Host Neil Butterfield
February 25th 2006
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Members in Attendance
The meeting was held at Neil Butterfield's shop.
Neil gave us some basic insight into knurling, followed by a demonstration on his lathe.
There is not much written material about knurling. Many project descriptions give detailed instructions about how to make parts, but when the knurling is involved, they often just say knurl the part.
Neil has developed his ability to knurl and offers these basic first rules to get the job done successfully
Once you start a knurl, do not raise the cutter from the work piece until you
Knurling is primarily material displacement. It is not material removal like making chips. The displacement requires high pressure on the work piece and the equipment. Light equipment does not handle the pressure as well as heavier equipment
Neil showed us several types of knurling tools.
He recommends using the scissor type knurling tool for best results. This design relieves some of the pressure the equipment must absorb in the process by the 180 degree opposed action of this tool.
ENCO's latest sale flier shows this tool model number DR505-4518 for $48.99.
(Special Note as of 28 February 2006, This price is in error and should be some $70+ dollars. ENCO is honoring the advertised price now however. )
To increase tool rigidity and minimize the possibility of tool movement during the process, Neil modified the mounting of the scissor type tool. He removed the bar that would be used to mount the tool in the traditional tool holder. He replaced this with a custom made mounting block that attaches directly to the cross slide. The mounting block also has a lip on 1 side that bears against the side of the cross slide for alignment and added stability.
Once the work piece is center drilled, clamped in the headstock, the live center is brought up to the end of the work piece, and the scissor knurl tool is placed on the work piece at the starting point for the knurl, you are ready for the knurling operation.
When selecting the knurling wheel size to use, keep in mind the need to have the knurl size fit the diameter of the work piece so you make only full diamonds all the way around. If you miss this step in planning and selecting you knurling wheel, you will not get a satisfactory knurl.
Neil passed out a worksheet for figuring the knurl wheel size to use. This sheet is available on request.