Hey everyone,

Anyone who have seen some of my other threads may remember that I am trying to source materials in the UK to make a machine similar to the one found on the automatedwoodworks.com website. As most things are in imperial sizes I am trying to source the metric equivalent.

One thing I am dubious about is the timing ‘L’ and ‘XL’ type belt setup. There are other alternatives such as chain however I am satisfied that “I” will be happy with the performance of the belt operation. I only cut basic stuff out so I think it will suffice.

I am writing this thread as I spoke to 2 belt companies in the UK today, the most helpful being Cross + Morse. I like so many others have concerns over the belts either stretching or shrinking or even wearing quickly. I explained the application to one of the engineers who assured me that if setup correctly the belts would perform exceptionally well in this application. I specifically asked about stretching to which he started to explain the advancements that have been made to eliminate these problems. He did say that stretching could occur in certain applications however this is so small that you would not notice it due to the teeth and pulley arrangement.

I also asked about belt tensioning as I have little experience in this. I have used ‘V’ belts on other equipment for years and these were always as tight as guitar strings. He explained that the tension on each belt does not need to be high and said that the length on the belt (not circumference, this is from centre pulley to centre pulley) should be divided by 64, this will give the result of the allowed ‘slack’. E.g. for a 1000mm measurement (pulley to pulley) there should be around 16mm movement in the belt when you move it with fingers. Not sure about you but I found this interesting as I was getting ready to tighten the hell out of it with a tensioning arm!

He explained that by not having the tension ramped up allows the teeth on the belt to actively sync with the pulley. In this instance any unforeseen changes in the belt shape (this includes any general force on the belt) will not result in any degrade in performance. Apparently the meshing of the teeth and pulley in these systems is extremely accurate.
If anyone is looking for timing belt information, Cross + Morse were extremely helpful. Their website is at http://www.cross-morse.co.uk/timing_belt.asp

I am definitely convinced more now that I have spoken to them. I hope this information helps anyone looking for timing belt information anyway.

I just need to solve the ratio and reduction stuff now and I will feel much better. I feel another post coming on....................