Cutting tempered hardboard question

[steve_g]

I need to cut a large quantity of parts from tempered hardboard... In the past my CNC cuts with in this material have been less than stellar and a search of this forum and the WWW would indicate that my experience was not unique! My question is:

Has anyone found a bit, speed, and A cutting strategy combination that cleanly cuts ⅛" and ¼" tempered hardboard?

Thanks!
SG

[kartracer63]

Is your hardboard smooth on both sides?

I've had success sanding the surface of the hardboard with a random orbital sander (120 grit) lightly around the edges to clean things up. It leaves no evidence of sanding on the surface, but does a great job cleaning up the edge fuzzies.

[kartracer63]

Also... I've thought a compression bit might work better than a regular up-cut or down-cut spiral bit. But, I haven't had to cut any hardboard lately.

[steve_g]

Eric...

This is the white coated hardboard often used for inexpensive dry erase marker boards... I assumed they were textured on the back and smooth on the front, but I don't really know for fact.

SG

[myxpykalix]

The hardboard i've cut was that brown "masonite"(?) and that cut pretty cleanly with a spiral bit except that the paper facing seems to hang on the cut edges. But taking a piece of sandpaper and a couple swipes on the edges cleans them off cleanly.
I'm not sure if it is the same thing or not...:confused:

[steve_g]

http://www.lowes.com/pd_16605-46498-300_0__?productId=3015239&Ntt=white+hardboard&pl=1&currentURL=%3FNtt%3Dwhite%2Bhardboard&facetInfo= (http://www.lowes.com/pd_16605-46498-300_0__?productId=3015239&Ntt=white+hardboard&pl=1&currentURL=%3FNtt%3Dwhite%2Bhardboard&facetInfo=)

This material is like the denser Masonite products, a very deep brown almost black. Previous attempts to router cut tempered hardboard resulted in fuzzy cuts. Since this material will be used as modern day "slates" I had hoped to avoid damaging the face by sanding... That and the shear quantity makes me want to avoid double handling

SG!

[srwtlc]

I cut the same or similar stuff from time to time. A good downcut bit cutting slightly over thickness on a fresh flat spoilboard with vacuum holddown. I follow up with a slight beveled edge with a sander to soften and clean up the edges. I have used a small 45º chamfer bit at the router table to chamfer the edges and clean them up, but because it's 0.125" thick, it tough to get it to work with a pilot bearing.

[genek]

The easiest way to rout the edges of thin material like the Masonite is to use the dremel tool with the base they have miniature round over bits... Actually the dremel will work better on the thin sheets than any other. Drimel bits for this do not have a ROLLER bearing, it has a glide surface to follow the wood..

[steve_g]

Well, here's what I came up with...

3/8" down spiral "O" flute, 16K rpm, 3 ips, cut in the conventional direction. As Scott suggested, I had to "over cut" into a new spoil board.

The coating on this material is awful! Blowing dust off with compressed air is just as likely to pull off a chunk of the coating! Any bit other than a spiral down cut either lifted the coating or "flared" the edges. The parts were reasonably clean with the above settings but I also lightly sanded them in bundles of ten to knock off loose stuff. Any attempt to bevel or round over the edges just chipped the paint making them look bad.

SG