Gerhard,
I'm sorry, I didn't realise you are using a fairly small machine.
A straight knurl only needs to use one wheel, and are very easy to make yourself.
Marv,
I can only go by what I was always told by the people who taught me, and that was a knurling wheel is actually cutting into the metal, and the pressure used was to make the knurl cut deeper. That is why I always use a lot of oil or coolant on it when cutting, to clear away the swarf. Using that system, it has never failed me, so I would class the information that I have is correct.
I know that pressure is involved, and that the metal is thrown upwards when cutting, and I use that quirky by-product to allow me to expand things to make tighter fits. I class that more of burrs rather than deformed metal, and if just making a normal knurl, I file or cut the burrs off before use.
Where I think people go wrong, is that when cutting a knurl, they think it should form straight away, as so overload the knurling tool which then acts like a forming tool. It might take me ten minutes to cut a small knurled handle by taking it very steady on the pressure. Doing it that way, even people using small lathes can cut a knurl using a side loading tool rather than a scissor tool.
Another point to raise is that there are different sizes of knurl pattern, and you should use the correct one for the size and depth you require. It is no use forcing a heavy knurl using a fine wheel, it will look deformed and awful.
Unlike most people who use the same blunt wheels for years on end, I do replace my knurl wheels when pressure forming takes over from a cutting action, just like I would do with any blunt cutting tool. The wheels are so cheap, it is, as far as I am concerned, foolhardy not to have them in stock, just like replaceable carbide tips.
John
