The VWC website now has a capability to have members post new discussions (called Threads) or comments/additions to exisitng threads. This capability can be used to post projects, including "crv" files and photographs of projects.
Comments/suggestions for new Discussion Topics and other comments should be directed to woodshop@thevwc.org.
Since we started doing projects and testing, some of the users have been using a side pressure technique for holding their materials will machining. Typically, cams and wedges are being used.
Cams and wedges
Why use cams and edges? Because they are quick to set up. Acceptible for engraving but seldom seen in use.
Why not use cam and wedges? Because they are dangerous. I have videos of the cams degrading during a production run. They push to the side, seemingly doing a great job, then start to loosen up especially when milling deep slots real close to the cam. The cam crushes the wood after the slots are milled, destroying the firm grip. In one case the cams moved the wood far enough to damage the tabs and allow a piece to come off the table. Some would argue that we just add more waste material so the cams won't crush it. That seems to solve one problem but doesn't solve the most dangerous problem.
Cams aren't holding the materials DOWN. As the router bit moves up and down physics dictates that the spiral edges of the bit are trying to lift up (for an upcut) and push down (for a downcut) trying to drag with wood with it. This is getting risky and needs to be modified. A mechanical down clamp (not dowels) needs to be holding down the material from two or more places. We are using 1/4" diameter tools that are somewhat forgiving. On a different router that will accept 1/2" or larger tools, this will be out right daangerous and can not be allowed.
Splines pins and dowels
This technique probably came from the you-tube videos showing CNC routing buy someone who doesn't think things through.
Why use pins and dowels? They seem to do the job of holding two pieces together. Another benefit given is that if the tool hits them, the tool will not be damaged.
Why not use Pins and Dowels? For shallow engraving and routing they don't seem to present a problem other than being extra work. For deeper routing of complex designs, the router bit will be placing many side as well as up/down forces on the splines. Using 1/4" bits may be ok for minimal routing. The situation becomes dangerous when we are using a larger router with more spindle power and faster or aggressive feed rates using 1/2" or larger tools.
Solution for both issues above is to use mechanical hold downs to secure the work to the table and protect the table from damage.