View Full Version : How to preserve bits?
matt_bernhardt
07-23-2008, 05:23 PM
Hello, I'm apparently looking for some refreshers on how not to dull a router bit - are there any general overviews posted anywhere I can review? I just ran through a 1/2" diameter end mill in far, far too short a time and I'd like to see what it is that I'm forgetting.
Machine:
PRS Alpha 96
3.25 HP Porter Cable router
Bit:
1/2" diameter 2-flute up spiral
Material:
laminated particle board (milled surface job)
Operation:
1/2" cut depth, 0.5"/second move speed
21,000 RPM
Gary Campbell
07-23-2008, 05:30 PM
Matt..
I am not sure that all of this applies to you, but in most cases heat it the killer of carbide bits. To decrease heat, increase chipload. Lower RPM, Increase move speed. You may want to measure your chipload and use the Chipload Calculator in SB3 [T] [L]
Gary
coach
07-23-2008, 07:22 PM
I cut laminated particle board (3/4") on a regular basis
Right now I am using up cut spiral at 18,000 rpm at 3.5 ips. That is with a 1/4" bit.
I have gone faster but my smaller parts were moving so I stay at 3.5.
I can estimate my cuts for 2 months total over 2000 feet of bit use.
I also have good results with compression bits for smaller parts.
I also have an alpha with a 2 h.p. spindle.
Dave
beacon14
07-24-2008, 12:11 AM
You might have better results with a downcut spiral, since it will leave a cleaner top surface you can use faster move speeds and still get a good cut. The faster move speed will help prolong the life of the bit.
I use a 1/4" compression spiral and can typically cut 30 or more sheets with a bit at 5.5 ips.
coach
07-24-2008, 07:15 PM
ever had to cut with laminate side down?
I cannot get through laminate on entire part.
No matter if I try to go .030 deeper than thickness.
This only happens with lam down.
Not meaning to hi-jack the thread but seems appropriate at this juncture.
Thank you,,,,Dave
beacon14
07-24-2008, 07:29 PM
Not sure why you would not be able to cut through laminate as a bottom layer. I have cut 2-sided plywood and MDF both 1/2" thick and 3/4" thick and had no problem with a 1/4" compression bit. I usually leave a skin of .02" on the rough pass and then do a clean up pass.
What exactly happens when you try it?
coach
07-24-2008, 08:54 PM
David, the laminate is actually left in tact.
The paper is cut away but I cannot seem to get through.
I only cut with lam side down when the board is warped with ends curling up.
I was just thinking maybe a lead in off the material would do it. I am plunging right now.
Today I cut a tool path 3 times and added .010 each pass for an additional .030 total on top of the .010 I normally go through.
Maybe my bits are dull on the tip?
I have used them for 3 or 4 months but the quality is fine except when I cut lam down.
Thanks......
Gary Campbell
07-24-2008, 08:59 PM
David M...
Are you sure that your bit has plunge geometry?
Gary
coach
07-24-2008, 10:22 PM
Gary,,absolutely..........not.
I never knew it was even an option for the bit I use.
I have no problem cutting through the laminate and the particle board when the laminate side is up.
Can you suggest a bit for me to try?
Thanks Gary,,,,,,
Dave
Gary Campbell
07-24-2008, 10:34 PM
David..
David Buchsbaum cuts miles of Melamine. I do not. We did a few cuts last month using a compression from Centurion and it cut well.
Maybe David will chime in with his favorite.
Gary
beacon14
07-25-2008, 01:30 AM
For particleboard core melamine I use a single flute 1/4" compression spiral from routerbits.com and cut full depth less .02" in one pass. For plywood and MDF core panels I use the 2 flute compression bits from Centuriontools.com and usually take two equal depth passes for my roughing toolpath.
jerry_stanek
07-25-2008, 03:24 PM
The best way I found to keep bits sharp is put them in their own case and not use them. But I know that youwant to cut with them so like other people have stated is try to keep them cool when cutting.
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