Workbee 1515: Screw Drive, Tension Method

I'm assembling a 1500 x 1500 Workbee. I want to put my lead screws in tension. My kit wasn't made to have the lead screws in tension. I planned to use Sean Martin's method - flip the endplates & put the bearings & lock collars on the outside. I proceeded with assembly with this intention but when ready to do this I realized that the lead screws aren't long enough to stick through enough to get the lock collar on. I searched the forums & see references to cutting the C-beams a bit shorter, I assume for this reason. Can anybody confirm that this is necessary (that there's not some other method I'm not aware of)?

Also, in the Ooznest instructions it looks like they've got the bearings and lock collars on the outside of both end plates, not just on one side. I like this - the lock collar at each end keeps the lead screw in tension, not the coupler. I feel like I could make this modification as easily as the 'one-ended' method above... I'd just have to cut the C-beam a little shorter?

My assembly is on hold until I decide how to proceed. I'd appreciate any help or advice. Thanks!

Brian

 

Thanks - I like this! I have access to a lathe at work & might be able to make something there. I'm also considering using 8mm dowels & couplers to make something similar, and I have a third idea that I need to think through (I'll post it if it works out).

 

I said I'd post my idea if it worked and I think it did. See attached. I have the luxury of access to a 3000W fiber laser at my work so I made these parts. The pictures should explain it but it basically moves the hardware into the usable space behind the front plate (the space I highlighted green). It would work with the standard lead screw nut, but I chose to use a threaded one because it lets me finely adjust the position on the lead screw (and therefore, the tension).

Right now I only have this on the front. I made similar parts for the back that I may or may not install. I don't like that this is pulling on the motor coupling & putting this in the back would take care of that.

I just got my machine moving yesterday & notice whip on my gantry lead screw. I don't know why I didn't think about it until now... maybe because it wasn't mentioned in the video & posts I referenced, but I might make & use your extension there instead of my system, because doing mine would require the end plate to be removed & replaced & I'm not sure I want to do all that.

Update: i figured out how to add my bearing plate to the X axis... just remove the motor & slide the lead screw out a bit. I drilled (2) holes in the end plate, mounted my bearing plate & put it all back together. Now all three lead screws are in tension.