1+1 Compression VS 2+2 Compression

[tri4sale]

Browsing router bits today, and saw 2 that are the same except for one line in description.

Both are:

Up/Down Cut
Solid Carbide Spiral
1/4 Cut
1/4 Shank
1-Inch Cutting Length
2.5 Overall Length

But, one is listed as 1+1 Compression (model UD2100) and one as 2+2 compression (model UD2101).

Both about same price, both made by Whiteside.

Can someone explain the difference between the 1+1 and the 2+2 and what it means in real world application?

thanks

[steve_g]

Daniel…
1+1 is one up cut flute, one down cut flute. 2+2 is two of each… some materials cut better with one, some with two. One flute can evacuate chips faster, two can cut smoother.
SG

[Tim Lucas]

1+1 is single flute and 2+2 is two flute

:)

[tri4sale]

Daniel…
1+1 is one up cut flute, one down cut flute. 2+2 is two of each… some materials cut better with one, some with two. One flute can evacuate chips faster, two can cut smoother.
SG


I mostly cut Plywood (Baltic Birch, Oak & Blondewood (that's what it's labeled as at Lowe's)) and potentially some MDF, do you recommend one over the other? I like smoother cuts :)

[steve_g]

My preference is the 2+2 but will buy whatever is on sale!

SG

[tri4sale]

My preference is the 2+2 but will buy whatever is on sale!

SG


Thanks, I was leaning towards that one, $2 cheaper :) I'll give it a try and see how it does.

[Justin G]

Am I correct in my understanding that since we are talking compression bits, there really isn't any evacuation to speak of, and going with the smoother finishing bit would be the better choice?

[steve_g]

Justin…
I was hoping some of the fellows who use compression bits day in and day out would speak up here...
The term “compression” comes from the fact that the upper and lower cut direction is toward each other… theirs no “packing” as such. There’s still plenty of sawdust to get out of the way! I think another overriding consideration is the bit diameter… If you’re looking for 1/8” and even some manufacturers ¼” bits, are only offered in 1+1. A quick look around the web today showed 3+3 and 4+4 bits designed to cut at 1500ipm @ 40,000 rpm. These bits are only offered in larger diameters however! Today I found rougher finisher compression bits designed to cut composite materials at 3500ipm, ridiculous speeds!
I think the bottom line is, if your income depends on cutting hundreds of sheets of material daily, you better be consulting with a manufacturers reps!
SG

[Ajcoholic]

I use both single and double flute compression bits. Both cut just fine with the proper feed speed and rpm. I prefer 1/4" and 3/8" dual flute and a feed of 360 to 400 inches per minute, and 11,000 rpm or thereabouts. I adjust until there isnt any squealing.

The majority of the cutter, say, in cutting 1/2" to 3/4" thick material, is down spiral and for all intents and purposes I cant see the difference in chip evacuation between the two.

I usually dont bother with these compression bits unless I am cutting Melamine, or G2S ply with a face veneer(s) on PC. If the spoilboard isnt too chewed up a downcut works almost as well or wood veneer. But for melamine these work wonderfully.

They sure cost more though. I use mainly Royce-Ayr (Canadian made) but have a lot of Onsrud bits as well. And a few other brands.

[Ger21]

A quick look around the web today showed 3+3 and 4+4 bits designed to cut at 1500ipm @ 40,000 rpm

On our Morbidelli, with a 3 flute compression bit, I cut at 1200ipm and 15,000 rpm.