I am carving a large letter Q in centerline with my 90 bit. It is a two part sign. the problem is the letter is carving full depth of the bit and it is pushing the capabilities of the machine. Is there any way to do the cut in two passes?ThanksJoe
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I am carving a large letter Q in centerline with my 90 bit. It is a two part sign. the problem is the letter is carving full depth of the bit and it is pushing the capabilities of the machine. Is there any way to do the cut in two passes?ThanksJoe
I had that a few times when I was Making my signs... I Extended the V90 bit about a 1/4 inch and just before it started cutting pushed the bit back in 1/4 inch and ran the job the first time, text only. Then ran it again without moving the bit for a full depth.
I also cleaned and touched up the bit with a diamond file first.
I am also a BIG FAN of bigger sign letters being cut with a 3/8 End Mill Bit... I pick a Single Stroke Font like Modern Text and select Outline Mode and the 3/8 bit goes around the text. As you make the letters bigger you need a bigger end mill bit that is a cutter with a cutting edge on the bottom. And smaller as you go down in size.
I do a .10 depth and it makes a nice painted sign. The Picture is Modern Text Font and Outline except the "the" that is Centerline.
AL
There was discussion at the last conference about cutouts and the use of multiple passes versus a single pass. We did not discuss Centerline, but I think the discussion is still applicable. Joe of LHR, who gave several of the tutorials, insists that they did much testing of the machine and its bits in all types of wood. Extensive testing. He recommends full-depth cuts in any wood. He said he does this all the time and has never broken a bit because of it. He did say he uses the appropriate bit for the job. I took that to mean that one should use the 3/16" cutout bit in hardwood rather than the 1/8" bit for example. Based on that discusion, I have switched from .25" pases to full-depth cutouts. Yes, the machine makes noise and the flex shaft sometimes vibrates, but the cutouts come out fine and no broken bits, so far so good.
Joe claims that with multiple passes stress is placed at the tip of the bit and makes it more likely to break due to bending action. With a full-depth cut, he says stress is uniform and better. Metallus has made the same recommendation.
For whatever it's worth.
And I've said it a time or ten...
Depth is determined by the thinness or thickness of the font. If the thickness is wider than the bit surface, then it will make a pass on either side (leaving an island in between).Quote:
Originally Posted by joepei
Attachment 78826
I tried another test piece with the Q set up in outline with the 90 bit and took multiple passes. It seemed to be a bit easier on the machine. The final cut depth is 3/8" deep. it seems to cause a lot more vibration depending on which direction the cutter is moving. The test pieces were MDF, I am going to try the cedar panels now. I also got a check motor stop half ways through this cut.
What is the condition of your bit?
AL
It was sharpened about 6 carvings ago. But those were in hardwoods. I will get sharpened and see if it makes a difference.