Profiling with 1/8 inch bit

[lockeb]

I want to use a 1/8 bit to cut out profiles in a design that is actually a scroll saw project. My reason is to get sharper detail. I haven't been down this path before. Could I get some guidance on feed rate and RPMs so I don't break as many bits? If I am successful with this I want to cut one that has the cut outs with overlapping vcarve letters. Thanks

[Leo]

Generally smaller cutters want higher RPM - so you want 18,000 - 24,000 RPM

Feedrate is all about your machine, the material you are cutting, the thickness of the material, etc.

I did a Scroll saw pattern years ago with a 1/8 cutter. I don't really remember the speeds and feeds but I was new to it and I was running a lot slower than I would run today.

So - just an educated guess for a start point, and assuming 3/16 birch plywood ----- 20,000 RPM - 50 IPM to start, ramp up from there to 100 or 150 IPM. DOC .095 Make sure your cutter is no more than 2 flutes.

Please show a picture when you are done

[Bob Jr]

I posted a reply to this post over here: http://www.cncsharktalk.com/viewtopic.php?f=2&t=4012
Bob

[scottp55]

Just personal experience, but been using this one on material up to .9" to cut out everything from .69"BB Ply to Cherry to Bloodwood and hard Maple for several months now to save material and my fences with Very good luck. All in IPS. This one very picky on RPM though and likes a conventional cut for some reason. 2-2.6, .5, 10-10.5K at .06" pass depth.
http://www.ebay.ca/itm/1-8-CUTTING-BIT- ... 234424da39

Just started using these a couple weeks ago for thinner stuff and seems to have very little tearout. Can't beat the price. Hard Maple cuts clean at 1.1,.5,14K at .065"pass depth but need to cut more before I get max speed before quality of cut suffers.
http://www.ebay.ca/itm/5-1-8-1250-2-FLU ... 58b4c9c913
I usually am conservative on pass depths(half diameter) as I hate to sand and seem to get less deflection by shallow cuts/increased feeds and also haven't broken one yet except by really stupid mistakes.

[lockeb]

I have a shark mako. PC router. The two bits I have are CMT 1/8, 1/4 shank. One up cut,one down it. Do you recc a different bit. I understand high rpm, with many shallow passes. Is that correct?

[lockeb]

Scottp55 I will confess my ignorance. The numbers you gave ...I get the RPMs and depth of cut. Not sure about the other two which is feed rate, etc like "1.1 and .5.

[scottp55]

In Inches Per Second 1.1(X,Y Move Speed), .5(Z Move speed) (Just a Shopbot OS thing)
I would definitely try your bits first, I would really recommend adding ramps (having good luck with spiral ramps) to your toolpath, as I don't know if those are center-cutting.
Remember also that feeds/speeds will change drastically from machine to machine/species of wood and lots of variables. What works for you is best.
Have you seen this? (there's also one on bit breakage).
Keep an eye on your chips, and make sure the carbide stays cool enough to keep your finger on the cutter after cuts.
Good luck.
http://www.precisebits.com/tutorials/ca ... speeds.htm