Hi all, Sami here from CNC Router Parts. I'd like to show you one of my favorite
workholding techniques. I'm demonstrating this on a small project but it works
really well for production on large sheet goods especially if you're cutting
out an array or series of pieces that are tightly nested. The most important
thing about using metal fasteners is to be sure that we don't place them in a
location that overlaps with the tool path because CNC Gods forbid you hit a
metal fastener with your router bit. There's also a thorough Vcarve
walkthrough at the end if you like to stick around for that.
After turning on the machine and "Referencing all homes" in Mach to ensure
that the gantries are aligned I like to ensure that my material is also squared
at the gantry. To do this I'll engrave a square pocket with Dogbone Fillets
roughly the size of the material. We can place the material in the pocket
and snug it up to the front left corner knowing that the pocket is square to the
Machine. I'll zero the z-axis with my touch plate and check out the
description below for a video about this tool.
Then I'll drive the spindle over to the corner of the waste board and manually
zero X and Y in Mach.
After this I'll install a few strips of scrap wood to create a pressure fit jig
around the material. In most cases this would be enough to hold the material and
run the program but we'll have it hold the material place while we run our pilot
holes. This works really well because our V-bit puts a light downward pressure and
doesn't pull up on the piece like an up cut or down cut might. As you can see it's
fairly tight. Also, notice that I added dog-bone fillets to the pocket to ensure
that the corner was cleared out for the material to fit not be limited by the
radius of the router bit. Now that our material is temporarily secured we can
run our drilling low-pass with our 90 degree V bit.
Now I can finish drilling these holes by hand and screwing the metal fasteners
knowing that with their precise placement there isn't any risk of our
router bits hitting with fasteners and then we can run the rest of our program.
Thanks everyone for watching this pro tip video. Check out our channel for more
scenes who are cooling solutions tools and accessories such as the Auto Z and
Corner Finding Touch Plate. Keep it up and keep making, I'll see you in the shop!
This is our V curve walkthrough. I'm working on making a clapper board for my
filmmaking setup. Let's go through my hold down technique for the main walnut
board the body of the clapper board is cut from. I want to be sure that the screws
will not be in the way of the exterior profile of the tool path.
We'll create a drilling tool path outside the exterior profile to guide our
placement of the metal fasteners. I'll create a new layer for hold-down pilots
this will make it easier to select them later on. We can draw a few circles
around the border of the drop material. I like to leave my exterior profile
visible with a solid view on for reference. The circles are a bit
oversized but an overestimation of their diameter is better than under. Now we can
go to the layers tab, right click and "select layer vectors." This will select
the circles on that layer. We'll go over to the right side panel and create a
drilling tool path this will drill in the center of each of the vectors that
we have selected. I'll select the 90 degree V bit so that the screw heads
will be countersunk into the material. Go ahead and set the depth, I found that
.02 inches was just right. You can name the tool path something that you'll
remember I'll call mine "hold_down_pilots_90_Degree_Vbit"
Now we can preview our
exterior profile and our pilot holes drilling tool paths.
Looks good to me! As always thanks for watching we look forward to sharing more
tips and processes with you soon.