Z point, proximity to material

[george.ducharme]

Hi,

Working on text (using a v bit) and some of my letters are rounded. Thinking the bit is carving too deep. In order to get a consistent depth of carve each time, what techniques do you use to set a z point? Piece of paper between the bit and material? Thanks for any advice you can offer.

[gkas]

I use either the paper technique or my puck. Another big factor is making sure your spoilboard is flat and perpendicular to the Z-Axis. Your material should also be very flat. The shallower the cut, the more noticeable any error. You can always skim a little from the top of your work piece, then you Vcarve should be perfect. On important cuts, I either skim the work piece or run the piece through the drum sander.

[Xxray]

As gkas implies, your issue is more than likely a leveling issue, especially if only some letters are affected.

Things you can try - Check the level on your spoilboard, ifs its off you can either resurface it to get it level, or use a sub spoilboard on top of it and shim it up until its level [of course, you'll also need to figure a way to secure it to the table].
If it is level, your workpiece may not be consistent thickness. Is possible too that you are losing z steps in your machine and/or the gantry is not square to the table, but save those possibilities for last.

[FixitMike]

This can happen if the tip of the V bit has broken off. Also, in this case, the bottoms of the single pass lines will have a flat.

[TReischl]

That piece of paper trick should be tossed in the circular file labeled "things that sort of work sometimes" or put in the file "when accuracy is really not all that important".

I started out that way. Then I moved on to using a small piece of square aluminum bar stock .5 X .5 X 3 inches long. Used it like a feeler gage. Worked better than the paper. But it is still not as good as using a puck or other piece of flat material wired into the machine. That is what I do these days.

I still use the square aluminum bar to find edges.

You will think that you have died and gone to heaven when you start using a puck to set depth. Things just come out perfect every time depth wise. And none of that "jog a thou, feel, jog, feel, jog, feel, oops, start over stuff"

[armbrusterco]

If your controller is not set up for a wired puck sensor, you might use a Z axis dial setting zero gage. Not as easy, quick or smooth as a wired puck but very accurate and it works with fine tipped V-cutters.