What's up with this new bit?

[zan29]

Can someone tell me why my new 1/16" bit (3 carves only) does this? No, I didn't drop it or anything like that, carved pine and birch that's it. Tried my old one and don't have those results, it's carving properly except for all the nice little curls.
Am I entitled to a credit or a new one ? :rolleyes:;)

[lynnfrwd]

Why is it not in the text area? Wasn't that also carved with the same bit?

[zan29]

I have no idea Lynn.........why I'm asking!

[bergerud]

I do not think that it could be the bit. Something else must be going on. Post the mpc?

[SteveNelson46]

I do not think that it could be the bit. Something else must be going on. Post the mpc?

I'm with Bergerud. It's not very likely the bit would carve differently in different areas unless it was instructed by the software to do it. Maybe two patterns super-imposed on top of one another and merged? A .mpc would help.

[peep]

Same thing that happened to me last week here http://forum.carvewright.com/showthread.php?25061-Anyone-know-why-this-happened it was a new bit too, but I can not possible see why a bit would do it.

[SteveNelson46]

Same thing that happened to me last week here http://forum.carvewright.com/showthread.php?25061-Anyone-know-why-this-happened it was a new bit too, but I can not possible see why a bit would do it.

Peep,

A little off topic but, I just did a lookup of your GPS co-ordinates. How is life in Belize?

[bergerud]

Zan, maybe something like the z truck belt is loose. Maybe the new bit pulls down on the truck and there is some slack which gives. Check for z slop or backlash.

[zan29]

The pattern is nothing complicated. 2 little bathroom signs for a restaurant. Tried to different simple carves with my new bit with the same weird results. Finished this carved with my old bit and it's fine. I have checked everything, the belt and the bearings are all brand new. I can't believe it's the bit either but it sure looks that way.

[zan29]

And my cutout was right on also!

[lynnfrwd]

That little boy & little girl are images (or patterns)? It has to be elements that are inherent to the pattern itself.

[zan29]

Yes the 2 signs are pictures but the other one I tried was a pattern from CNC mini projects.


That little boy & little girl are images (or patterns)? It has to be elements that are inherent to the pattern itself.

[lynnfrwd]

Yes the 2 signs are pictures but the other one I tried was a pattern from CNC mini projects.

Which other one?

[peep]

Steve, Belize is fantastic when I am here (build a winter home) although I have a 40lb wild hamster that is giving my garden an issue. The hard wood here is to die for.

[SteveNelson46]

Steve, Belize is fantastic when I am here (build a winter home) although I have a 40lb wild hamster that is giving my garden an issue. The hard wood here is to die for.

Is your "wild hamster" a Capybara or is it really a hamster?

I am envious of your hard wood supply. Probably pretty cheap too.

[bergerud]

I have checked everything, the belt and the bearings are all brand new. I can't believe it's the bit either but it sure looks that way.

New but loose? Check the carriage bearings. Maybe one is loose.

[lynnfrwd]

That little boy & little girl are images (or patterns)? It has to be elements that are inherent to the pattern itself.


Zan: If it is an image, can you take it into pattern editor and see if it is part of the image?

[zan29]

Lynn, it's not part of the image, I carved them with my old bit today and there's no lines whatsoever and they came out nice. The other one was the wine bottle from the mini projects.


Zan: If it is an image, can you take it into pattern editor and see if it is part of the image?

[fwharris]

How about a picture of the bit? With the bit in the chuck is there any play/movement?

[zan29]

Here's a picture of the wine glass and bottle. Started to carve with the new and than switched to the old one but could not get the exact height since I had removed the shank previously but you can see there is a problem. There is no play or movement but feels like a tiny tiny piece of metal came off on the tip.


How about a picture of the bit? With the bit in the chuck is there any play/movement?

[fwharris]

If you can feel a distinct difference between the two bit tips then probably one of the flutes on the end got chipped. Have a real good magnifying glass to get a real good look at it?

[SteveNelson46]

If you can feel a distinct difference between the two bit tips then probably one of the flutes on the end got chipped. Have a real good magnifying glass to get a real good look at it?

Unless the bit breaks during the carve it won't cause a difference in depth. Even then, the remainder of the carving will be at a constant depth. If it is broken from the beginning it may not produce a very smooth carve but, the entire area will be the same depth. So, the possibilities are (but, not limited to):

Logic error in the firmware
Loose or frozen bearing on the z truck
Z belt is excessively worn
dirty rails
power supply voltage fluctuation
controller issues
electronic parts damaged by static discharge

I am inclined to believe the same as Bergerud. It's a machine or software issue and not the bit.

EDIT: If you are switching to the long 1/16" bit it may be applying just enough extra resistance to a weak or damaged electronic component to cause the problem.

[fwharris]

Unless the bit breaks during the carve it won't cause a difference in depth. Even then, the remainder of the carving will be at a constant depth. If it is broken from the beginning it may not produce a very smooth carve but, the entire area will be the same depth. So, the possibilities are (but, not limited to):

Logic error in the firmware
Loose or frozen bearing on the z truck
Z belt is excessively worn
dirty rails
power supply voltage fluctuation
controller issues

I am inclined to believe the same as Bergerud. It's a machine or software issue and not the bit.

Steve,

I was just responding to her comments about the "but feels like a tiny tiny piece of metal came off on the tip."

I would not rule those as possible areas but I believe she also said she has carved this and other projects with another old bit and these lines/scrapes did not show up.

[SteveNelson46]

Sorry Floyd. I wasn't questioning your answer. I just replied to the wrong thread.

[SteveNelson46]

Another question. Are you using stop collars? If so, are they set at the same distance from the tip of the bit?

[fwharris]

Sorry Floyd. I wasn't questioning your answer. I just replied to the wrong thread.

No problemo! ;)

[zan29]

It cannot be the machine or software issue since the machine works fine with a different bit. I was comparing the two tips last night and the new one feels way too sharp, scratched my finger. There is no height issue, the reason why is because I changed bit and just eyeballed the shank. How did this happen?? I haven't got a clue.

[bergerud]

Different bits produce different forces on the machine. If, for example, the new bit has a tighter helix, there will be more of a force to "screw" into the board. The new bit pulls into the board more than the old one. Either the board lifted up or some slack in the machine allowed the truck to be pulled down. That is my theory.

[SteveNelson46]

It cannot be the machine or software issue since the machine works fine with a different bit. I was comparing the two tips last night and the new one feels way too sharp, scratched my finger. There is no height issue, the reason why is because I changed bit and just eyeballed the shank. How did this happen?? I haven't got a clue.-

Maybe it's the electronic circuitry in the bit.

[200k]

This is a long shot but, is there a possibility that the new bit has a slightly loose swaged-on collar that only shows up as a problem when it's cutting deep? You probably wouldn't be able to tell with finger forces alone. Can you try that bit in another machine on the same project and then a different project? For that matter, does this new bit have the same problem with a different mpc file?

200k

[DocWheeler]

Since the area where the word "Toilet" is carved correctly, and some of the deeper carving is correct, the fault would seem to be depth specific.
See if there is a small buildup on a rail that the truck sometimes "jumps" to produce a deeper carve while at other times just pushes against it.

Any slop in the Z would allow the encoder to get to the correct position while the bit would be positioned to whichever side of the bump the truck is stuck.

After looking at it again I have to amend this - there must be several bumps as there are at least two different depths with problems.

[zan29]

There are no bumps on the patterns and images I've used. Like I said, I carved the same patterns with 2 different old bits and they came out fine. I was looking at it closer today and it's not a piece of metal missing, it's actually sticking out. I will remove the shank and try it on my other machine.

[DocWheeler]

The "bumps" I was talking about would be on the Z rails or truck-bearings, not the patterns.

[zan29]

If there were bumps it would do the same with my other bits right?? No bumps anywhere.

[DocWheeler]

Assuming that the bits extended the same length, yes it would.
In thinking about what I'd do first to determine the problem, I'd use the ruined board for a test.

I'd make a zero-depth region over what has been carved and restart the carving.
But, this time I'd have it touch the board on a 1/8" to 1/4" shim so the carve would be shallower.
Carve an inch or so at this shallower depth and stop the test.
If the carve was without the "bad lines", redo (double-carve) it then without the shim for height.
Using the same mpc, recarve the area that was carved shallow plus another inch or so.
If the "bad lines" appeared in the double-carved area then the problem is depth-related, probably buildup on rail.
If it carved successfully this time it would indicate that the bit was probably pulling it down as Dan suggested.
If the carve had the "bad lines" with less stock being removed, it would indicate something was happening when the Z-truck was at that depth.
And, if the lines were not there in the double-carved area but reappeared while carving full-depth, it is bit related.

Just thoughts about what I'd test.

[SteveNelson46]

zan29,

Check the pressed on sleeve to make sure it isn't slipping on the shaft of the bit. I had a brand new bit from Carvewright slip and ruin the project once. You may not be able to move it with just hand pressure so it may be difficult to determine if it is slipping back and forth while in use. Also, we are all assuming you are using the standard CT chuck.

FYI: You cannot have a bit that is too sharp. The sharper the better.

[SteveNelson46]

It cannot be the machine or software issue since the machine works fine with a different bit. I was comparing the two tips last night and the new one feels way too sharp, scratched my finger. There is no height issue, the reason why is because I changed bit and just eyeballed the shank. How did this happen?? I haven't got a clue.

I'm not sure what you mean when you "just eyeballed the shaft". Did you actually hold the old bit and the new bit parallel to each other and compare the lengths from the sleeve to the tip of the bit?

[zan29]

It's actually that little piece sticking out that's pulling the bit down. The tip is suppose to be rounded like all other ballnoses, it shouldn't scratch my finger. Anyway, I will try it today on a different machine see what happens.

[bergerud]

Can you post a clear, close up picture of the tip? I do not think the tip could pull the bit down. It would be the sides of the bit that would do that.

[SteveNelson46]

It's actually that little piece sticking out that's pulling the bit down. The tip is suppose to be rounded like all other ballnoses, it shouldn't scratch my finger. Anyway, I will try it today on a different machine see what happens.

Use a magnifying glass or a jeweler's loop to inspect the tip. If it is deformed and you are absolutely sure it didn't strike something metal in the wood while carving (mounting screw, nail, staple, etc.) send it back to Carvewright before the 30 day warrantee expires. I'm pretty sure they will replace it as long as there is no evidence of it striking something that the bit wasn't intended to cut.

[zan29]

I've tried taking a better picture but my phone is limited and it's been more than 30 days I'm afraid for the warrantee .

[zan29]

Caught it the act. Could it be the traction belt??