Cnc router bits

[serge]

all the time I used the regular router bits from amana but now they are offering me cnc router bits and somebody else talked about compression bits, can anybody help me with more information and experience

[paco]

Serge,

that a wide topic... to get you a start, compression are designed to cut clean on laminated sheet good; that is, compared to a standard straight edge router bit, it has lower cutting edge(s) that sheer the material upward and upper cutting edge(s) that sheer the material downward which "compress" the cutting action toward the center of the material (usually laminated sheet good).

Do you have more specific questions?...

Oh, and compression are usually somewhat more expe$$ive than standard router bits... but well worth if you're looking for SUPER cut finish!

[richards]

I use 3/8-inch and 1/2-inch, 1-flute compression cutters when making one-pass cuts in melamine coated particle board. If I make multiple passes in melamine coated particle board, I use a down-cut spiral cutter for the first pass and an up-cut spiral for the final pass to minimize chipping. For MDF and particle board, I use straight cutters. For baltic-birch, I normally use straight cutters unless the cut demands no tear-out, then I use the compression cutter or up/down cutters as if I were cutting melamine coated particle board. Onsrud makes excellent cutters. When I can't get Onsrud cutters, I mostly use Whiteside - which are available locally. I haven't had much success with CMT or Freud spiral cutters. Both brands are excessively noisy at the speeds that give the proper chip-load for the material being cut - meaning that something is wrong with the speed or feed.

Before I started using a spindle, the extra cost for the compression cutters was mostly wasted because the Porter Cable router just wasn't big enough to make a one-pass cut.

[bleeth]

Onsrud has some terrific compression bits in which the upcut portion is short enough that you can use the same bit for a 1/4" dado or a 3 pass cut on 3/4" goods and get clean cuts. Although many companies produce more generic versions, no-one has the inventory of specialty bits for cnc like they do. Their new catalog just came out and if you don't have one, get one. It is a great information resource.

Dave

[Keith Blaine (Unregistered Guest)]

Are you guys using vacuum spoil/bleeder boards? I'd imagine that the spoil board acts as a very good zero clearance surface, and hence you only need a downcut bit.

Thoughts on this?

FWIW, I use her-saf downshear insert bits. Very economical and great performance.

[richards]

I've had significant chipping when cutting melamine coated particle board with a downcut spiral and my Fein based vacuum system. Using a compression cutter worked best for me.

[beacon14]

With material other than melamine often a downcut will give acceptable results even with through-cutting. If the material is held tightly to a relatively intact, smooth surface, the cut can be quite clean, but it can also degrade over time as the groves in the spoilboard wear and tend to enlarge when running the same pattern repeatedly in the same place.