Rolly Munro – 22 May – Mark von Dadelszen
I’ve been cajoled into reporting on Rolly’s demo on 22 May. At the outset I should confess some bias – I believe that Rolly is a huge asset to woodturning in New Zealand, as well as being a really genuinely nice guy. Oh, and he’s a pretty good turner and produces some awesome woodturning tools, too!
Rolly ended the day by showing us various texturing and carving techniques, taking much of the mystery out of those processes. But he spent most of the day talking about his tools, what he said should have helped everyone present, of whatever level of experience, understand more about how and why their tools (whether or not they are Rolly tools) cut (or fail to do so). So, what gems of information did we learn?
On tools in general:
oNo matter what tool you are using it has to be sharp. If it isn’t it, won’t cut properly. Especially with carbide cutters, a hone makes a huge difference to renew a sharp edge.
oSharp tools produce longer shavings, but blunt tools produce shorter dustier shavings.
oIf you have to force the tool to get it to cut, it’s not sharp.
oA diamond grinding wheel produces a sharper tool than a stone grit wheel – especially when you have two diamond wheels of 240 (for shaping) and 600 grit (for sharpening). Rolly sharpened a bedan tool (it has a wide flat bevel which was the perfect way to show this) with his 240 and 600 grit wheels – and there was a significant difference. Seeing that was certainly to believe it! These diamond wheels are expensive, but over time will save costs. When sharpening, present the heel of the bevel to the wheel first, not the cutting edge.
Specifically on Rolly tools:
oRolly supplies two types of cutters, High Speed Steel and Carbide. Apart from a price difference they have different profiles (therefore cutting differently):
Click here for a detail diagram and report in Adobe PDF what Mark has written up.
oFor roughing out with a Rolly tool use the HSS cutter with a maximum 0.5mm gap between cutter and depth gauge.
oRide the bevel of a Rolly tool to control the cut – if you ride the depth gauge the tool will read the wood on the gauge, causing chatter and ridges on the surface of the wood.
oWhen using a Rolly tool other than for hollowing run the lathe at whatever speed produces a good cut.
oWhen using a Rolly tool for hollowing a lower lathe speed of ±500rpm is about right, and keeping the tool level with the centre of the work is critical.
oTo remove the “pip” in the centre of a bowl or hollow form, move across the bottom from “8 o’clock” to “2 o’clock.”
