firstshot425 wrote:Hey Adrian
Thanks for your reply. I use a CNC Router Parts Auto Z and corner finding touch plate to set Z-Zero and X / Y Zero. Also, I surfaced the wood prior to cutting. I get the bits possibly not being exactly as described and can see how that would make a difference.
firstshot425 wrote:Ted & martin54
I will definitely check out the process for verifying the bit angle.
I know you can't see it very well in the actual vcarve carving (Pic4), but I took a very close look at the actual carving and there doesn't appear to be any paint bleed. I put on 2 coats of shellac before doing the cut.
Putting on the shellac before cutting will not seal the cut areas. Think about it, the cut areas are exposing end grain which is notorious for slurping up finishes. You need to seal after you cut.
Also, there are no areas are NO black areas where there hasn't been any carving done at all. Everything with black has been cut.
I may have found the problem though. I took a caliper and as best as I could measured the depth of a bunch of the cuts taking into consideration some areas may have been sanded more than others. I found cuts in the lower left that were right around .015 but also found areas in the middle and top right which measured up to .08. So, obviously, it was cutting deeper in some areas than in others. I did surface the wood prior to cutting but only surfaced one side.
I do that quite often, it does not cause a problem. As long as the piece remained clamped where you surfaced it the top side will remain flat. Now, if you did not use clamps and instead used double sided tape, or clamps that apply force to the edge of the board all bets are off. Some guys seem to think that wedging a piece against a stop works. That is usually true for something like plywood unless they are using an upcut bit and discover that the bit is lifting the piece.
The bottom side was not surfaced at all and when I placed it on our granite counter top it did not sit flat at all. It rocked back and forth.
You said you flattened the top and then did the engraving? Did you do something in between? Like unclamp the piece? When you do work like this, you should surface on the machine and leave it in the clamps until you are finished.
So, once secured to the table, the top right side would have been higher than the left front corner where the Z measurement was taken. By cutting deeper, the VBit wouldhave cut the lines thicker than intended and the black lines would have overlapped making one solid black area.
I'm going to chaulk this one up to a rookie mistake and give it another go. (I am going to try a 30 degree engraving bit though
Thanks to you all for your input!!!
What's the issue with "clamps that apply force to the edge of the board"? How do you clamp it down if you do not clamp the edges?
When I wrote about edges I was referring to the thickness of the board. Some folks use wedges on their sides to push the board against fixed stop rails. Those work to a degree if one is doing light cuts. Like anything, a person can do that all the time and then one day. . . .
Once hot glued down, I flattened the top and then did the engraving.
You are probably correct that some of the hot glue let go. It is handy stuff. My guess would be that after you hot glued it and then surfaced it a bit of stress was relieved in the board and there was enough force to pop a corner up on you.
martin54 wrote:One other thing while I am being blabbly: Have you surfaced the spoil board on your machine?
Have you trammed your machine? One other possibility is that the machine Spindle is not sitting quite true to the spoilboard.
firstshot425 wrote:Ted or anyone else.
Have you tried the +painting tape + super glue" hold down method? Here is the link to YouTube link where Fast Cap 2P10 glue and activator is used.
martin54 wrote:If you look at your final picture there is a very large part of it that looking at the Toolpath preview should not have been cut yet seems to be very black
The area above the bike according to the preview is not cut at all.
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