MILLING PHENOLIC RESIN

[THEMARKHOLM@HOTMAIL.COM]

Can anyone suggest an appropriate MOVE speed and bit-rotation speed for milling phenolic resin? I'm clearing 2.25" dia. circles that are .375" deep from .75" thick PR. I'm using a .25", double fluted router bit. Any other comments would also be welcome.

TX,
MH

[sheldon@dingwallguitars.com]

I just did some aluminum at 5/8"/sec @ 20,000 RPM. I could have probably pushed the feed rate up another 25% at least. I think that .625 - .750"/sec would be a good place to start for phenolic.

Are you going to use coolant? Phenolic scorches pretty easily.

[THEMARKHOLM@HOTMAIL.COM]

Thanks for your suggestions on speeds. I'll start there.

I had not considered coolant, however. I am not set up for any kind of liquid coolant delivery. It's my hope that a controlled feed rate & bit speed will eliminate the need for coolant.

I'm doing my first test run tonight with my fingers crossed.

MH.

[pappy]

Mark,
Liquid coolant can be very messy and do damage to your spoilboard. Consider getting the "Cool Tool".
at www.arizonavortex.com . I have one for cutting aluminum and it works wonders. Powered with compressed air and aim it at your bit. The output will go down to 100 degrees cooler than the input.

[MARK HOLM]

I ran my first prototype last night. I used a 1/2", double-fluted bit rotating at 21K and moving at .75 IPS. It seemed to work fine. Thanks for all your help.

[sheldon@dingwallguitars.com]

Doug, what size of nozzle do you have on yours. Mines 3/8" I think, so the output is pretty low pressure. I haven't tried it on aluminum yet.

[pappy]

Sheldon,
Mine has the 3/8 also but, you don't need a lot of pressure. More pressure doesn't help; cool helps.

[the_whaley]

Just plain kerosene works great also.

[grant@shopbottools.com]

Sam, I would caution you there. Typically it's not a good idea to use flammable material as a coolant, given how easy it is to create friction heat and sparks with a router bit. Even WD-40 can be hazardous. Be careful. Many if not most machine coolants are a lubricating oil that is mixed in low concentration with plain water. As others have pointed out, those liquids are not great for MDF. Liquid cooled cutting is best done on a special jig or over a plastic spoilboard.

[gerald_d]

Grant, your post on the safety of using flammable liquids as a coolant is of course perfectly valid.

But you raise an interesting subject - who takes the responsibility for the safety of any advice published on this forum? According to this notice (http://www.talkshopbot.com/forum/cgi-bin/discus/show.cgi?tpc=373&post=1653#POST1653), ShopBot says: "All messages and postings become the property of ShopBot Tools". Is your post above, on behalf of ShopBot, made because of your responsibilty for what has become "your property"?

[stevem]

I would suggest that Mike’s Hard Lemonade makes a perfectly fine coolant. Especially on a hot summer day.