Rail Caps

[sawkerf]

Has anyone with a PRT Alpha upgraded their worn rails with the new hardened ones? I understand you just bolt them onto the old rails after drilling a bunch of holes. Just curious for comments, I'm looking at replacing mine soon. Thanks, Kip

[paco]

You mean BWC rails on SB PRT ones?... or buying PRS style SB rails?

Some interesting points to have in mind when considering this change;

*PRS rails:

-they are lower; think proximity switches targets, turnbuckle/spring adjustment length, gantry/Z axis clearance...

-they are bit more prone to accumulate dust as the BWC rails have barely the "V" above the aluminum bar on which they are attached...

-Y axis; you need sized angles or the Y carriage hold down rollers won't fit.

*Capping PRT style rails with BWC rails:

-regarding the size of the rails once upgraded; most of the above points (for the PRS style rails) need to be considered.

I just thought it might be worth to mention what I have been up to myself regarding this. It's just not only a matter of installing it, the change will affect other parts of the tool.

I think it can be well worth the extra hassles... it will be an upgrade and not an "downgrade".

Anyone else is having problem with BWC 3D CAD parts library? I can't get anything else than TS1-SS-1250-7...!?! I tried with 3 different browsers at different times...

[bleeth]

I capped the Y rails on my PRT with Superior Bearing rails. I got the rails made for the larger v-rollers (V3) as they also have more mass in general and work fine with V2 rollers. In order not to have to rebuild the car I had to put some fresh holes in the gantry sides to maintain the same distance between rails and also had to reposition the prox switches, but it really wasn't that big a deal. You do have to drill a lot of holes. The result is well worth it.
Great care and checking and re-checking of alignment is necessary. At times I felt like I was setting the blades on an old large planer the hard way.

[ljdm]

What was the cost of the rails - better deal compared to BWC rails?

[Towersonline]

Kip, I did a conversion on a PRT last July. I ordered the PRS rails from ShopBot. They came with the gear rack, aluminum plate and hardened steel rails. I went this way as it did not want to drill a zillion holes in the old rails to cap it. You will need to drill new holes in the C-channel. If you go this route be sure shopbot ships you some shims and new stopblocks. I had to buy my own 5/16 hardware. Fastenal should have the hardware you need. Here are some pix of my conversion. Note the shims under the bolts. Also be careful on the rail spacing. You may find that you will need some shims on the v-roller bolts.


366

367

368

[robredick]

Has anyone out there looked at or tried any of these???

http://www.techno-isel.com/lmc/Products/Iselrails.htm