Rotory tool speed?

[darkling27]

Hey everyone, just set up my new desktop cnc machine and pretty new to all this woodwork stuff, so decided to head here for wisdom

Basicly, i was wondering how fast i should set my rotary tool for when im removing material. Is it just a case of putting it on a fast speed and letting it do its job, or does it vary on material, size of bit, type of bit, and number of flutes? Sorry if this may be a obviouse question to some of you, but id rather not break my cutting bits or ruin what im cutting out by doing something stupid

The routing bits i have are a....
4mm 4 flute flat,
10mm 2 flute flute,
1mm 2 flute ballnose,
1.5mm ballnose,
and a 2mm 2flute ball nose.

Being new and all, i decided to just buy what i think i would use, but im pretty sure i would need to buy more at some point.
And help would be very much appreciated thanks

[antonzedd]

There are different speeds you should use for different materials absolutely. But since the machine you've got is a mystery to everyone your asking a question to I'd say experiment, there's lots of info on google about cutting speeds for plastic and wood etc. By the way, your new and you will break bits finding things out for the first time, so try and do your cuts virtually first cut air, get used to your x,y,z and work coordinates. Best of luck, cheers

P.s. NEVER CUT DEEPER THAN THE DIAMETER OF THE TOOL YOUR USING!!!!!!! - The number one rule to remember!!!!!!!!!!!!!!

[darkling27]

This is the machine im using, and it is fitted with a Kress router

z90router

[dlwoodworks]

As stated, different speeds for different materials and results. I use a Shopbot CNC for cutting cabinet parts as well as carving signs, table tops and fireplace mantels. For 3/4" plywood cabinet parts, I use a 3/8" mortise compression bit and my first pass is done using a climb cut and I cut to within 1/32" of the full 3/4" depth. I then do a second pass in a conventional direction to go through the plywood, cleanup and complete the cut. For drawers I use 5/8" baltic birch and cut with a 1/4" mortise compression bit the same way as the 3/8" mortise compression bit. I've never broken a bit with this approach.

When carving something my roughing passes are done with a large bit. For large carvings I will use a 1/2" ballnose and take 1/2" deep cuts. For smaller carvings I will use 1/4" ballnose and take 3/8" cuts.

Two other very important factors in cutting and carving are feed rate and spindle/router speed. If your bit is making high pitched screaming sounds it is starved for wood. You need to either speed up your feed rate or slow down your spindle. You should see chips coming out, no saw dust as this indicates to slow a feed rate or to fast a spindle speed.

When you complete a cut, and the SPINDLE COMES TO A COMPLETE STOP, you should be able to touch the bit and it should be about room temperature. If it's hot to the touch you are burning the bit and shortening its life.

[ger21]

P.s. NEVER CUT DEEPER THAN THE DIAMETER OF THE TOOL YOUR USING!!!!!!! - The number one rule to remember!!!!!!!!!!!!!!

Completely false, as Don has mentioned. Depending on the strength and power of your machine, you may be able to cut up to 3 times the bit diameter in a single pass. But I wouldn't recommend it on the OP's machine.

Here's a link to good rpm/feedrate info. Choose your material, and find a similar tool made by Onsrud, and it'll tell yo how fast and at what RPM. http://www.onsrud.com/xdoc/FeedSpeeds

I run a 1.5mm ballnose (actually 1/16") at about 18,000 rpm and up to 150-175ipm (~4000mm/min). Larger bits require lower rpm's, but rpm is directly related to feedrate.