last straw for me

[Pratyeka]

Well I should have known better than to try carving a 17hrs project into .75" red oak on ultimate setting. The project was to be a pharao's head in three slices .74" deep carve in a 36" by 14.5" red oak board. Brand new 1/16" carving bit with TiN coating. 1/3 into the carving, I heard the machine stop. One look and I see the carving bit has turned black, the smell of slightly burnt wood, and the Y axis stall message...

Am I asking too much from this machine? Is pine and cedar the hardest this machine can reliably carve for long projects? 5 hrs and a brand new TiN plated carving bit is burned???

[dbfletcher]

Pratyeka,

Not to change the subject.. but aren't you the one who is building their own 3 axis carver based on plans from the internet?

If so, is there a website you are using to document your progress? I would love to follow that project and someday down the road I plan on attempting it myself.

Also, I think it was on Jeff Birts website then the TN coating does extend the life... but it also slighly dulls the bit from the get go too... so you end up with a longest lasting slightly dull bit that a brand new super sharp uncoated bit. If you want to see the link, I'll dig it up again.

Thanks,

Doug Fletcher

Edit: My bad. Jeff talks about ZrN - Zirconium nitride coating on his website. Here is that link: http://soigeneris.com/glossary.aspx

[eromran]

Pratyeka,

Not to change the subject.. but aren't you the one who is building their own 3 axis carver based on plans from the internet?

If so, is there a website you are using to document your progress? I would love to follow that project and someday down the road I plan on attempting it myself.

Also, I think it was on Jeff Birts website then the TN coating does extend the life... but it also slighly dulls the bit from the get go too... so you end up with a longest lasting slightly dull bit that a brand new super sharp uncoated bit. If you want to see the link, I'll dig it up again.

Thanks,

Doug Fletcher

Edit: My bad. Jeff talks about ZrN - Zirconium nitride coating on his website. Here is that link: http://soigeneris.com/glossary.aspxIf you are wanting to build your own GOOGLE "joe's 4x4 hybrid" you will be amazed what you can build for 2000 lots of info simalar to shopbot but you build it your self then it buildes the next one !!!

[dbfletcher]

I'll will look that up.. but i could have sworn I've seen posts for buidling a fully functional 24x48 3 axis machine in the range of $700-$1000.

Doug Fletcher

[eromran]

I'll will look that up.. but i could have sworn I've seen posts for buidling a fully functional 24x48 3 axis machine in the range of $700-$1000.

Doug FletcherI wasn't saying you could not build one cheaper but look what 2 gets you. No kind of machining or welding ether

[unitedcases]

I remember one time when I started getting that smell as well. The RPM sensor was acting up and I probably had a dull bit. Rons bits are 4 fluted but if you do the easy off oven trick then usually there isnt any built up pitch. I only respond because the only projects that I do are 4 and 5 hours long and I only carve in red oak. I do stop every hour to vacuum just because I am not as advanced as everyone else.

[liquidguitars]

I noticed some burning 2, version 1.153, could be the raster bit is coming in a little hot and moving y a millisecond to soon after the plunge. However i not a big fan of the aftermarket bits and at this point i like the stock 1/16 LHR bit better more carbide to chuck with cut less burning.


TiN coating

He is going to run in the same issues with a home built that is if he can get his raster algorithm to copy the carvewright system. Not sure if the TiN coating has any negative impact as far as wood go. Jeff B could have some idea why one would choose plasma coating " better for plastic?" as he offers this option on his store.

Also something to think about is if your bit is a 4 flute of 3 flute and the length of the cutter and it's taper..

LG

[Rick P]

Pratyeka,
...back to your original post ... I would guess the coating was the culprit in your project. I have carved in red oak for over 6 hours with the original CW bit with no problems. I like the carving bit from Ron Justice even better.

When I worked at 3M we were always looking for "coatings" to extend life of injection molding machine parts. We never found any that would last long enough to be worth the added cost. Selecting the type of base metal and part design were the best ways to extend life. We were running abrasive materials through the molding machines...wood acts like an abrasive on the bits.

[Pratyeka]

The last 2 bits that burned were bought from Jeff. I mentioned TiN because that's what I remember, but not sure. They have that gold look. At $40 each, I would expect them to last at least 100 hours, in any wood. As such, they are not worth the price. I test the sharpness of each bit as I receive them, fingernail test. Now they wont even bite into the fingernail, dull as a butterknife.

Building my own CNC, yes, check my blog, link in my signature.

[SteveEJ]

Pratyeka,

You need to fix your blog link.. Add a '.ca' before '/blog' and it works..

BTW.. The CNC is looking real good!

[Jeff_Birt]

The ZrN (zirconium nitride) coating will provide a better bit life, the harder the material the more it helps. Testing in ebony revealed a 2x or better improvement. The regular uncoated bit has an anticipated life of 50,000 INCHES in western red cedar. Harder material are of course harder on the bit. It should be noted that any bits have to be cared for: they need to be cleaned of pitch after each use and must be protected when in storage. Carbide is brittle and will chip if banged into other bits.

You cannot directly translate the number of hours used on the CW machine to bit life. Bit life is a function of the amount of material cut and the type of material, how hot the bit runs, and bit care. I'm not sure what the average feed rate of the CW is when carving as it slows a bit the deeper it carves. Guessing at a conservative 20 IPM that yields 1200 Inches an hour. So you divide the 50,000 inch anticipated bit life by 1200 and you get just under 42 hours. That is in western red cedar. Hopefully that gives folks an idea of how to judge bit life.

Smoking/burning are from a dull bit. If the bit is getting dull before its time then one of the things to look for is overheating. Overheating can be from a combination of excessive runout, aftermarket chuck not allowing proper heat transfer from bit, too aggressive feed rate, improper spindle speed, running for too long at a time in hard materials, etc. It could also be the case where the optimal carving setting does not remove enough material with each pass. The chips carry aways heat, taking too small a bite is akin to the bit just rubbing on the material and generating more heat than chips. (I don't know on that last one, I'll ask CarveWright.)

My guess would be that the OP has a heat problem. Since wood is so variable, the density and moister content can be all over the place. Too high a moisture content will tent to gum up bits and blades more quickly. I've run both the original carving bits and the PreciseBits carving bits for hours on end in all sorts of hardwoods. I still use the QuickChange, not known for its minimal run-out, but I did add on a small air-blast tube right after I first got the machine, and a down draft not too long after. With the air blast I have never had a bit get very warm.

[Pratyeka]

Both bits were burned during long carve with ultimate mode. During the last one, I check the temp on cable, Z-truck, spindle and bit using infra-red thermometer, the hottest spot was the spindle running at 40C. The dust collector intake sits at about 1.5" from the bit and sucks in enough air to cool everything down.
I stongly suspect the feed rate on ultimate to be too slow for red oak when carving at .750" depth.

I wish there would be a dry lubricant that could be sprayed on the bit as it is carving.

Also, thanks Steve for the head's up on my signature. It's fixed now.

[Jeff_Birt]

Wood will not burn or smoke at 40C (104F). I could not find an exact reference for the temperature at which wood will start to burn and smoke but do know that a wood burning tool will heat to 600~900F. (Infrared thermometers can be wildly inaccurate depending on their quality, the distance to and reflectivity of target.) Obviously with the condition of the wood and bit you were seeing it was getting quite a bit hotter.

I'll see if I can get some info on the feed rate for 'Optimal'.

[Pratyeka]

I use instruments that a regularly calibrated at work. I could not of course make the instrument "see" only the cutting edge of the bit. The field of vision included also the wood and the shank of the bit. Anyway, suffice to say I'm not wasting anymore bits in this machine.

[liquidguitars]

Seems to me that you are overlooking the fact that you are using a 3rd party bit not the LHR's 1/16 carving bit designed for the CW it's bigger with more surface to chuck up.

I got a new bit from Ron that started to burn right away I replaced it with a old LHR 1/16 carving bit and little to no burning but like jeff saild it could be the wood i was running.

I am wondering if it's the design of the aftermarket bit not the CW.. :mrgreen:

LG

[Jeff_Birt]

LG, the PreciseBits carving bits are the same size as the OEM CW bits, they ARE NOT the short bits you are describing. I have yet to hear of a problem from using them.

[liquidguitars]

Right, I was talking about the "shorty" I got from Ron and Ebay " did not mention Precise bits" I was wondering about the size and flute count of the bit not the vendor.

Its my assumptions that the "shorty" and flute count 4? could have something to do with the burning but it just a guess on my part.

Good to know about precise bits i got a "shorty" 1/16" carving bit from them last year. I have seen on their website that the bit where longer than before??? , but not all bits out in the carvewright world are the same size. I have one new shorty "2" and one new LHR OEM 1/16" carving bit I test them and see if i get any burning.

What the overall size they sell now?

If it's not the carbide it's the firmware, Back to my impression on raster, the bit comes in a little hot and moves to the right in y a little fast at the start then seems fine.



LG

[Pratyeka]

LG, the PreciseBits carving bits are the same size as the OEM CW bits, they ARE NOT the short bits you are describing. I have yet to hear of a problem from using them.
How come the two bits I ordered from you last summer were short (1" shank)?

[Jeff_Birt]

Take a look at the entire tool length. Sometime early last year the PreciseBits carving tools had the DOC increased a little to one inch, given that it is a two inch long bit that leaves 1" for the shank. That bit is the same overall length and the flat is in the same spot proportionally as the CW bit. Since the DOC is a little longer (it was made to match the original machine specs of a 1" deep carve) the shank will look shorter.

The bits LG is talking about are perhaps 1.5" long.

[Wilbur]

I have to say one thing. The carving bit that came with my machine last a lot longer than the one I got from Ron. Using this one last less than 100 hr where the one that came with the machine last for about 300 carving the same type wood. Cedar an Poplar.

I have 418 hr of run time.

I found that I started having problems with axis stall and found that it was because of dull bits.

my machine is gone now to Sears for repair and looking for it back any day. I have bought three new bits from Northern and waiting to see how they work.

After I ordered them I found I could have gotten them from Amazon for 10.00 less, per bit, same bits. I think

Wilbur

[liquidguitars]

I ran a new "shorty" aftermarket 1/16 carving bit today cutting raster in softmape and the bit became dull in about 16 hrs or less, that's bad and could be due to a few things like having 4 flutes, The tip got black and the carving suffered as a result. I like to send it back if i could but i run some more tests if i can. Looks like the shorty could be better for plastic and ebony, but not soft Maple.

For my money I would use LHR 1/16 carving bit all the way. ;) Ebay you can get the LHR OEM bit with free shipping.

I did notice that the bit adapters are now glued to the bit with red locktight thats what I did back in the day but using Blue 204.


LG

[Steven Alford]

The last 2 bits that burned were bought from Jeff. I mentioned TiN because that's what I remember, but not sure. They have that gold look. At $40 each, I would expect them to last at least 100 hours, in any wood. As such, they are not worth the price. I test the sharpness of each bit as I receive them, fingernail test. Now they wont even bite into the fingernail, dull as a butterknife.

Building my own CNC, yes, check my blog, link in my signature.

This is the same for me. I got my bits direct from Jeff and also two direct from PreciseBit (they are 20 miles from me). They advertise that they will last 2 to 3 times longer. But they do not. They in fact last less then the OEM. I use mostly red oak and soft maple. This said, they are still a very good bit. The carve quality is very good. They just don't last as long as they advertise and at $40 each, I would rather buy the OEM from LHR.

[Pratyeka]

Thanks LG and Steven, at least this proves I'm not hallucinating.
It's probably due to the wrong feed rate for that particular bit, being 4 flutes. Too bad the CW won't let you adjust the feed rate. My CNC will be completed soon, so that should fix that.