MDF "eating" bits

[wesday]

In 6 years of cutting 1000s of sheets of 1/2" mdf I have never had this problem. I cut 1/2" mdf only, with Belin 3/16" spiral O bits only. The last load of mdf is just "chewing" up my bits. I initally thought I might have gotten a bad batch of bits. So I put in a used bit that I knew was ok and the same thing happened. I tried a different brand of bit, same thing...So I assume the mdf (from my same supplier as always) is EXTRA hard and abrasive. The cutting edge of the bits are just solid little chip marks. Has anyone else had this happen??? I am cutting EXACTLY the same as I have for years. Usually I can cut from 15 to 30 sheets before changing bits and even at that there is no chipping on the bit, just a dull bit.

[bleeth]

Wes:
There are basically two classifications of MDF. One is "Virgin MDF" (like Trupan) which, at least for now, is made from all new trees and the other is "recycle" which has at least some percentage made from reground wood product, which unfortunately may include incidently ground up foreign matter which often includes the remains of fasteners. Naturally the ground up fasteners are real bit eaters. It would not surprise me to find out that the brand of MDF you are using has now either started using more regrind or is being produced in a different plant than previously which does not have as sophisticated a filter system as your previously purchased product. It is unfortunate, that when it comes to the wood products we all use, the quality of the raw product seems to be regularly decreasing as time goes on.

Dave

[wesday]

Hello Dave,

I have been getting my supply from a local small lumberyard chain. They give me a great price and keep several bundles in stock for me. That way I don't have to warehouse it. I am sure they probably get it from whoever gives them the best deal at the time. Maybe the next load will be back to normal....

[harryball]

Dave is correct, you probably have a bad batch with metal or too much glue resin etc... I've quit using Plum Creek after the last few sheets if 1/2 material I purchased. I can't tell you what was wrong but the stuff fuzzed like I'd never seen before. I thought my bit was dull. All three of the sheets I'd purchased felt like furry crushed velvet after cutting with any bit. The partial sheet of the same stuff I had left over cut just fine. I don't know what was different, but it was different.

Robert

[elcruisr]

Every time I use something besides Trupan I end up going back to it. Luckily I have a good supplier of it nearby. The foreign matter problem gets really bad in particle board. After a really bad load of bit eaters I contacted my wholesaler. I was informed that particle board standards allowed 5% metal content by volume, wonderful....

[harryball]

I've had partical board that set off my metal detector. It'd all be clear but one little area would make it chirp. I figured it was a ground up fastener. I don't want to argue, but I think it may have been .5%, 5% sounds way too high. Either way, that's still too much when it comes into contact with carbide. Maybe a good arguement to use hss bits on this stuff.

Robert

[fleinbach]

I no longer purchase from Chesapeake Plywood in Baltimore since the last batch I recievd from them was terrible. When cut it was extremely fuzzy. It was also very weak. I had several pieces dropped on the shop floor literally break in half. I called them and complained. I asked if I could bring it back to exchange for some better boards. They told me it was from the same supplier they always used and all of it was the same. I then asked for a refund on the remaining sheets so I could purchase something I could use. They said they do not give refunds.

As I said above I will never purchase from them again.

[elcruisr]

R Ball, after cutting one sheet that trashed a cutter (of course new) and starting a fire (let's hear it for those fire extinguishers) I bitched at GP and was informed that they allowed 5% metal content, not .5%!

[harryball]

Wow... that's a lot of metal. That's 4 lbs in an 80 lb sheet... that's almost a 5 lb box of nails.

Robert

[elcruisr]

Yeah, seems to me like it's another industry spec that allows them to get away with pretty much anything and still be "in spec". I know of one guy who hit a solid spoon in particle board! There's got to be a story there.....

I won't even get started on what I think of the current plywood standards though!

[harryball]

I think this topic has strayed some, the moral of the story for the OP is to choose your materials more carefully and be aware quality varies even within product lines. Don't forget to suspect bad material, not just bad bits.

Nancy the form goddess may zap me for being off topic... your "spoon in particle board" reminds me of a toilet brush I found hanging on a fiber optic circuit in the telco facility of a major named circuit provider. You have to wonder what is going on that allows stuff like this to happen. The facility manager covered up the incident... which sort of answers the question of how and why it happens.

It seems all down the line employees care less and materials are of less quality. Instead of doing something about it the "industry" redefines the standards to allow it.

I was told by GP that I was using their BCX plywood incorrectly by running it on the bot. I think the exact words were "you are not using it for the intended purpose" I still have several sheets of the stuff and it will not go flat, it was glued with a bow in it and is a good 1/4" out of square. The B side on several have more filler putty than wood and enough footballs to play in the NFL.

I hate to hear stories like yours. It's OK to grind up 4 lbs of nails into each sheet of particle board. That's just not right.

Not being able to return substandard materials isn't right either. So long as no consequences are felt back up the industry line I fear quality will continue to suffer more and more.

Robert

[terryd]

Robert,
I've hit bullets in my pine from the lumber mills, and it has destroyed planer, molder and saw blades worth thousands. Who gets the bill? The mill laughs and said "better you than me". The person responsible of course is a hunter with lousy aim. Two morals, first the most guilty party is usually the furthest from the scene and second don't assume that you supplier will ever hold your interest above theirs. Like boxing, protect yourself at all times.

[harryball]

Terry, I agree that natural or inherent hazards exist, but you can hardly compare allowing scrap metal to be ground up into a manufactured product rather than removing it to a bullet buried in a tree.

I'm not talking about unavoidable or unforseen problems like buried bullets in natural products. I'm speaking more to poor manufacturing practices on manufactured goods. So long as distributors continue to accept substandard materials and dealers then pass them along to us and no backflow of defective products occurs, nothing changes.

Any dealer that laughed at me for any reason would no longer be my dealer. I've returned defective materials occasionally and have always reached an acceptable agreement. In one case the dealer appeared shocked at the quality of the sheet goods and pulled the entire stock off the shelves returning it to the distributor. They changed brands after that and I still work with that dealer.

Finally, I've never tried to hold a dealer responsible for destroyed bits or blades... these in my mind are a hazard of the business and why I own a metal detector.

Robert

[gene]

I also have had mdf to fuzz like crazy when i get it from the big orange box store . There are several grades of mdf and i went back to my origional supplier that cost more but the quality was definately better... At the depo it is around 20.00 at my supplier around 27.oo and well worth the extra. as far as bullets the onlt i have ever found was bird shot in some pine .