are however a major source of weight. In a system with such easy tensioning there is no reason to not use #25. #35 should only be used when you don't want to have a tensioning system, or when (like on arms) there is a significant amount of twisting and the length of the chain has to be very long.

[Kevin Sevcik]

Originally Posted by Hachiban VIII

According to Inventor 1 foot of 8020-1020 is 0.9289 lbs. and 1 foot of 1x2 1/8" wall extrusion is 0.8077 lbs. In otherwords if you replaced your two 8020 rails with boxed extrusion you would save 0.748 lbs. Big deal.

Ah, but he's using 1530-Lite which, despite the name, weighs in at a whopping 2.012 lbs/ft. 1/8" wall 1.5x3" would run 1.339. I'm questioning the necessity of a 1530 profile here, unless you're planning for your robot to be rammed by a small car. I think 1020 with a cross brace or two would be plenty strong and would save you at least 6 lbs. If you're really hankering for that 3" height, then 1030 weighs in at 1.350 lbs/ft and would still save a few pounds.

[Cory]

Originally Posted by Kevin Sevcik

Ah, but he's using 1530-Lite which, despite the name, weighs in at a whopping 2.012 lbs/ft. 1/8" wall 1.5x3" would run 1.339. I'm questioning the necessity of a 1530 profile here, unless you're planning for your robot to be rammed by a small car. I think 1020 with a cross brace or two would be plenty strong and would save you at least 6 lbs. If you're really hankering for that 3" height, then 1030 weighs in at 1.350 lbs/ft and would still save a few pounds.

1010 works just fine on FRC robots, when used properly. Even with violent collisions.

[chris31]

Originally Posted by Cory

1010 works just fine on FRC robots, when used properly. Even with violent collisions.

If you use 1010 with the correct support braces and bumpers you wount have any problems with it.

[Andrew Schuetze]

1530 lite verses 1030 That is the trouble with ordering materials in advance due to the slow process at the school district. I had not checked the per foot weight of 1030 verses 1530 before ordering. The lite part not being lite threw me off. Seems odd that although it is a half-inch wider profile that light comes in heavier than the 1030. I suppose I could have gone with 1020. New at this design with 8020 thing, I wasn't certain how much structural strength would be lost by milling slots into the profile for the adjustable front/rear wheels. I now have two 8 foot lengths of the 1530 in the shop so either I don't go with this system this year and keep that around for some beefy vertical members or try and reduce weight on the other components. We still may not be able to go this route as I haven't heard back from the machine shop if they want to be an official team sponsor and help us with this project. Thanks for all the input.

[Kevin Sevcik]

Originally Posted by Andrew Schuetze

1530 lite verses 1030 That is the trouble with ordering materials in advance due to the slow process at the school district. I had not checked the per foot weight of 1030 verses 1530 before ordering. The lite part not being lite threw me off. Seems odd that although it is a half-inch wider profile that light comes in heavier than the 1030. I suppose I could have gone with 1020. New at this design with 8020 thing, I wasn't certain how much structural strength would be lost by milling slots into the profile for the adjustable front/rear wheels. I now have two 8 foot lengths of the 1530 in the shop so either I don't go with this system this year and keep that around for some beefy vertical members or try and reduce weight on the other components. We still may not be able to go this route as I haven't heard back from the machine shop if they want to be an official team sponsor and help us with this project. Thanks for all the input.

The strength lost would be negligible in even a 1020 profile, provided we're talking about something like a 1/2" x 1" slot or so. You could further reduce the effects if you could move the T-nuts from the top of your bracket to the sides so the side walls could carry a bit of the load. Realistically, though, in that profile, any strength you lose there isn't likely to hurt you. We've only used extruded aluminum once for a rather poorly executed robot that we let a sponsor have too much say in... But as I understand it, unless you have a few internal braces, your weak points will inevitably be the joints of your frame. A brace straight across the middle of your robot reduces the moment applied on the joins by 1/2.

[Andrew Schuetze]

4 Front / Rear dead axle saddle 0.28402 = 1.13608
2 1530 lite rail 33 inches 5.51536 = 11.03072
2 AndyMark Supershifter mount / saddle 0.38186 = 0.76372
2 AndyMark Supershifter 4.6 = 9.2
4 CIM motors 2.1 = 8.4
6 1" Angle Aluminum 26 /w 1.5 cut-outs 0.564 = 3.384
8 #25 Aluminum sprocket 30 tooth 0.125 = 1
12 #25 rollerchain per foot 0.09 = 1.08
6 AM FIRST wheels /w bearings 0.8 = 4.8
4 0.50 inch Aluminum shaft 4" 0.077 = 0.308

Total = 41.10252

This minus all the fasteners which include corner gussets for the 8020. I'll try and post an assembly drawing in a few (hours...days)

Comments welcome on weight reasonableness

[artdutra04]

Originally Posted by Andrew Schuetze

4 Front / Rear dead axle saddle 0.28402 = 1.13608
2 1530 lite rail 33 inches 5.51536 = 11.03072
2 AndyMark Supershifter mount / saddle 0.38186 = 0.76372
2 AndyMark Supershifter 4.6 = 9.2
4 CIM motors 2.1 = 8.4
6 1" Angle Aluminum 26 /w 1.5 cut-outs 0.564 = 3.384
8 #25 Aluminum sprocket 30 tooth 0.125 = 1
12 #25 rollerchain per foot 0.09 = 1.08
6 AM FIRST wheels /w bearings 0.8 = 4.8
4 0.50 inch Aluminum shaft 4" 0.077 = 0.308

Total = 41.10252

This minus all the fasteners which include corner gussets for the 8020. I'll try and post an assembly drawing in a few (hours...days)

Comments welcome on weight reasonableness

Are you using 1" aluminum angle to connect the two sides of the drive train? I personally wouldn't go any less than 1" box with 0.125" wall thickness (or equivalent 1010 extrusion).

Also, the 1530 Lite extrusion is overkill for practically everything in FIRST. 1020 extrusion should work just fine, and would save you a lot of weight (about 5 pounds!) in the process.