My paddle wheels/drive system.

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Talisman, As stated my CNC is home made and uses a normal router to drive the bits. The bits are listed as 'Solid carbide end mill' I normally use a 2 mm bit with a feed rate of 1mm a second on the brass and up to 6 mm on 2 mm ply. I have not used any cooling as the feed rate is slow enough that I have not had any problems. The only problem that is occurring is that the bits are ' Up Cut' and they lift the work off the table so any tabs that I put in to hold the work together until I am ready to remove it are sometimes taken out. I am working on a system that applies slight downward pressure on the job to keep it flat on the table during cutting. A straight cut bit would probably be better, but my supplier does not appear to have any. So far I have not broken any bits at all. I am using Mach 3 on the CNC. I would think that you just have to slow the travel speed down and keep the bit speed up, depending on the size of the bit you are using.

Graham

[R.G.Y.]

I made a set of wheels in brass, but because I had sability problems I scraped them,and  made my wheels from aluminium. Many big advantages lighter than brass and eseier to cut,(I riveted 4 pices of sheet together and cut them out on my scroll saw useing a modifid junior hack saw blade) stronger than plastic, and pivot pins if made from steel or brass can be soldered in with out sticking to the main parts.