3D Single Pass Skinny Jenny

I have a topo map to carve, and since the make depth of cut is only .15 inches, I’d love to be able to carve with just a single finish pass - no roughing. I have the skinny jenny TBN bit, does anyone have experiece if I can get away with a .15 doc and a 15%-20% step over with this bit? I’m cutting red oak.

What’s the material being used?

You skim-read :grinning: Red oak

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Yes, the skinny jenny can be used without a roughing pass at that depth no problem. Feedrate 180 ipm, plunge 120 ipm. Your detail at 12-15% stepover wont be as smooth as if you were at 10%

You added it… Haha… Wowsa… How did I miss that.

Thanks, Mitz. BJ, you missed it the same way I miss most things these days…at the same time you are reading, there are a jillion other things going through your head…where are my car keys? what’s for lunch? how many women are in the pit right now? do I have enough lotion?

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You are only ever going to get 118.11ipm with that bit no need to set it any faster unless you have altered your zaxis accel rate. TBNs are beasts when it comes to one pass finishing. I have a video of a 1/8tbn cutting .65doc in pine in one pass.

This post has me curious.

I have some 1.75" thick mahogany that I want to carve a family crest. The piece will be approximately 14x20". I have had a good experience in the past roughing with a .25 flat endmill then finishing with a tapered ball mill, but curious if I could do a single pass with a skinny jenny for this piece using their recommended stepover and stepdown. This would save a lot of time if I could do one pass.

I have a stock journeyman x50 with the Makita router, so not at a spindle level yet, but just wondering if I could do a single pass, and if so what feeds/speeds I should use with a new bit.

Probably won’t save time. The step over to get really fine detail is ridiculously tight for hogging out material that the 1/4 can fit.

But it’s pretty model specific - if there isn’t much the 1/4" can deal with you might get away with using just the skinny.

For 3D I usually define it using a 1/4" & 1/8" end mill followed by a small ballnose. Then I look at the preview to see if the clearing bits get me much clearing in return for the bit changeover time I’ll need.

This model will likely take about 20 hours to carve from my past experience carving (which isn’t much). So was just looking for any way to drop some of the time. Maybe its best to just stick with what I know and the process that has worked for me. I saw a video of the LongMill cutting a single pass relief cut and I started thinking and then saw this post so thought I would ask.

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Matt, if you use V-Carve simply simulate both tool paths and check the time. Wild guess would be just comparing depth of cut numbers. If you take a full 1/8 inch with a 1/4 bit, compared to say a 1/16 with a tapered ball nose, you could see it would take twice as long. Taking it further and looking at step over, again multiply by at least four, you are now looking at, (SWAG), 120 hours.

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