Broken bits AGAIN

[Oldtrainerguy]

I need some good advice. Once again my (carvetight C)broke a cutting bit. The carve was good and there were no issues with the board. Half way thru the cut SNAP! Down the tubes went a brand new 3/16 th cutting bit. This is the 3rd bit to break in a month and it gettingxpensive and frustrating to say the least. Board tracked will measured well and there were no error messages. Using soft pine with no knots .75 thick. I am afraid to do any more projects because of this issue. Can someone please tell me what the heck is going on! The machine is clean and works well except for cutting. I have rubber tracking belts and using version 1.77 software

[mtylerfl]

Hello,

Very sorry to hear you're having problems. We do need more information before being able to offer meaningful help, though. This is the first I have heard of a 3/16" bit breaking. I've broken two 1/8th cutting bits in the last four years. The bits normally hold up very well. Any bit breakage "should" be a very rare occurrence. I doubt it has anything to do at all with your CarveTight chuck. Something is definitely going on there that we just don't know about yet. Rather than starting a guessing game right now, let's go with the basics and eliminate the simple stuff first...

Are you able to post your MPC of this particular project? If so, we can look at your design settings and eliminate any possible issues there. Also, once we see the MPC, we will know how long the board needs to be to stay under the rollers and confirm with you that the correct length (or sled or jig) was used.

[dbfletcher]

The first and most obvious question is "were your following the 7" (or more) rule."?

[gregsolano]

I am having the same problem. I got my CW less than a month ago and two 1/8 bits already. I have reduced the cut pass depths to 160 and can see no other problems except the bit broke. On the last broken bit It carved one of the same project with no problem, on the second one the bit broke. I have gone through all this forum, planed my boards, reduced the depth per pass, checked and lubed everything. I am on my third bit and praying. oh and I built a sled to ensure the 7 inch rule.

[Digitalwoodshop]

Well this can happen when the board looses contact with the brass roller and drives the board in a jerk that snaps the bit. Masking Tape on the board to let the Brass Roller have something to bite into... If the roller slips on the pine then SNAP....

OR the board is coming out from under the roller and popping UP causing the bit to SNAP.....
What is the measurement from where the bit broke and the front of the Board. If exactly 3.5 inches then this is your problem..... 3.5 inches from Roller to Bit... Board comes out from under Roller and Lifts and SNAP....

Is the board being held down by both rollers all the time...

Other Things....

Bad Power Supply L2 causing intermittent drive.
Bad FFC Cable and the Z is not moving properly.
Dust in the Y or Z Encoder
Sawdust in the X Gearbox or a partially broken tooth.

OR.... CUT FEED RATE IS TOOOOOOOOOOOOOO FAST...... Spinning bit cannot cut fast enough to clear the wood and the servo is always ahead of the cut wood putting pressure on the cut snapping the bit. I saw this using a 1/16 end mill and the Y skipped a TOOTH as the bit was not cutting away the material fast enough.... It Clicked the Y Gear a Tooth.... I used double stick tape to hold my plastic tag to the carrier board. The Bit pushed the plastic sideways on the tape... Or clicked a tooth... Fixed it by assigning the 1/4 inch ball nose and using the 1/16 End Mill Bit so the FEED RATE Stayed in First gear..... I bet your bit snaps when the feed rate shifts into 2nd gear.... 1st gear on curves and 2nd everywhere else.

You Can't do that trick with a Cut Path... I have Requested that locking the feed rate in a Cut Path be included in a Designer Upgrade using the depth of cut window.

Good Luck,

AL

[gregsolano]

Sorry I meant 0.160 was my cut pass depth not 160 . I read in several places that people commonly use 0.200.

[CarverJerry]

I have purchased 1/8" bits from this guy, his prices are good and so are his bits.....Great Deal....
From eBay seller qualityprices_123
1-933N-001A 1/8" x 3/4"flute length x 2-1/4"oal 4 Flute square ends (flat bottom) $5.81 each
1-933N-002A 1/8" x 1"flute length x 3"oal 4 Flute Square ends (flat bottom) $8.69 each
or this is a current sale he has going http://cgi.ebay.com/10-PCS-1-8-4-FLUTE-SE-CARBIDE-END-MILLS-USA-/190486727828?pt=LH_DefaultDomain_0&hash=item2c59e4cc94
you can email them and they will find you exactly what you are looking for.

CJ

[mwhatch]

CarverJerry, how do you ue those 1/8th bits in the CarveTight spindle.
Thanks

[Oldtrainerguy]

I will post the MPC this evening. board was plenty big enough. Staying under the rollers, did not come out and was not warpped in anyway. The board had the extra length it was supposed to although it may have been exactly 3.5. Will check for dust on the X gearbox. What should the cut path depth be set at per path for a .75 board thickness.

[Alan Malmstrom]

I'm awaiting the delivery of my CarveWright machine now but the cut path depth sounds interesting to me being new to this stuff. I'm interested in hearing about this subject too. When does one encounter the ability to ajust this cut path depth. When you upload to the USB card perhaps?

[Kenm810]

On most Hard Woods I used .125" for the depth giving me 6 Passes,
on Softer Woods I used .200 or .250 that gives me 4 and 3 Passes.

No burnt project boards or broken Bits yet --- and no stair stepping problems
with multiple passes for Cut-Outs -- so far. And it adds only a few minutes to the carve time

[lynnfrwd]

I'm no hardware tech, but my first thought was power fluctuation.

[Digitalwoodshop]

I'm awaiting the delivery of my CarveWright machine now but the cut path depth sounds interesting to me being new to this stuff. I'm interested in hearing about this subject too. When does one encounter the ability to adjust this cut path depth. When you upload to the USB card perhaps?

Alan,

If you have not... Read all the Tips and Tricks... That will help you with all the Pilot Errors we see posted over and over. Any problem you will have with the machine will have already been posted and answered many times here and the real important stuff is made into tips and tricks. Understanding the machine is half the battle. You will get more enjoyment with your machine when on a Sunday afternoon you crank the head up TOO HIGH and it only clicks when you try to lower it.... It's in the Manual and Tips and Tricks but if you searched you would find that question posted a few times.... "My head is all the way up and it will not lower???"

We are here to answer any question you have as we ALL asked the same questions before Tips and Tricks.... We all started out asking the same questions. Tips and Tricks has helped the new users as it was developed to provide the answers before the question gets asked.

I am NOW a Wiz at fixing the machine.... In the Beginning my first machine made 2 trips to Texas before I mastered the repairs... So we all started at post one.......

Good Luck to ALL,

AL who

[Oldtrainerguy]

Here is the attachment of the project that broke my cutting bit.
Sorry its been a looooong week!

42867

[Digitalwoodshop]

Measure the distance from the snapped bit to the length wise edge of the board.

Let us know.... 3.5 inches then the board came out from under the rollers.

AL

[AskBud]

Here is the attachment of the project that broke my cutting bit.
Sorry its been a looooong week!

42867
42870
The grid, above, is .5".
AskBud

OTG,
My thought is this:
If your actual board is 10" wide, as shown in your design, you may be having the problem due to the top edge being cut too close to the keyboard. The Brass Roller may be losing contact which will allow/force the wood to travel rapidly along the X-path until the roller makes contact again.

In many cases it would be nice to know the exact point of the breakage, however, I don't know that it's necessary in this instance.

I would bet the using a wider board, and centering your project would also solve your breakage. The other option would be to assure that the cut-out, on the top, is further from the edge.
AskBud

[Oldtrainerguy]

Thanks Bud. I also checked my cut depth which was at the default and that too may have contributed. Th bit broke at about the half way point on the top it made the turn cut a little more and snap.

[badger2424]

I'm awaiting the delivery of my CarveWright machine now but the cut path depth sounds interesting to me being new to this stuff. I'm interested in hearing about this subject too. When does one encounter the ability to ajust this cut path depth. When you upload to the USB card perhaps?

Alan the cut path depth is adjustable when you select the cut path to cut out whatever pattern you're cutting out. But like Al said, make sure you read and reread the tips and tricks and any other info you can find on this site to learn all you can. Knowledge is the main ingredient when working with the CW, you can't have enough. It's what makes the machine work!

[badger2424]

Oldtrain, I always set my depth to .125, like Ken said, it takes a little longer but I've no broken bits yet-cherry, oak etc and it works fine, even through knots. Hope that helps. Also like Al said, make sure you use the masking tape if you're not, I think it is a must. Al, seems like everything I say, I have to say "Like Al said". Like to have all your knowledge, you wouldn't write it down would you?

[Oldtrainerguy]

Thanks to all who have replied. I think the problems were two fold.
1. The little brass roller was not staying seated on the edge of the board (fixed with masking tape ) Thanks AL
2. Cutting depth was set too deep so when roller lost contact snap!
Since using masking tape and setting cut depth shallower no more snap-a-doodle

[Digitalwoodshop]

Good JOB !!!!!

AL