Some bad ideas are based on good ideas, but they just took a bit of a wrong turn that makes them less useful, and in some cases potentially dangerous ... which are the ones we all want to avoid and that's the whole purpose in doing this series, is to help one another spot potentially harmful scenarios. 

Watch it on Youtube:

We all hate accidents in the workshop, even small ones like cuts and bruises. As much as I work to avoid even these, I still end up with the odd one but my awareness is getting keener to things that can go wrong because it's something I have tried to train myself to look for ... I surely don't get all of them, but I still work at trying to recognize problems before they amount to something. 

I do very little electrical work except for some repairs once and a while and when I do, I sure I am way over code for repairs because I want to make them as secure and long-lasting as possible ... but evidently, not everyone does that. Someone sent me a picture of this first bad idea, it took me a few minutes to figure out what the picture was, and it was dark and hard to see, but when I saw what it was I couldn't believe my eyes, someone  was apparently trying to hook up one of the woodworking machines to a wall reciprocal by direct wiring it and using plastic "zip ties" to connect the wires. I had to replicate a mock-up of the picture for the video clip and really, don't know if this was done as a joke, of somebody seriously had tried this but either way, it's a good lesson in using proper electrical connections for anything you do related to electrical power set-ups.

bad electrical wiring

Table Sawing Curved Wood
This is a topic that needs reminding from time to time because it can be so easy to skirt around it, especially when you have just come back from the lumber store and have had handpicked the wood yourself ... and off you go to start trimming it to width. Then find out partway through your first cut that the board is not straight and flat, and now your table saw blade is binding on it and is wanting to fling the board back at you ... also know as "kickback" and the worst kickback you can have is that where you were not expecting it with such force and power.  We all expect some kickback when pushing boards through a table saw, but sometimes when wood jambs into the blade you can end up in serious trouble in the blink of an eye ... not to mention you can't get a decent cut of wood when the wood  that is running against your table saw fence is curved.

Any wood that you are pushing through the table saw needs to be flat against the table saw top, and straight against the table saw fence. If you do not have a jointer, there are other ways, jigs, and techniques of making the wood flat and straight ... and safe to cut. 

Table Sawing Curved Wood

Measuring with Plywood Thickness
This was something learned a long time ago at a course I once took, and somehow I knew that plywood was not always the same thickness but didn't know why.
As I understand it ... all (or nearly all) plywood manufactures belong to an association that sets the standards for plywood. One of the standards is that plywood should be thinner than it's designated size. For example, a sheet of 3/4 inch plywood should never exceed the thickness of 3/4 inch which means most plants will make their plywood somewhat thinner so that when you purchase it, the plywood will be varied by how thick it is, but it will be less than 3/4 when you purchase it. 

What this means for novice woodworkers is that if you are making a bookcase for example and out of 3/4 inch plywood (which is a great choice) if you cut your dados using a 3/4 inch router bit, or set the dado blades in your saw to 3/4 inch, you dados are going to be much too wide to fit the 3/4 inch plywood shelves. 
So what this all tells us, is that using 3/4 inch plywood for anything more than a rough measurement will not give a true or full width, and is also the reason that when cutting dados for plywood shelves, each piece of plywood should be measured to ensure size. 


Bench-top Mounted Sandpaper Cutter
Using hacksaw blades for cutting sandpaper sheets has been around for a long time ... it's where you use the hacksaw blades that is creative and mounting a hacksaw blade to the side of a workbench top, may not be the best idea unless it is in a spot that never gets uses or a part of a bench that is out of the way. A couple of issues crop up when mounting a hacksaw blade to the frequent work location on the bench. First, there is a good chance you will be rubbing, cutting or wearing your clothing ... if not catching it on the blade but he bigger issue could be dragging a workshop cord back and forth over the hacksaw blade which could eventually cut through the power cord.  There is, of course, the option of mounting it with the teeth down, but now you will be struggling every time you want to cut a sheet of sandpaper because there is not a good place to hold it against,
The quick and easy solution is to have a small portable one, close to you your sandpaper supply, that you can then also mark for various sizes you use. I mounted mine using a pop riviter so that the base would be as flat as possible .. it works great and is handy, safe and I can use it where I need it.

 Bench-top Mounted Sandpaper Cutter

Planing Wood on the Router Table (not good)
I have never tried this and at first blush, it might sound like a good idea - but it's NOT, and here's why.  The router bit as it sits in a router table, rotates in counter-clockwise position and we push wood through the router bit running from right to left because the router bit has at least half of its diameter behind the plane of the fence, so the cutters are cutting into the wood as we are pushing it through.

If we move the fence back so the router forward from the fence to allow for the wood to pass between the router bit and the fence, and continue to push the wood through starting on the right and going toward the left ... things are very different. In this case, the router bit is still turning counter-clockwise, but NOW that rotation is ruining WITH the grain of the wood. What will happen here is that in all likelihood, the router bit will grab the wood we had intended to push through the router fence, and will ... in the blink of an eye, wing it out the left side of the router table and fence. This alone is dangerous to anyone downstream of the router table, but maybe even more dangerous to the person holding the wood because there is a chance it could severely cut fingers or hand by instantly pulling the wood and along with it the operators fingers or hand, or ... even a push block, none of which would be expected.

I would still NEVER recommend this technique, but the only way it could work would be to feed the wood from left to right, which would be pushing it into the router bit because the cutters are now behind the main body of the bit. One of the big problems with this all the amount of wood chips and sawdust that would be hurled at the operator ... so all in all, there are other much better and safer ways to thickness trim wood.

 Planing Wood on the Router Table

One of my woodworking instructors, when I was new to woodworking, encouraged me to visualize what happens during the wood forming process. I have been doing this automatically for longer than I care to think, so some ot the things I show are a result of questions from viewers on techniques they are familiar with, and good for them for asking ... that way we can all be alerted to processes that are good, and others to avoid ...

Copyright Colin Knecht 

 Bad Ideas in Woodworking - Episode 4