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will-munny
01-23-2010, 02:18 PM
Hello all, How many hours should the 1/16 carving bit last. I realize that there are lots of factors that would go into that, but, on average how often should i replace it. Thanks in advance.

GaryW
01-23-2010, 03:41 PM
Mine last about 100 hours, but I was using it to remove large areas befor I figured out that I could use the 1/8 for that.:rolleyes:

Jeff_Birt
01-23-2010, 04:57 PM
Hours is not a good way to measure bit life; you don't know how many of those hours were actually spent carving with the carving bit or through what type of wood. As a rule of thumb you should see about 50,000 linear inches in softer woods such as western red cedar. Using harder woods will of course shorten bit life.

Wilbur
01-23-2010, 05:47 PM
I am getting 200+ hr with mine. I use cedar and poplar only

Wilbur

PCW
01-23-2010, 06:23 PM
If I'm correct and using Jeff's estimate of 50,000 linear inches on soft wood the number I come up with 1s just a little over 130 feet of 12" stock.

Carving a 12" board and allowing for a 50% bit overlap. This number is if you where carving every inch of the board. About $.031 a sq. foot and if you don't break a bit.:mrgreen:

temler
01-23-2010, 07:00 PM
Hours is not a good way to measure bit life; you don't know how many of those hours were actually spent carving with the carving bit or through what type of wood. As a rule of thumb you should see about 50,000 linear inches in softer woods such as western red cedar. Using harder woods will of course shorten bit life.

how many lin inch do you think you get out of them if your carving mostly hard maple? this is another one of those overhead cost you need to add in if your making a sign for money. That is if you want to make money. ha
So for you great math people out there how many linear inches of cutting is there in a 12 by 12" raster carve? O one more thing it is being done on the best setting.
that should be fun
Thanks
Tim

JMD
01-23-2010, 07:10 PM
With A .005" Overlap It's 200 Passes Per Inch. 12 Inches Works Out To 2400 Passes Times 12 Inches Per Pas Comes Out To 28800 Linear Inches.
I Know Too Much Time With Nothing To Do.

temler
01-23-2010, 07:16 PM
With A .005" Overlap It's 200 Passes Per Inch. 12 Inches Works Out To 2400 Passes Times 12 Inches Per Pas Comes Out To 28800 Linear Inches.
I Know Too Much Time With Nothing To Do.

so that is telling me that if you only get 50,000 lin inch out of a bit you can only do two 12" X 12" raster cave is that right. or am i looking at this wrong. I know I know, too many pain killers again.

Thanks for the figures i could not remember the overlap.

JMD
01-23-2010, 07:27 PM
I Don't Think The 50000 Inch Figure Is Correct. A Little On The Short Side. I Would Go With 100000 To 150000. I Have Used Carbide Cutters, In Cnc Machining Centers, For As Long As 6 Hours Non Stop In Mild Steel.

Jeff_Birt
01-23-2010, 10:06 PM
The number I quoted is with the whole bit in contact with the wood, 360 deg engagement angle. (Generally that is how the manufacturer of the bits I carry tests them, but I will confirm that.) I should have also used the word 'minimum' with that number too. If you have a small step over then your not stressing the bits as much. Keeping the bit clean and cool (air blast) is a good way to extend its life.

If your using a bit until it is leaving burn marks or its tip is looking really mangled then you could be putting a lot of undo stress on your machine.

temler
01-24-2010, 07:07 AM
The number I quoted is with the whole bit in contact with the wood, 360 deg engagement angle. (Generally that is how the manufacturer of the bits I carry tests them, but I will confirm that.) I should have also used the word 'minimum' with that number too. If you have a small step over then your not stressing the bits as much. Keeping the bit clean and cool (air blast) is a good way to extend its life.

If your using a bit until it is leaving burn marks or its tip is looking really mangled then you could be putting a lot of undo stress on your machine.

So is there really a good way to know when the bit is getting dull. I know on hand routers you can feel it on how hard it is to push, you just get use to knowing the feel when it is getting time to replace but i just don't know how to decided to spend another 40 bucks. I do like the finish by Rick 4 flute carving bits better than the 3 flute, i don't know but maybe it is in my head.
does a 4 flute bit last longer than a 3? Is there any way to sharpen a carving bit??
My Llama head carved in maple take a good chunk out of the life of a bit. is there a way to check for a dull bit by looking, maybe under a microscope?
Thanks
Tim

dbfletcher
01-24-2010, 08:05 AM
Someone on the forum had mentioned in a another post that the leading edge of the carve also give health clues on the bit. I just switched to a new bit and I think there may be some merit in what they said. With the new bit the leading edge is very sharp, clean cut... with the bit i just replaced there was a lot of fuzz on the leading edge.

Hope that helps,

Doug Fletcher

CarverJerry
01-24-2010, 10:23 AM
Temler, you asked if these bit can be resharpened. These bits are carbide endmills and many machine shops either have a tool grinding dept or they source them out to a tool/cutter grinder. Im sure if you called any local machine shop they can point you to someone in your area that does tool/cutter grinding.