Plunge Burns?

Hello,

I’m cutting 60x35” oval countertops out of 1” MDF that has bee laminated with melamine.

Using a 1/2” straight plunge 2 flute and did these 3 tests at the feeds and speeds shown. Bit was hot after tests 1 & 2, not so much on #3.
Cuts quiet, with nice smooth edges and no chipping.
My question is how to get rid of the burn marks shown at the plunge point?

Thanks so much for any help.

Attachment 31671

don't plunge ramp it in. You got to watch fires on laminates.

What software are you using? There should ramping options. Look in the manual on how to set them up.

Phil

OMG. Duh. Thanks Knight and Phil!
I totally forgot about that option:o

got to watch it on what your cutting you can start a spoilboard fire. I did one or two test holes with a downcut bit and started a fire.

In regard to fires, I was cutting some hard maple with a downcut and had to drill a few holes as the last part of the job. Rather than changing bits, I thought it would be a lot easier to use the downcut. The first hole sent a lot of smoke up the dust collector, the second sent flames shooting out of the hold. I hit the stop button. Lesson learned. Drilling holes with a downcut is not a good idea. I finished the job with the right bit.

Quote:

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Originally Posted by coryatjohn

In regard to fires, I was cutting some hard maple with a downcut and had to drill a few holes as the last part of the job. Rather than changing bits, I thought it would be a lot easier to use the downcut. The first hole sent a lot of smoke up the dust collector, the second sent flames shooting out of the hold. I hit the stop button. Lesson learned. Drilling holes with a downcut is not a good idea. I finished the job with the right bit.

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I always drill (doesn't matter the material) with boring bits designed for CNC or boring machine work. I don't want to have the scary experiences you have had with smoke and fire. Haven't done any metal work so not sure how I'd approach that if the project presented itself.

Toolstoday.com sells a whole line of Amana boring bits, metric and english. I've been using mine for 10 years and they are still working as well today as the day I bought them.

I peck drill holes in plywood with a downcut bit first, but only to about 0.1" into the material to keep the veneer from chipping up. Then I come back with an upcut to full depth.
I had the same experience as coryatjohn. It only takes one scare like that to not do it again........usually.
Lots of good experience on the forums of what to do and more importantly what NOT to do.

I can drill holes sometimes with a downcut but it depends on the material and how many. a compression bit works well as long as you do peck drilling. but if I am doing a lot of holes and it is a common size I will use a bradpoint bit.

Another option, which we use 99% of the time is to use a smaller diameter tool and do a spiral profile to the inside of the vector. Not only do you get clean hole with no burning but it allow to run the holes a lot quicker.
Gary