I’ve got some spare times on my hands and I’m thinking up new ideas for my chassis. My dilemma is I am using two Harbor Freight motors and they have to be on opposite ends of the chassis, to drive the opposite sides. Would one pillow block be enough to hold the sprocket in place? I’ve got 6mm brackets. Thanks
Oh yeah, I’ve got AutoCAD 2007 at my disposal, so I might design some things 
Anyone?
I’m not sure, since I’ve never used those pillow blocks.
Perhaps Jim could chime in there.
Usually, though, it’s a good idea to go with two pillow blocks unless the pillow blocks being used have a strong enough axial load capability as well as very little axial wiggle.
That’s what my main concern would be. It’d make things a whole lot simpler if I could just run one block.
By the way…
Combat Bot buddies tell me, the best durabilities can be achieved by mounting the bearings on either side of the wheel itself.
If you’re rover is going to be taking any real abuse (i.e. not a strictly-house bot) I’d suggest going with that.
Having to spend twice the $ on two pillow blocks beats having to do it later after you ruin the first pilow block, stall out the motors and damage your speed controller and batteries.
As I’m sure you know from your RC experience, there’s more than enough unknowns that can go wrong in the system to be skimping on the parts where you can be sure of the durability.
But then… you know how I feel about overkill.
Yeah my expericence with a brushless RC18T was a rough one. Got pretty much top end electronics, then the diffs go, get the diffs, tires don’t hold up, etc etc. That was a $600+ dollar mistake 
That might be a tough one having bearings support both sides of the cogs. Looks like I’ll have to conjure up some new ideas!
Hey…
If you run out of them, take some pics and we all brainstorm.
f10.putfile.com/thumb/8/23816174698.jpg
Apparently my dial up connection doesn’t like a 7 megapixel picture
What would be a good motor controller for this? Don’t drill motors pull something like 40A? They’re the 18V model from Harbor Freight, but I’ll probably run lower. Maybe Lipo or just hack open the drill battery.
Yea, I’ve been told so.
Well, you can borrow and modify the OSMC design and perfboard/PCB the necessary controllers for a hundred or so.
Or you can buy the kits from them for a lot more.
I don’t know of any deals that come close enough to that to bother mentioning.
Hopefully someone else has got some controllers in mind.
I see where you’re running into the problem of double-blocking.
those shafts don’t look long enough to be able to.
I suppose if you’re real careful with your motor mounting, you should be ok with one.
What size are those shafts?
Do they have a threaded end?
There is a threaded part on the shaft and I’m pretty sure it’s about 9mm. Then there’s a left hand screw that screws into the end that is 5mm. That’s how the cogs are being held on right now. But I have a feeling once it moves under its own weight, the screws might loosen up. Thought about having a friend mill down the shaft from 9 to 6mm, but as you can see in the picture, I’m almost positive it would bring the cogs and tracks themselves too close to the frame 
Edit- It looks like there’d be less than 1/4" between the inside edge of the track and the frame if I had the shafts milled down. If I did get them milled, it would make it easier to mount the non driven cogs.
Jim do you think you could shed some light on my situation?
Um, I am still waiting for the 6mm pillow blocks. I had to go to another place for them because the old supplier upped the price so much. The new place is cheaper, but slower.
I would not recommend you try to use one pillow block to hold an axle like you are proposing. As Nick said the best way is to use one on both sides of the wheel (sprocket). However, I have already designed and ordered some new hubs that will allow the sprockets to be held between two panels (aluminum, lexan, or other) that are 1.5" apart. The hubs have 3mm shafts on either end for the ball bearings we use. The sprocket assembly is held (centered) inbetween the two panels. This will allow making a passive sprocket, but I still recommend idlers too. Hang on there, help is on the way. 
Hey Jim any updates on this? Thanks!
Edit-My order has been placed!
