v-inlay technique problems

[scottp55]

Having a Small flat on the bit won't make that much difference...Most of my VInlays were done with an Onsrud .25"shank 60degree engraving bit with a .01" flat defined as a VBit in the toolpath, they came out fine.
I agree with Brady...looks like something is loose/binding somewhere.
scott

p.s. Why the offset in the Male?

Oh...JUST saw on Vectric forum that you're using an offset vector as a boundary box

[bking1836]

Ok....So I think the gantry sits on the X axis tightly. And the spindle doesn't budge. When I yank on the yz car from the side by pulling near its bottom, it is tight. But when I yank on the yz car from the side by pulling near the top (by the plastic cable car), which is closest to the rack and pinion, I think there's a little bit of slop. At least it's the only place I've yanked on the machine and felt movement.

So what does that mean? Thanks so much for your help!

BTW, beautiful inlays Scott. That's what I am hoping for!

[phil_o]

Turn the control box on and wiggle the living daylights out of it in ALL DIRECTIONS. Grab the spindle force it by hand up and down. Front and back. Left and right. Feel or hear slop? Find it. Same with the X/gantry @ EACH side. Same with the YZ car.

Have a PRS? Check the lower v-roller bearings. Remove the black covers and adjust...not too tight...not too loose.

-B

After reading this advice for checking for slop I performed this test on my machine. I have a 12 year old PRT benchtop. When I push on the gantry that travels in the X direction I have some noticeable slop, about .02" measured with a dial indicator. How much slop is acceptable, what is the fix?

[bking1836]

Well, I think I have my answer. After tugging on the machine more I can't say I feel much of any slop. So I cut a bunch of squares defining the 60 degree bit's geometry differently for each of them, and they ALL had the same extra scooping out at the corners. So I looked at the bit more carefully and see now that it's probably rounding at the tip. Then I ran the original v inlay pocket toolpath using a newer 90 degree v bit, and presto, sharp corners.

IMG_0392.jpg

Is it possible that my z zero plate is contributing to the dulling/rouding of v bits?? I cringe every time I watch that point hit the metal plate...

Thanks everyone.
Brian

[steve_g]

Brian…

I know for a fact that I’ve broken the tip of a 30° v-bit while z-zeroing… a 30° bit is a lot more fragile than a 60° bit though.

What I do:

I loosely hold up one end of the plate a bit while the zeroing procedure does its rapid “down” move and then let it lie flat for the second, slower touch. I haven’t had any issues, even with 30° bits using this procedure.

Talking bits… my experience with 60° bits is that the CMT laser point 3 flute bit is unsurpassed in in quality and reliability. It comes to a true point that is dead on concentric. Also, I think that the 3 flute design gives better support to the fragile tip. I’m sure others will dispute or say they have a better solution, but this is my experience…

SG

[kaetamer]

You might try using brass as your zeroing material. Tough to imagine brass dulling or breaking carbide tips...