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your going to have to be careful with your design.... my bulkheads are 20mm Alumec89, there not going anywhere :P Also the bearings im using are taper bearings rated to 18,000rpm...not cheapo ones.
With all scorpions the numbers dirrectly after the letters corrispond to the motors diamater... also... the bigger the motor, the more power it has generally... the data sheets for the motors are on the scorpion power site.
Sorry, forgive me for being thick but where are the data sheets on the website, I can only find the dimensions at the bottom of each motor page, and there doesn't seem to be anything in downloads
http://www.scorpionsystem.com/catalog/m ... 890-12N8P/
scroll down..same for all there motors...all the info you should need.
So there is no start up torque figures or acceleration graphs? We just have to guess our pulley ratios and disc/drum weights... I thought it would be more accurate than that but its obviously worked for everyone else.
Are these suitable bearings for the drum? http://uk.rs-online.com/web/p/roller-bearings/0514120/
And these as part of the tensioning system? http://uk.rs-online.com/web/p/roller-bearings/0513868/
I am looking at their oiled speeds and their dynamic loading numbers
edit: sorry for all the questions
There ok, but a 12mm shaft is a bit small...id go for 17mm minimum..
im using these (RS Number 506-236) as i wanted something to take exstreme loading- for instance if NST hits it side on....verticles are weak to a good horizontal, with one hit on 360 i hit a verticle once, ruined his 10mm solid aluminium bulkheads and bent his 12mm thick hardox disc, bent the axle and smashed his disc motor...totaled his disc setup due to the weakness in his bulkheads....which apeared strong enough.
Because of this ive gone for a small diamater (less leverage to smash the bearings/bulkheads) a thick shaft (20mm solid stainless) and beefy bulkheads (20mm solid alumec) my bearings will be compressed up to the bulkheads, so the drum and bearings will be a perfect fit in the chassis....
If you plan on using that honey comb ali for your bulkheads id strongly reccomend otherwise.
Will and jamie seem to do well with HDPE bulkheads as they flex quite well.
We were going to double it up to 26mm thick with 2mm ti on the outside, and then glue in an Alu insert to sit the bearing in but your method will be much more reliable. We might test the cellite bulkheads in a drum beetle but we are now going to go with the tried and tested methods
eugh, i typed out a long post about aluminium honeycomb but my net screwed up when i submitted it. Can't be bothered typing it all again. To summarise, it can't be used to directly insert bearings into however is very usable. If you want info on the best ways to use it, give me a shout.
Ed's done a great job of cncing my bulkheads so far at work;
Skimming down the alumec 89 to exactly 20mm;
http://i685.photobucket.com/albums/v...s/a4cd5731.jpg
bulkheads and back bolted up;
http://i685.photobucket.com/albums/v...s/d836dc90.jpg
Just needs a square hole in each for the motor gearbox to sit in, 2 slots in each and a pocket for the drum axle to sit in, then there done... might make up the devider plates in the chassis this week some time.
Aww Dave, you should've told me you were gonna rebuild Drumroll in ali for me :wink:
Just kidding, it's looking great. I'm really liking the increase in drumbot production at the moment, gives me motivation to keep Drumroll running well and improving any areas that need it.
In-runners seem to be popular with the US drumbots and worked well in Galactus so I'm sure it'll pack a punch. Timing pulley looks weird without the teeth but hey, it works... :)