Hello,

I have been dropping in every now and then but most of the stuff discussed here is WAY over my head! My name is Shane and I run a part time business supply wood and parts for musical instruments(full time really but I have a day job as well). Recently I have added two computer controlled devices. The first is a mini mill with drives attached by a previous owner (I have no clue who he is) so one day I am hoping to discuss that machine for advice on what I need to do to get it to do what it can do after you all inform me of just that!. But, I also recently acquired a 1999 Precix 5100 3 axis cnc machine (4 x 4 table, 3hp perske spindle). When I took possession of it I didn't really have much time to check it out. Well recently I decided that it should be working and I ran over the machine and had to change all of the XL belts from the servos. The "X" access runs off a timing belt, it is metric, 5mm, 1650 mm long, 25 mm wide, AT5. The ones on the machine are black with a steel band core. I think, because they are black, that they are neoprene. The ones that I ordered for replacement are white with a steel core and I believe they are urethane. So I am seeking advice on the pros and cons of either. I am about to install the urethane ones but thought I should ask before I did that. Also, are there torque specs somewhere to tension these belts or are they just tightened enough to remove sag.

Thanks in advance!

Shane