Chuck Keysor
02-17-2013, 12:19 AM
Hello Shopbot Community. Can anyone give me some suggestions as to what is going wrong with the carvings that are shown in the attached pictures? The cuts I got with a CMT "Laser" V bit were very good. I had used the CMT bit for many hours before running this test.
The cuts I got with a Precision Bits 60 degree engraving bit were not good at all. The Precision Bit had never been used before. The attached photos should make the comparison and my situation clear.
Also, I am not blaming the bit for my problem. I am assuming I have messed something up, but I don't know what.
I bought a brand new collet from Shopbot before I ran this test on the Precision Bit. I ran the two test tiles one right after the other.
I programmed the CMT bit as a V-bit in Aspire, and the results were quite consistant with what I have had for the last year, quite good. (The second CMT test cut, was done using "depth of cut" limiting in Aspire. That result, as I have had before, wasn't so good, but I did that one test for documentation only.)
The first Precision Bit cut was programmed in Aspire to be a regular 60 degree V bit, and I did normal V carving. The resulting grooves were really wide, even though the tip of the bit was clearly sharp enough to have made lines as fine as I had asked for in my Aspire design, and had gotten with the CMT bit.
The second Precision Bit was programmed in Aspire as an engraving bit, with a .005" flat on the end of the tip. The results were no different from the first Precision Bit test, at least by checking by eye.
Background: I get great final results by using a CMT "laser" 60 degree bit carving in Vinyl Composite Tile (1 foot square kitchen floor tiles). They have no grain, lay dead flat, very uniform in thickness and hold great detail. BUT, the grooves, after cutting, are totally plugged with gunk, not remeltd really, but gunk. Re-routing does almost nothing to remove this gunk. It won't brush out. I must carefully scrape it out with an Xacto knife, which takes as long as the carving (which I do at 1 to 1 1/2 IPS). This is mind numbing work that I can no longer stand. Since the CMT laser bits don't have any spiral to help clean out the grooves, I looked for a bit with a spiraled flute, and found the Precision Bit EM2E8-0625-60VC, 60 degree engraving bit with a .005" tip flat.
The first two shots simply show the fully cut test tiles. In the second picture, I physically laid the two tiles next to each other to show the dramatically different results I got between the two bits. The top CMT cuts are amazingly crisp. In the third picture, I am making a direct comparison of the details of the bird carvings, again the CMT results are excellent.
Any suggestions? Thanks, Chuck
The cuts I got with a Precision Bits 60 degree engraving bit were not good at all. The Precision Bit had never been used before. The attached photos should make the comparison and my situation clear.
Also, I am not blaming the bit for my problem. I am assuming I have messed something up, but I don't know what.
I bought a brand new collet from Shopbot before I ran this test on the Precision Bit. I ran the two test tiles one right after the other.
I programmed the CMT bit as a V-bit in Aspire, and the results were quite consistant with what I have had for the last year, quite good. (The second CMT test cut, was done using "depth of cut" limiting in Aspire. That result, as I have had before, wasn't so good, but I did that one test for documentation only.)
The first Precision Bit cut was programmed in Aspire to be a regular 60 degree V bit, and I did normal V carving. The resulting grooves were really wide, even though the tip of the bit was clearly sharp enough to have made lines as fine as I had asked for in my Aspire design, and had gotten with the CMT bit.
The second Precision Bit was programmed in Aspire as an engraving bit, with a .005" flat on the end of the tip. The results were no different from the first Precision Bit test, at least by checking by eye.
Background: I get great final results by using a CMT "laser" 60 degree bit carving in Vinyl Composite Tile (1 foot square kitchen floor tiles). They have no grain, lay dead flat, very uniform in thickness and hold great detail. BUT, the grooves, after cutting, are totally plugged with gunk, not remeltd really, but gunk. Re-routing does almost nothing to remove this gunk. It won't brush out. I must carefully scrape it out with an Xacto knife, which takes as long as the carving (which I do at 1 to 1 1/2 IPS). This is mind numbing work that I can no longer stand. Since the CMT laser bits don't have any spiral to help clean out the grooves, I looked for a bit with a spiraled flute, and found the Precision Bit EM2E8-0625-60VC, 60 degree engraving bit with a .005" tip flat.
The first two shots simply show the fully cut test tiles. In the second picture, I physically laid the two tiles next to each other to show the dramatically different results I got between the two bits. The top CMT cuts are amazingly crisp. In the third picture, I am making a direct comparison of the details of the bird carvings, again the CMT results are excellent.
Any suggestions? Thanks, Chuck