Cutting OSB...

[geneb]

I'm currently cutting some OSB (.47") with an Onsrud 52-910 cutter. My spindle is set for 12,000RPM and I'm cutting at 4in/sec.

I'm getting rough, "hairy" edges on the cuts. Is there any way to avoid this or is it just a characteristic of the material?

tnx.

g.

[jdoug5170]

Gene...we used to cut units of that stuff. Don't know the numbers anymore, but, we used insert cutters, probably at 18,000 and about the same travel speed as you are and yes, it is pretty rough. I don't think you can avoid it.

[harryball]

If the furries are mostly on the top edge, have you tried a compression spiral?

/RB

[jhicks]

Gene, may not be the answer but check the other (scrap side) of the cut. Is it better? If so change your cutting direction.

[tuck]

It's been my experience with OSB that I can't make a silk purse out of a sows ear.

[geneb]

I experimented a bit and kicking the speed up seemed to help a bit. 4in/sec seems to have cut way down on the furry cut problem.

I thought about buying a compression spiral, but it would be about 2x the cost of the project.


RB - Congrats on post #1000!


Mark, it's been my experience that people who make snarky, unrelated commentary to the question being asked are really annoying.


g.

[harryball]

Gene, check the prices of compression spirals at Centurion Tools. I think you might find the cost acceptable.

Thanks! I hit a milestone and didn't even notice... 1000+ posts!

/RB

[khaos]

There might be differences in board from different suppliers. At least I have found that in MDF. The type I get from Lowes is furry but the stuff from a different distributer is clean with the same bit and cut rate. They look and feel the same before cutting but after cutting you can really appreciate the better material. btw: The better material is cheaper in this case!!!

Mark Didawick actually pointed this out to me.

Now that I've said that ....
Joe.

[geneb]

The material I'm using is from Home Depot. Can't beat it for $5.98 a sheet, but man the company that makes it kills me with their thickness control.


I checked the thickness before I started my CAD drawings and it came out to .47. Of course, the sheet I actually fed to the 'bot came out to .43, so all the slots were loose. I'm not going to complain much, especially considering the cost of the material. Now if it was $30/sheet MDF, I'd be after someone's head.


g.

[link]

I have no experience in this area,(ShopBots) but...
Cutting "Good both sides" Oak Plywood I would make a very lite cut, 1/16 or less on the back.
This worked in this case. Here you might try it on the top.
Ralph

[geneb]

Ralph, if I was using regular plywood or MDF, I doubt I would have the thickness issues I'm running into. However, OSB is dirt cheap and does what I need it to do for this project.

My biggest recurring issue seems to be "thinking" in metal tolerances when working with wood. If I could just find 1/2" cast acrylic in 4'x8' sheets that cost $6, I'd have it made. *laughs*

Rob - I'll check Centurion out today and see what kind of trouble I can get into.

g.

[harryball]

Gene, I ran into a thickness issue with supplied material (I'll never do that again) and I ended up creating multiple tool paths.

I created a file for .230, .235, .240 and .245 which covered the ranges. It wasn't a very complicated project so the CAD time wasn't too awful. Anyway, I then measured the material before I loaded and selected the best toolpath for that sheet. The customer subsequently couldn't understand why he couldn't mix and match. Just can't make some folks happy.

/RB

[geneb]

Well fortunately, the only person I have to make happy is ME. Unfortunately, I'm a rotten customer and bitch constantly about the quality of work I get.


Here's what I've been cutting out of OSB:
http://www.simpits.org/~geneb/top_frames2.jpg

g.

[cnc_works]

Robert, you can imagine my chagrin when cutting 3/8" cast acrylic. Varies from .35" to .4" on the same sheet. So, just out of curiosity, did you measure the OSB in several places, including the middle?

I had to basically give up and tell my customer we would have to change design tolerances because of the variety of thicknesses on the same sheet.

Donn

[harryball]

I was cutting 3D puzzles in 1/4" hard board provided by the customer. Fortunately, the sheets were fairly consistent just not with each other. The fit didn't have to be perfect, but it couldn't be sloppy or not fit.

Gene is a tough customer to make happy though, very demanding on tollerances... I'd not want to work for him. ;-)

/RB

[geneb]

Donn - I only took a few measurements along the perimeter of the material. Considering what OSB is actually designed for, I really shouldn't be so shocked that the thickness from sheet to sheet varies so much.

RB - I'm very tolerant of people, it's the material I want to scream at. *laughs*

g.