2 broken bits in 1 week

[DianMayfield]

I have had (2) 1/8 cutting bits break this week. Both were new, still in bubble wrap from LHR.

Bit 1 I was cutting 2 layers of MDF Bead board on a sled - depth .35" - about 1/2 hour of cutting time on new bit - actually broke in board, causing an x-axis error
Bit 2 I was cutting 1/2" MDF - about 2 hrs cutting above boards, 15 min cutting 1/2".

716457164671647

Anyone else having issues with LHR bits?

What should I be looking at if it is an issue with the machine?
Thanks in advance!

[fwharris]

I would suspect some type of tracking issue or the depth of cut per pass. Where you doing these as full depth cuts or did you set a max pass? Where you cutting these on a sled and did you have masking tape on the bottom edge of the board that runs on the brass roller?

Also double check your head pressure.

[DianMayfield]

The bead board was on a sled, and yes, the 1/2 & .35 depths were single depth/pass carves. No masking tape, these boards are pretty darn straight and have not had problems in the past- registration between different cuts of same project is good.

I had 80 hrs of similar cuts on my last bit. Anything over 1/2" I do 2 passes.

Using a pretty expensive bathroom scale, I can see 10 lb differences over 5 tries. Is this normal? 75-85lbs.

[Digitalwoodshop]

With all that glue... I would do multi pass cutting...

Would love to see your sled and a picture of the bottom. Do you have masking tape on the bottom of the brass roller end of the bottom of the sled?

Looking at the picture and no appearent going off track, I believe the bit is just over whelmed with the 2nd gear feed rate.... The feed rate is being pushed faster than the bit can clear the glue wood chips.

I would consider shifting the cutout to milti cut, or select a bigger bit but load the 1/8th and that will lock the feed rate into 1st gear. I don't see any tabs so you are using tape to hold the loose pieces? Since that is the case?, you could tell the machine you have a 1/4 inch bit loaded but use the 1/8th.

Another cheaper option.... use Circuit Board Bits and a Roto Zip chuck that will hold the 1/8th inch shaft bits. They even make them in bigger cutters like 1/8th inch... DON'T even think of using Roto ZIP Bits... they are too soft and will BEND.... Ask me how I know....?.

You can find the Circuit Board bits on eBay. Just had a thought.... With the CT you will need a 1/2 inch bit holder.... to hold the 1/8th bits.

AL

Edit: In after thought, I know LHR would likely not endorse the use of circuit board bits.

A few problems you would encounter using them with the CT would be the length. If you told the machine you had a 1/8 inch CT bit, the machine is going to expect the length to be withing a tight standard. We saw this with the upgraded Designer changes when all of a sudden the Rock Chuck 1/8 inch bits would CRASH... Either BEND down the Bit Plate being too long or if too short get a load bit please message. Once we tuned the Rock Bit Length to MATCH the CT Bit all was well... So if you adventure on the dark side and go with the cheap circuit board bits... you will need to get the length correct.

Next, you will need a 1/2 inch holder... Sounds like a job for RON to make a 1/2 inch Chuck Shaft to hold the 1/8 inch shaft Circuit Board Bits. Since most have a Rubber Stop.... If Ron got the length correct it could be a very cost effective cutting system.

And lastly you will need to be sure the cutting bit length the actual cutting area is long enough to cut your board.... Most Circuit Board bits are pretty short... See that box I got, it has some 1/8th inch cutters in it... I also won that auction the other day and got 10 Circuit Board bits for about $6.00 with shipping. It's the size I use for Tags.

Good Luck,

AL

[DianMayfield]

Hi Al,

I will look into collets, that other small cnc machine that no longer exists used to sell them.

I was going to try the 1/4 in fake out, but I do not have that bit in my options. 3/16th or 1/2. I will try the 3/16 with an offset.

I have attached images of the back of the two boards that broke bits. The one with tape is my sled, the one in front of the other cut ones is the 1/2 in MDF. Neither has tracking wheel marks, although I have seen them on pine and oak before. Image name is 1.5 but it is really .5"


Head pressure about 75lbs.

[CW-HAL9000]

[QUOTE=DianMayfield;234412]Hi Al,

I was going to try the 1/4 in fake out, but I do not have that bit in my options. 3/16th or 1/2. I will try the 3/16 with an offset.
/QUOTE]

You may have an older version of designer (older than 1.87) If you upgrade (free) you may then have the 1/4 bit option.

[DianMayfield]

"bout as close to 3.0 without paying 200 bucks.... 2.007

[Digitalwoodshop]

I am confused... so you are setting up vector lines and selecting the bit and the depth (along with multi pass cutting)? It is my guess that any cutting bit bigger than 1/8th of an inch will give you 1st gear feed rate but I really have no clue as I don't have 2.xx.

Select your bit and give us a screen shot of your options? I don't believe you will need a offset... Setup the artwork with the smaller bit then select all and select the new bit and set depth and multi pass and save. I believe the machine will cut the same path reguardless of bit size... I could be wrong...


AL

[bergerud]

Hi Al,

I will look into collets, that other small cnc machine that no longer exists used to sell them.



Look at

http://www.ebay.com/itm/New-1pcs-1-2-ER11-28L-Straight-collet-chuck-and-3pcs-ER11-collet-1-4-3-16and1-8-/281142871145?pt=BI_Tool_Work_Holding&hash=item41756

[fwharris]

Look at

http://www.ebay.com/itm/New-1pcs-1-2-ER11-28L-Straight-collet-chuck-and-3pcs-ER11-collet-1-4-3-16and1-8-/281142871145?pt=BI_Tool_Work_Holding&hash=item41756

Would these work in the CarveTight chuck??

[bergerud]

Would these work in the CarveTight chuck??

Yes, that is what they were designed for. I believe about 80 of them have been sold to CW users so far.

[fwharris]

Thanks, guess I missed that post or did not read it correctly.

[Digitalwoodshop]

With a short circuit board bit, I wonder if it would be long enough to match the 1/8 inch CT length bits? Pretty Slick.... I like it.

But if it did not match the CT 1/8th length it would only matter if you wanted to do a cut path. If you lie to the machine doing a vector and use a 1/16th or 1/8th circuit board bit and tell the machine you have a 1/4 inch it should work. Even in a ROCK.

[bergerud]

With a short circuit board bit, I wonder if it would be long enough to match the 1/8 inch CT length bits? Pretty Slick.... I like it.


The ER11M adapter gets right down to the board just like the Rock. I use those short bits all the time.

I guess you guys missed the memo on this.

(It is buried in a 132 post thread! http://forum.carvewright.com/showthread.php?22633-ER11-Adapter-for-the-CT&p=208380#post208380 )

[Capt Bruce]

Count me among that 10% too like Floyd that just never get The Word. Ahhh so many memos missed and no time to go back and read them all.

[Digitalwoodshop]

Thanks, yes, missed the memo too and it was hiding in plain sight...

Thanks for the link.

Looks good too...

AL

[DianMayfield]

Sorry to take so long to get back, Dutch Oven competition took over the past few days. Too many hobbies :)

Anyway, I have attached images of my two bit lists - one from inside the cut path selection, the other in the select bit list. No 1/4in.

Secondarily, if I select the 3/16th bit, the project time is 5 seconds faster with the 3/16 bit vs 1/8th. That's on two 12*8 cutouts. I would imagine that this means the machine will not run slower with the wider bit fake out.

Still concerned that I had 80hrs on the last cutting bit, and got less than 4 total on two new bits.

[FWMiller]

I think you'd need to make the machine think it's cutting with a smaller bit. Smaller bits see more fragile so they cut slower. I have used the ER11 adaptor and it works great. For 1/8" cutouts that go no more than half an inch I use an inexpensive solid carbide router bit. It has 1/4" shank tapered down with a 5/8" cut length at 1/8" diameter. Much stronger than a 1+" length bit like the standard cutting bit. I really have to mess up big to break this bit. I still don't cut more than .25" outer pass and usually only go 1/8" per pass.

[Digitalwoodshop]

The Tricking the machine WILL NOT work using a cut path. You must use the bits as called for in the list for a proper cut. The delema is that the cut path uses a 2 speed or 2 feed rates to cut and the faster cut will sometimes snap a bit especially when you add the glue in the board. A multi pass cut will solve your problem.

I setup a vector line or rectangle and then pick a bit like the 1/16th end mill and do my artwork. I then change the bit in designer to 1/4 inch. But I still use the 1/16th end mill to do the cut. Since NO TABS are setup, I use double stick tape to hold the loose parts. IF you FAIL to hold the loose parts with no tabs you will damage the machine and snap bits.

Multi pass cut path will solve your problem as it leaves tabs. I don't want to use tabs as my plastic will fracture at the tab making a defect tag.

AL

[DianMayfield]

Make that three.

30 SECONDS into the CUT, the bit broke. So I am apparently missing a potential cause. Any and all feedback would be greatly appreciated on what might be out of whack in the machine.

Using tape
Tried the short bit as recommended, got a z axis stall so I switched back to the LHR bit, figured I would work on the short bit/collet issue later when I am not under the gun. Turned off the machine, turned back on and measured the board in both directions with no problem.
On a 1/2 sled with .123" pressboard material. 1/8in bit.

Possibly related:
http://forum.carvewright.com/showthread.php?26263-x-gears-presume-teeth-broken Replaced gear
http://forum.carvewright.com/showthread.php?26155-Z-Roller-Bearing-loose Replaced bearings

$40 dollar project now well over $200 in cost...arghhh. About an RCH away from being done with this- I had fun once, didn't look a thing like this.

[Digitalwoodshop]

Sorry to hear you broke the bit.... and sorry the short bit did not work out....

First... Were you doing a multi pass cut path? How deep? IF you have another 1/8th inch bit I would run the same project again... This time as the bit gets ready to actually cut.. STOP THE MACHINE by pressing STOP Once.... Open the cover and REMOVE THE BIT.... Now start up the machine again and watch the machine like a hawk and see if you see any jerky movements?

Now lets talk about the small bits.... It's all about the bit length.... The reason the Z Stalled is that the small bit was likely installed TOO LONG and it touched the bit plate or more likely SMASHED into the Bit Plate before the Z Motor Current Sensing was turned on. With the latest Designer the machine is tuned to the length of the LHR 1/8 inch CT Bit and it is tuned to a VERY NARROW window of length that will work.... TOO Long a NON LHR CT BIT and the bit Smashes into the bit plate IGNORING the Higher Current as the Current Sensor is NOT turned on YET... IF you make the Bit SHORTER by trial and error you can find a length that works... I DID... Now if you get the bit TOO SHORT then the bit will not touch when it expects to touch with the current sensor on and will give you a message LOAD BIT.... As it thinks NO Bit is present.... So it is a Trial and Error Game to get it right... I use the metal Locking Rings on my bits and getting a 1/2 inch version should be easy... You will need one for each ER11 to lock that length you insert it into the CT... I would buy more than one ER11 and have one for each size bit... so you won't need to adjust the Ring and have jams.... KNOW that the Z STALL forced DOWN the bit plate and it may be bent down...

Good Luck,

AL

[bergerud]

It seems to me that you have a tracking problem. Stay away from the 1/8" cutting bits until you have figured out what is wrong with the tracking.

Unfortunately, x tracking during cutting is much more sensitive to machine condition than tracking during carving is. Belts can creep on the rollers if the head pressure is too high. The board can slip on the belts if the head pressure is too low. Sandpaper belts can roll up. Rubber belts can rub on the brass roller. The x drive system can be jammed up with sawdust. The x gears can have too much backlash. The list goes on.

It is very difficult for members of the forum to trouble shoot x tracking. The more information you can give, the better. Otherwise, all we can do is start down the list.

I think the most common reason for bad tracking on a rubber belt machine is the front rubber belt rubbing on the brass roller O ring. Push the brass roller down (like the board would) and check the clearance between it and the belt.

[DianMayfield]

New development.

Got the short bit in and it cut for about 5 minutes. Watched closely. As the bit went to the next shape, the motor stopped just as it started the plunge, and the bit drug through the wood. Then got a z stall.

I would imagine that if it had been the 1" bit, it would have snapped at that point.

Say... I will be in Vancouver for work in late October... Beautiful up there!

[bergerud]

That does not sound like a tracking problem at all. Probably something simple llike the right cover switch. Do you have a DC holding up the cover?

[Digitalwoodshop]

Sounds like the right side cover switch too... Like above... Dust hood... ? Could be on the fine line to cover closed and need to look at that... Adjust if possible.

Next.... how many cut motor hours? Over 250 you should change the brushes. LHR CB 001 (Carbon Brush 001) They last about 280 +- but when they get short they won't let the motor start.

Inspect the X Termination Board under the machine. Look at the C1 Capacitor, it should have glue in the old days they would vibrate and snap off. It is part of the cut motor on off switch. Look for burnt copper and parts.

GLAD you got the cheaper small bits working. LESS STRESS over snapping one...

AL

[DianMayfield]

AL,

LHR is out of brushes - Israel says they are looking for a new source.

157/170 Cut Motor/Servo hrs - My brushes look to be about half way between what your photos show. There are a couple of small motor repair shops in town, I was going to see what they could do for me.

We will go looking at those connections... you have an impressive library of photos!!

Thanks so much.

We do have a DC on there, the plastic one from Irwin products.

[lynnfrwd]

Make sure you did not cut too little away on your cover. Vibration can make it lift, if it isn't cut away enough causing a stall that will break your bit.

[DianMayfield]

I did tape down the lid a little while ago (put a seat belt on it :) ), same thing, about 5 minutes in it stopped. We cut it out straight, so it rests on the DC. Been running that way for 125 hrs, so maybe some wear/slop issues.

[bergerud]

Try running the cut motor test routine. You can wiggle stuff around while the motor runs and maybe discover the reason the motor quits.

[DianMayfield]

Well, this is turning into one big mess.

Ran the Cut Motor test. Ran for a few seconds, then stopped - but it says the motor is running (liar liar, pants on fire - if you do not laugh, you will scream) The second and third test, nothing happens, just the message that the motor is running.

That being said, like many others on this forum, I get the Check Cut Motor each first carve that the machine is turned on for (second and third carves don't get the message). Have gotten that message since hour 42 or so. So I am guessing that it is stuck in that first carve of the day loop.

Time to call LHR.

[bergerud]

It could be that you have a poor connection in the cut motor. Small clips which attach wires to the brushes can be fickle. Did you try tapping the motor during the test? (I know you want to hit it!)

[SteveNelson46]

You could also remove the cut motor and connect it directly to 120V to see if it runs. I have used this method a couple of times and it helps to isolate the problem. Just need to make sure the motor doesn't jump off of the table when the power is applied.

[DianMayfield]

Thanks gentlemen,

Hitting it didn't solve the problem - but it DID feel good :)

Do you know if you can remove the cover of the machine, leaving the cover switch connector attached while it is off to the side? Will the machine run with it off? Sure would make all this testing easier. Although, I may try the direct to motor connection if there isn't anything obviously bad or loose.

[bergerud]

You have to disconnect the cover wires on the keypad side so it is not easy to run the machine with the cover off. You could, however, connect external wires to the motor (an old lamp cord for example) without taking the motor out.

[Digitalwoodshop]

With two people, have one hold both the safety switches in while you do the cut motor test. It would be easier to feel if the switch released with a finger. See if the motor will start. Could be that you need to cut a little more off the clear cover. Also inspect for switch damage. When ever you remove the top black cover and move it, you need to be aware that the clear cover rests on both cover switches. A future design might include a mechanical stop on the clear cover to prevent it from resting on the switches. I only have "A" machines so the "B" or "C" might have a mechanical stop. What I am getting at is it could be possible that the Right side Cut Motor Return Circuit switch has been damaged. Either by moving a black cover around or by cutting TOO MUCH off the clear cover... Support the clear cover when the black cover is removed.

So by holding the switches with fingers you half split the troubleshooting.

More of what has already been posted above....

It can be the X Termination board or a loose wire on the board.

The Crimp Push On connectors between the cut motor and X Termination Board have been known to come LOOSE and have been known to have WEAK CRIMPS as in where the wire is crimped to conector.

Since you removed the brushes and they are 1/2 the length I would stay with them for now... IF you really feel the need to replace them I will send you a LHR set on loan and you can send me a set when LHR gets them back in stock. At 150 hours they are still GOOD in my opinion...

So in my opinion it is going to come down to the right side cover switch that is either bad or the cover is not activating it. The Finger push with 2 people will tell us more....

So the wires on the Cut Motor can be confusing but here is the easy way to remember the wires...

Cut Motor has a Black Wire and a White Wire. The X Termination Board cable has a Black Wire and a White Wire. The right Cover Switch has a Black Wire and a White Wire...

The Black Motor Wire connects to the Black X Termination Wire.

The White Motor Wire connects to EITHER WIRE of the Switch, it's just in and out of the Switch. The Other Switch Wire either Black or White connects to the X Termination board White Wire... The purpose of the Switch it to prevent the Cut Motor from operating with the cover open.... Woooo... Long winded but you may need a quick review...

My phone number is on my website below, I got 2 calls the other day from Texas, a guy fixing a head level problem... Was happy to help... eMail is digitalwoodshop at AOL dot com...

I don't worry too much about spam... Won 2 Lottery's this week and a package is waiting for me in Chicago with 5 million dollars in it... :)

AL

[SteveNelson46]

I don't worry too much about spam... Won 2 Lottery's this week and a package is waiting for me in Chicago with 5 million dollars in it... :)

AL

If you believe that I have some beach front property to sell you here in Arizona.

[DianMayfield]

Hi Al, this is Dian's husband, Butch. Thank you for all the help you have been giving her. I've read over the responses she's received and they have been very helpful.
This evening we checked the X termination board and all looked good; Dian took some photos. Next we check the cover switch. It has two switches but there is no wiring to the left switch and its plunger is all the way in. The right switch clicked before the cover was all the way closed... probably 1/4" at the cover edge. It felt and sounded good. We took the cover off, moved it over to the side and connected the switch and probe sensor leads and taped the cover "down". We took the drive cable and housing off so that the cut motor would be running alone.
We performed a "cut motor" test I believe it was called, numerous times. The results varied somewhat. Sometimes the motor started, others it did not. When it didn't start, a tap or two or three, on the housing with a screwdriver handle started it. Sometimes it stayed running, others it only ran for a few seconds, or five or ten, then tap, start, stop, tap, start, stop. No pattern seemed apparent. Every time it ran the speed was "surging". I back probed both leads into the motor. It showed a pretty steady 65 volts (to ground) from before the test started and did not vary much, if at all, even when the motor started or stopped. Meaning it stayed 65V when the motor stopped, tap start stop etc. I'm guessing they vary the voltage to control speed and this is the setting for the test. I checked the amps with an amp meter and they swung between 2.4 and 3.4 and varied with the surging. Looking through the vent slots I could see a very minor amount of sparking from the brush area that would vary with the speed surges. We wiggled the speed sensor wires and all wiring and connectors under the top cover and none had any affect on the surging. When the motor stopped and showed voltage we wiggled all wires and the motor did not restart. It only restarted when tapped. Dian checked the display and each time it stopped the display showed it was still running.
I pulled the brushes and they looked ok, not beat up or chipped. They are about 1/4" in length and the upper looks to be worn at a slight angle. The outer end of the brush assembly (clip, retainer, guide?) was about even with the motor outer case and had to be pushed in to get the cover to start screwing in. The lower had a bit of carbon dust come out with the brush. The armature does not appear to be abnormally scored and the ends of the brushes looked evenly worn where they contact the armature. We blew out the motor with canned air through the vent ports and got a little saw dust and a little carbon dust. We put the motor back in a ran the test again... no change. Any ideas? We are leaning towards something in the motor based on the tap tap to start situation. Thanks

[Digitalwoodshop]

If you believe that I have some beach front property to sell you here in Arizona.

The Real Estate Agent told me that California is going to drop off into the Ocean so buy QUICK.... Will have a great view... LOL....

Good Luck with your switch test... After the switch test next look over the X Termination board. Be sure to un plug machine with the bottom cover off.... Both the Power Supply, X Termination Board and even the ON OFF Switch have 115 Volts AC on them... Careful... No Shocks allowed....

AL

[bergerud]

I think the fact that hitting the motor makes it restart means that the problem is a physical connection inside the motor. As I said before, the clip connections to the brushes are a prime suspect. Take the motor apart and see if one of them is discolored from heat.

[Digitalwoodshop]

Butch,

Excellent Troubleshooting Post... Lots of GOOD Detail....

It is possible that the Teather or the Carbon Brush inner copper wire if shorter on one brush as the tapping and running is a classic... "The Brush is too short". Like posted above, it could be a loose connection inside the motor.... You could remove the motor from the machine and open it but it is a risk since you can have a wire snap or when you put it back together have a wire out of position and a spinning part hit the wire... I have had good luck opening the motor cases about 4 times... the 5th... I snapped a wire off and as seen by the wire with the yellow arrow, I had a wire hit a moving part.... With all that being said... You could open the motor and inspect it. You will find a screw inside the muffler hole that eluded me the first time.

Send me a email through my website or digitalwoodshop at Aol.com with your address and I will get a set of brushes off to you tomorrow on loan. My thinking NOW is that it IS a Short Brush... One Teather may be shorter than normal....

AL

[DianMayfield]

Al, the mailing address should be on its way via the "contact us" on your website. Thank you.

I visited the area motor shops this morning to see if I could find the brushes locally... no luck.
I will tear into the motor in the morning most likely. Just got home from a long day with a mellon ache and the motrin hasn't kicked in yet. May get into it later tonight.
I was thinking, and wonder if the brushes being worn at an angle, as the two in your photo DSC01461 are, could be allowing/causing the brushes to lean over a bit and cause them to hang up in the slot. Maybe not fully but enough to unload the contact surface and cause a poor connection with the commutator segments on the armature. That could explain why the tapping helps. When the motor is running I'm sure the brushes bounce a slight amount and may be hanging up from time to time causing the motor to stop.
Thanks again

[lynnfrwd]

Told we should have some carbon brushes next week. Haven't tried these yet. Fingers crossed.
May be a short in cut motor and just needs rebuild.

[Digitalwoodshop]

Brush angle... GOOD Catch... It could cause binding.... No contact message yet? Leaving for the Post Office now... Monday...

AL

[DianMayfield]

Update.

Got the brushes, thanks AL. Installed them, first time in 100 hrs I didn't get that darn CCM message, worth the price of admission there! LHR said yesterday that they expect a shipment sometime after next Friday - something about holidays in China.

Got the y axis error about 10 minutes into a cut. Loaded a small carve to see if I got any further. Carved for about 10 minutes, got the stall.

Hubbie bypassed the cover switch with a jumper to eliminate that as the cause, no change. Reloaded the carve to watch it this time. Only went for about 3 minutes and it got real quite...I walked over and the head was bouncing happily along thinking it was carving, but the motor had stopped. I am sure glad those carving bits are stouter than the cutting ones :) Could tap on the motor and it would run for a few seconds (removed the bit so that stoutness wouldn't be tested any further).

Butch is now into it with a multimeter, the epitome of dogged.

There are motors in stock, the new versions, which are supposed to be quieter. I am more than a little ticked off that I need to consider a rebuild - 2 weeks total time with shipping - after 160 hrs, or a new motor.

[bergerud]

Why do you not take the motor apart and look for the bad connection?

[Digitalwoodshop]

WOW... that is not good.... Sure sounds like the motor is the fault not the crimp connectors to the motor...

Glad the brushes arrived.

AL

[DianMayfield]

Update Part Deux;

CAUTION - not to be tried if you do not have solid electrical experience and damage to internal motor wiring can occur without due caution!

Butch had tightened up the connectors inside the motor last week , a couple pulled out pretty easily.

Last night, while doing the resistance measurements, one side of the windings indicated high resistance when the female end (pulled out of the holder) was wiggled in a certain manner. He could feel a "ticking", and when the ticking was felt the resistance went up. He presumed a broken wire in the first winding loop.

Since I had already decided to buy a new motor, he was going to remove one loop of wire from the winding and reattach the connector, see if it would work. In the pictures below,

Insulated portion containing a fuse, presume an overload,
The copper wire connections to the fuse - note the tight loop on the left, and the open loop on the right
The right connection had evidence of arcing - note the copper bead on the fuse loop and the thin spot on the wire loop
See close up of the thinning wire loop.
Brushes - ours were almost exactly 1/2 of the original size - I suspect that there is still life in them, as the wire is more suspect in the intermittent motor issues.

He cut the wire at the thin spot and made a tighter loop over the right fuse loop. Carved and cut this morning with no further issues.

I cannot express enough how much I appreciate the folks on the forum. It's not just the information or ideas for solving problems, it is the fact that we gain confidence based on their past successes (or failures :))

[Digitalwoodshop]

GOOD JOB to you BOTH.... GREAT Pictures too...

AL