Gentlemen, I recently completed my railbender featuring three skateboard plastic wheels mounted with bolts and bearings (overkill, but real smooth) on a cheap Harbor Freight drill press vice.
I ended up doing a number of machining operations on the vice itself to tighten up tolerances, and installed a much longer steel plate under the moveable jaw, to prevent it from tilting fore and aft.. The main point I offer here, is that I cut the grooves in my skateboard plastic wheels, so that both Code 250 and Code 334 rail can be bent using one set of rollers. The base of both rails rides in the center slot (neither size rail touches the bottom of the groove). The heads of the difference code sizes ride in separately-cut grooves (higher up for Code 250, lower down (upside down rail) for Code 334, and also have clearance between the head and the bottom of the roller groove. ONLY THE WEB OF THE RAIL receives pressure from the rollers. I have noticed no rail twist in the test pieces I have run through the bender. At least one commercial rail bender in our local club functions in a similar manner, i.e., only the web is in contact with the pressure rollers. I read somewhere that the outside pair of rollers should have a slight amount of vertical play on their axle shafts so they will automatically seek alignment with the driving roller. Works for me. I think that a true, square edge of the roller where it mates up to the rail web may also contribute to absence of twist. This assumes that the straight die-drawn rail stock from the manufacturer has no twist in it. My supplier, California & Oregon Coast Railway, once received a shipment of rail stock that had a twist in it from the manufacturer. That rail was useless, and had to be sent back. If anyone would like a photo of my bender, email me with your email. And I will forward a shot or two. radar 3 at charter dot net (Edit to achieve standard email format). Please, indicate whether you are using dial-up or hi-speed connections. That makes a difference in the size of the picture file to be sent to your Inbox. My present device has a steel driving wheel with the driving ridge knurled and then slightly flattened with a light touch of a file. All this fancy stuff is not necessary. A plastic wheel machined to match the driven rollers would have more than adequate friction to work just fine. One additional note: Future copies of this bender will have the twin rollers mounted toward the two ends of the moveable vice jaw. This avoids a conflict between the drive wheel axle with the original acme threaded rod which attaches to the center of the moveable jaw. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://postfix.45mm.com/pipermail/sslivesteam/attachments/20060616/4cdd7b9f/attachment.html _______________________________________________ SSLiveSteam mailing list Send messages: [email protected] Cancel subscription: http://postfix.45mm.com/mailman/listinfo/sslivesteam Rules: http://www.45mm.com/sslivesteam_guide.html
