Help with filament drive reels

Hey you guys! First post ever, first printer I've stepped up to building, too. I've started building a Rostock and with trying to stay away from timing belts, (mainly because of cost), I've decided to attempt to use spectra line. So the line works well, and I've got the delta platform moving around and stopping at my end stops properly, but I can't seem to fabricate something as a usable drive wheel. I don't have access to a lathe or a machine shop, so there's only so much I can do. I tried using a wooden dowel, but not being able to drill a properly centered hole led to wobbling tension on the line. The next attempt, I have used sewing thread spools. They work well, but the shaft isn't a little smaller so to make up for the size difference, I wrapped it in electrical tape as not looking to "JB Weld" for permanence. The problem I encounter is that as the carriage moves up the rails, the tension changes and pulls the reel up. So this was a good idea but doesn't seem to be working. Does anyone have any other ideas on how to make a reel that can at least last till I can try to print some? Thanks for the help guys!

Edited 1 time(s). Last edit at 12/28/2013 12:09PM by shaggysgti.

The only thing I can think of is either put the string directly on the motors shafts (I'm guessing its going to slip a lot), or find a place to machine a pulley or buy/order some.
I found one site that sells machined pulleys, 7.95usd a piece..add shipping (its christmas) mmm might take a while..
You could try find someone locally or elsewhere that will print you some pulleys.

As you increase the diameter of the "what ever" that the line is wrapped on, you will speed up the head / increase torque needed / decrease the resolution of the system. Don't go to crazy on the diameter of what ever you put on the shaft.

Here are some metal spools: [www.tridprinting.com]

These seem to be of a diameter that is common for delta printers that use Spectra line, which is 18mm. In fact, they're pretty much an exact replacement for the printed ones RichRap designed for his 3DR printer.

thanks for the response you guys. as unclebob stated, I've noticed the movements the delta platform makes under even just putting a single step in the firmware configuration leads to jumpy movements, therefore leading to poor resolution. The vibration of the platform under movement is unmanagable and I think trying to make it work would lead me in the incorrect direction of "making it work." Anyone in the DC area want to print me a set of spools?

If you want to try get some locally from a fellow reprapper try post in that specific area's user group: [forums.reprap.org]

I'm guessing string straight on the motor shafts would work if you use a drop of superglue to fix it to the shaft. Make sure its free of oily fingerprints or else the glue won't grab very well. This page has some good pictures on it, gives you a good idea of what you're after: [richrap.blogspot.co.uk]

Greetings,

TTN

I've been following the richrap blog among a lot of others to get me this far. I think I may try the glue idea and see how far that gets me.

Be very careful with superglue, if you drop it into the motor bearings it WILL seize them.
Just so you know

Haha, thanks for the tip! I'm going to try to tie a simple knot then a small dab of glue on top of that. So the normal spool is 18mm, the ones I've fashioned and actually made work well are 30mm. No resolution at all!