I just don't get it....

[dougmsbbs]

My new model 'C' is STILL breaking cutting bits. The problems with the head going up and down are fixed, and it cuts real sweet. But, and it's a BIG but, I go through cutting bits like mad.
For the last two I was cutting through 1/4" birch plywood at .15" per pass using the 3/16" bit. Had the extra wood on the ends to stay under rollers. Head pressure is right at 84 pounds. Head is dead on level.
Does anyone have any ideas at all what else I could do different to save the cost of a new bit per project? Anyone? Anyone at all????
HELP!!!

Douglas

[Digitalwoodshop]

More than likely it is a Brass Roller problem....

Could the rubber spacer under the brass roller be missing?

Are you using masking tape?

Does the edge of the board have any defects or missing spots causing the brass roller to loose contact with the board?

Is the sand paper belt rolled under? Or are you using the rubber belts?

Are you using a carrier board?

Are your in feed or out feed tables adjusted too high? Raising the wood off the roller?

AL

[dougmsbbs]

All good suggestions, so I went out and took a good look.

I'm using a carrier board the same size as my work piece, 24" X 11", and a 1/2" thick. I screw the work piece down on it, making sure the heads don't stick up. It does not seem to have any defect on the bottom that I can see. I always use tape, so that's not it.

The rubber piece is in there, and the roller is very hard to press down. The rubber O ring is there and looks in good shape.

The machine has the new rubber belts.

Both feed tables are actually a bit low, but with a piece only 24" long I can't see that being a problem.

I'm telling you, six broken bits in two months is getting kind of expensive. Could it just be trying to move too fast?

[AskBud]

All good suggestions, so I went out and took a good look.

I'm using a carrier board the same size as my work piece, 24" X 11", and a 1/2" thick. I screw the work piece down on it, making sure the heads don't stick up. It does not seem to have any defect on the bottom that I can see. I always use tape, so that's not it.

The rubber piece is in there, and the roller is very hard to press down. The rubber O ring is there and looks in good shape.

The machine has the new rubber belts.

Both feed tables are actually a bit low, but with a piece only 24" long I can't see that being a problem.

I'm telling you, six broken bits in two months is getting kind of expensive. Could it just be trying to move too fast?
I suggest that you attach your MPC, A photo of your actual board (showing where the bit breaks), and a photo of your sled where we can see your screws (are your screws on the top or bottom?). we/I need to actually see where the bit is located when it breaks.

The "out rollers" should be adjusted even with the belt area. If not you end up with 18" or more extending past the pressure roller. This could allow the board to lift off the brass roller, which will cause the system to "fast-feed" the stock. A warped/bowed board/sled could cause the same effect.

Let's start there, and see what we have.
AskBud

[Digitalwoodshop]

I believe you may have hit the nail right on the head.... The Feed Rate is JUST TOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOOOOO FAST..
Did I get LHR's Attention.....

I believe that some times when the Cut Path Speed shifts from 1st gear to 2nd gear that is when the machine is pushing the bit faster than it can cut.... I found that when using the 1/16th end mill bit and the tags were pushed free from the 2 sided tape.

So here is what I would do.... I would lay down strips of scotch 3/4 inch double stick tape. Screw your wood down. Design your cut path without tabs as a outline and NOT a cut Path. Assign the 3/16 bit and get your layout correct and select the DEPTH. THEN Change the bit in Designer to the 1/4 inch Bull Nose and CHECK the DEPTH and still load the 3/16 bit..... This Action will lock the bit into 1st gear. Something I have been asking LHR to add to the Depth of Cut Window.... LOCK INTO 1ST GEAR..... That shift to the faster 2nd gear feed rate is TOOOOO Fast for some cutting.

AL

[lynnfrwd]

You got my attention, so I forwarded a link to this thread to "the powers that be"....

[dougmsbbs]

I headed out to take some pictures as Bud suggested, and got to thinking. It won't do us any good. This is not the same pattern time after time that I'm breaking bits on. It's anything and everything with a cut out. All woods, all thickness', and all cutting depth per pass. Never a problem with the carving bit, of course. I stay away from the edges, and make sure the boards aren't cupped or bowed or warped. I do understand I need to get those out feed trays leveled. I'll get that donw while I wait for my (seems like weekly!) bit order gets here.

I did notice when it was cutting it seemed to be zooming around at a pretty good clip. I'm really starting to think that's it. Cutting speed. I'm going to go with what Al said about locking it into low speed, when I get another bit, of course. I seem to be out, for some reason....

Al, do I understand correctly that you don't use any kind of tabs at all? Just the tape to hold the cut pieces down? I'd LOVE that if it works okay. Some of the stuff I cut has the tabs in places that are hard to sand and still get things looking right. Hands ain't as steady as they used to was. Hell, they never were are steady as they use to was...

As far as the 'powers that be' go, how hard can it be to add a check box that says 'low speed' up beside the other size, angle, etc boxes?

I hate to beg, but PLEASE! PLEASE! PLEASE!

Douglas

[liquidguitars]

Head pressure is right at 84 pounds.


how do you know this?

you are snapping 3/16 cut bits? using 1/4 ply? hmm.. a few quick tips on sleds as i not snaped a bit in a long time.

1. make your sled bottom using 3/4 thick wood.
2. never, never, never use a sled with 3.5" tails AWAYS use 4" or bigger.
3. do not center your sled in the machine. place the sled 4" tail under the board sensor once cranked down lift the long end to check for pressure every time you run the unit.
4. Make Designer and the sled the same or close to the same size including tails. " do not undersize Designers board just so it looks cool, but add everything in your sled.

[Alan Malmstrom]

I would check to see if the chuck is wobbling or the bit is still while it is spinning. A weird freekish thing like that would cause broken bits under a veriety of circumstances. Tape over the bit and a guage against it while you manually spin the chuck might work for checking that.

Alan

[Shacky]

The best scenario, in my opinion, would be to be able to set the rate in the design software as the designer would know such things as if the project was going to be done on hardwood or softwood.

[sdb986]

I just had an issue on a brand new machine with the 3/16th bit. I got to thinking about this....when I cut with the 1/8th, it cuts VERY slow. The speed that the 3/16th cuts is WAY too fast. It's causing undo bit stress. Can someone at LHR address this cut speed?

[AskBud]

I just had an issue on a brand new machine with the 3/16th bit. I got to thinking about this....when I cut with the 1/8th, it cuts VERY slow. The speed that the 3/16th cuts is WAY too fast. It's causing undo bit stress. Can someone at LHR address this cut speed?
Please explain further, and attach your MPC, so we may understand the source of the stress point. The MPC is important!
AskBud