Well I haven’t posted for a while, because I have been working on my Decking. As well as that though I have been finishing off the OverlapStrap, since my last post I have made several improvements, such as beefing up the X-Carriage
Improving the way the Thermal Barrier was fixed to the CrudeStruder. I also added the finishing touches such as mounting the end stops, wiring up all the (pre-assembled) electronics, and general finishing off needed to test everything.
Then this weekend after a lot of tinkering and a lot of help from Tonokip via IRC, I was able to print my own derived version of Nopheads Mendel Pulley which I re-designed in openscad.
It looks pretty ugly, but I am quite pleased that its roughly resembles the pulley that I was aiming for. It did however need some cleaning up, this is what it looked like straight of of the printer.
The problems I am having are
- Getting the right setting for e_steps_per_mm
- Getting the first layer to stick (I am currently printing directly onto MDF so no surprise)
- Strings and crud attached to one side.
- Detail level is too low. (The pulley is not detailed enough to have teeth yet so its not usable)
Giles Bathgate 
A Print! At last! Wonderful.
Will probably copy your y bearings. If I build one at all. Looking/hoping that BotHacker puts out a kit for his t-rap. If not I’m back on my own and your hardware store bearings are great.
Thanks for the good works.
Arvin
Thanks.
If you can, I recommend having a set of bearings below the y axis skates, Like I have done for my x-carriage as you can see above. It allows you to clamp up the bearings for extra stability. If you rely on gravity then you should make your bed heavy enough that gravity will provide stability.
I would be really honored if someone else would try out my design. You can see all the drawing files here Not everything is there yet, but ask me for anything that you need if you are interested and I will try to provide them as quick as I can.
Thanks. I was drawing copies in Sketchup. Had guessed 4″ for the z-skate. Good for a guess. I’ll finish drawing them, keeps me off the street, while I wait to see developments with bothacker.
I have made the bearing skates before. Have made a couple of iterations of one like http://buildyourcnc.com/davidkcnc.aspx just really unhappy with the speed of the 1/4″ allthread and my drilling skills. Haven’t found anything better than the expensive belt/pulleys. I’ve about given up on using anything else though. I did buy a cheap drill press recently so maybe my skates will work out better this time!
Hope this shows you what I’ve been doing in Sketchup. If not here’s a link: http://picasaweb.google.com/lh/photo/FtTX5rQ5FwJvYXe_18vyaA?feat=directlink
From reprap
I hope I’m not making a nuisance of my self. This is a simplification of the z-skate that I think will work but I’ll have to do the build to find out. Unless you’ve already tried it?
http://picasaweb.google.com/lh/photo/3it_xTVU6SxE_-4Vwhzewg?feat=directlink
The 4 wheeler design looks interesting. I am not sure how stable it will be though. If you want to get measurements of things there is also the very unfinished Assembly.dxf file you might be able to use for reference.
What would be a good dxf file viewer. I’ve tried a few. Didn’t like any of them.
http://picasaweb.google.com/lh/photo/iFiLLJVA6iEg4LefYSvKVg?feat=directlink
That’s the two z-skates drawn in Sketchup 7. I really like sketchup. Especially the price. I use the free version!
I tried the 4 wheel version today. I’m worried about the stability. I’ll give it another go tomorrow. Worried that the bolts aren’t strong enough.
I use QCad for drawing and viewing dxf files.
If you are using linux you just do:
If you are using windows you can use this installer. Don’t bother with the newer demo version provided by ribbonsoft (The official company that wrote the software) because its limited to 10 mins use.
Thanks for the qcad link. Have become spoiled for 3d being able to pan and orbit in Sketchup. I see I hate 2D now.
Gave up on the 3 bearings on the angle and one on the other side. Inherently unstable like you guessed. With 4 and just one it seemed to work but didn’t feel as solid as it does with 4 and 2. Looks like your design is a winner.
Spend 2 days with lots of drilling and tapping to just verify that just “because you can draw it doesn’t mean it will work”!