What cutter is best

[Evan Meier]

Good afternoon everyone,
My wife asked that I make a set of chairs for our kids coloring table. I was going to cut them out of oak and wanted to try using the CNC, because why not. I have done very little hardwood cutting and was wondering what people would recommend for a bit. The cut depth will be one inch. I'm partial to 1/4 inch bits for no reason other then that's what I have used in the past. I have a 3hp Porter Cable router for a head. Also wondering what feed and speed you would recommend with your current t recommendation
Thanks
Evan

[Mark Bolton]

I would be looking to the largest tool you can run with an offset in the toolpath that allows you perhaps 2-3-4 passes (whatever your comfortable with) and the final pass includes and offset that takes a full depth skim pass to clean up any witness marks from the previous pass.

Your tooling and depth of cut, feeds, speeds, will depend a lot on how you intend to fixture the parts.

I would not be in the 1/4" tool range with a 3HP router for this job unless you need it for specific radius'. Your router is capable of far more than 1/4".

What fixturing, software, and so on, would help people give you better input.

[Jim Becker]

Evan, when it comes to speeds/feeds/tooling, it will be helpful for folks to know what CNC machine you have. It's not just about the router/spindle...the machine itself is going to have a big influence on what's the best way for you to proceed.

[Martin Wasner]

I've said this a few times, I rely on the Vortex Tool app.

Punch in the material spindle hp, type of cut, and tool diameter and it spits out a recommendation.

I agree with Mark on using a ½" bit. You'll get less deflection

[Jim Becker]

The Vortex app is very useful as a starting point, but for folks with small and/or hobby machines, there may need to be a more conservative approach because of the physical limitations of the machine. For big industrial/production machines, it's a little easier to plug things in and go. That context is important here.

[Evan Meier]

Sorry it took a little while to reply
I have a probotix meteor. It is not a production machine by any means. It is a lead screw machine that claims it can travel up to 200 ipm, although I have never pushed it near that high.
Usually I just screw my work down to the table, a vacuum table is in my plans, just haven't gotten the time to make it yet. I use vcarve pro to do my tool paths.
I was mistaken about the router, it's a 2.25 not a 3hp
I'm not very concerned about cutting as fast as humanly possible, if my wife hears the machine running she assumes I'm busy and keeps the honey do asks to a minimum...

[Martin Wasner]

The Vortex app is very useful as a starting point, but for folks with small and/or hobby machines, there may need to be a more conservative approach because of the physical limitations of the machine. For big industrial/production machines, it's a little easier to plug things in and go. That context is important here.

I'd assume some of that is figured in with the amount of spindle power?

[Jim Becker]

I'd assume some of that is figured in with the amount of spindle power?

That accounts for the cutter (The OP is using a router, not a spindle) but not necessarily how fast you can drive it based on the machine construction, resistance to flex and stepper/servo motor power. Your beast can probably take anything you throw at it. Smaller machines...not so much.

[Martin Wasner]

That accounts for the cutter (The OP is using a router, not a spindle) but not necessarily how fast you can drive it based on the machine construction, resistance to flex and stepper/servo motor power. Your beast can probably take anything you throw at it. Smaller machines...not so much.

Considering the more robust machines are 10+ hp, I'd think all that would be factored in or assumed. I could be wrong.

[Jim Becker]

Until the OP helps us understand what machine he's using (and given it has a router, rather than a spindle, doing the cutting, it's likely a smaller hobby level machine) and that's going to affect speeds/feeds. There are plenty of smaller industrial/production type machines that use spindles in the 1.7-4kw size range, but yes, the bigger machines tend to be much higher powered.

[Mark Bolton]

The horsepower or machine isnt really going to have a ton to do with it in this situation in my opinion. Cuts will more than likely be super conservative regardless of the tool. Largest cutter possible dependant on fixturing, shape of the part and so on. Multi pass with a final cleanup pass. The router stated will handle far more than the 1/4" tool. A need to make these tooling selections into rocket science isnt really applicable when its not the aim to run the machine at the edge of its capacity. A 1/2" or even 3/4" diameter, two flute cutter, provided it will get into all the profile it needs to would run all day in that router with conservative cuts and give a far better result than a 1/4" screamer.

[Bill George]

I just used my first ever Down/Up Cut spiral bit this afternoon. Granted it was only .250 bit and it was in .750 inch thick soft pine, but the chips just flew and the finish was perfect. I was not pushing at 12,000 rpm and 100 ipm.

[Mark Bolton]

I just used my first ever Down/Up Cut spiral bit this afternoon. Granted it was only .250 bit and it was in .750 inch thick soft pine, but the chips just flew and the finish was perfect. I was not pushing at 12,000 rpm and 100 ipm.

Compression spirals are definitely nice. Ive never had the need for the cost on solids where a less expensive straight brazed cutter performs well. But I could definitely see the spiral helping in a smaller spindle. Running the compressions on sheet goods is a dream.

[Jim Becker]

Bill, I really enjoy my compression spiral bits for when they are the right tool for the job. Aside from cutting out sheet stock, i also use them for pocketing boxes, just making sure that the first pass is slightly deeper than the break point on the bit. I also mostly use the .25" version for what I use them for, but have a .375 and .5, too. The .375 got the nod when I was cutting Advantec for some NUC (nuclear colony) bee boxes for Professor Dr. SWMBO... "like butta"...

[Bill George]

I was impressed with the finish, only sanding was to get the remains of the tabs.