I finally built a prototype of a marking gauge with a cutter wheel out of some scraps.

https://lyse.isobeef.org/tmp/streichmassprototyp-mit-messerrad/

It had been a long time in coming, I bought some replacement cutting wheels three years ago for exactly that purpose. I also found out that I need more M3 countersink bolts for future marking gauges that I want to make (maybe two or three more). Luckily, I had exactly one. I thought I got way more than that, but M3 is very, very scarce in my collection. My M3 bolt was barely long enough to attach the cutting wheel to the bar. But it’s okay for the prototype.

I was pleasantly surprised that I managed to drill the 2.5mm diameter hole almost perfectly in center in the 8mm diameter aluminium round bar. Center finder, drill press and vise with a vertical prism for the win!

I knew upfront that the M5 steel bolt to lock the bar in place definitely needs to be replaced with a brass or aluminium one (maybe with a knurled head). Otherwise, it cuts into the aluminium bar and leaves ugly marks. These burrs might even scratch the workpiece. But, of course, I don’t have any brass on hand either. Alternatively, I swap out the aluminium bar for a steel or even stainless steel one. Stainless might be tricky to precisely drill and tap, though.

I already learned a few things by making this prototype. The final wooden fence can be even a bit bigger. This round thing behind is also too short, I’d like it to be a tad longer and thicker. The final one will be made from hardwood, not spruce. Other than that, it’s great and already more practical than my store-bought marking gauge with its round fence. This only causes the tool to roll around on the workbench. Or even roll off. Stupid design.

Of course, the tiny M3 bolts are in a completely different section a few aisles further down than the rest of the bolts and screws. Took me a while to find them. And I didn’t pay close enough attention, I got 19 stainless hex key but one galvanized phillips head bolt, somebody threw it back in the wrong bin. Oh well, at least they’re both seven cents the piece. I only really need two or three.

@david@daiwei.me Thanks, mate! I just finished my two full version marking gauges. And I’m rather pleased with them, I think they turned out great if I say so myself.

https://lyse.isobeef.org/tmp/streichmass-mit-messerrad/

The beech fences (80 and 100mm long) were part of a former table frame that I cut down. I plugged the dowel holes with, well, dowels. The horrific looking one was the stuck original one, though. Luckily, it’s a hell lot worse on camera than in person. If you take a close look, you’ll also be able to see the large but slight chamfers one one side each that I just left alone.

I really like beech wood. It looks beautiful, is rather heavy (at least in comparison to spruce which I typically use) and thus rock solid, is also a blast to plane and the list goes on. I sanded it with 180 grit and it’s smooth as a baby’s bottom.

The 25mm beech round stocks that house the brass knurled nuts are now roughly 4cm long. That’s one thing I wanted to change right after my first experience. If they were rounded or chamfered more, it would probably be even nicer for the fingers when using the marking gauge. They’re sunken in roughly 3mm in the fences. A forstner bit made quick work. This simplified alignment during glue-up a lot. Will definitely do that again if I happen to build more. I could fully concentrate on the grain orientation and it didn’t shift around.

Just like in the prototype, I used 8mm aluminium solid round bar again for one of the marking gauges. It’s also about 15cm in length. I figure that’s enough. The bought marking gauge has a twenty-something and some change steel rod. So far, all my markings didn’t even exceed probably 50mm.

I found the 8mm brass pipe laying around on the workshop. Didn’t know anymore I had it for ages. Unfortunately, the wall thickness is below a millimeter, so my 6mm wooden dowels are sliding in there. Thus, I put 8mm dowels in my drill chuck and reduced the diameter with a rasp. I went a tiny bit too far, the press fit is on the loose side. When drilling with a 2mm drill (I did that on purpose to hopefully cause the dowel to expand a bit more in the pipe, typically the tap hole for M3 is 2.5mm) and tapping M3, the downsized and glued in dowel slipped down the pipe. Should have used construction adhesive or something along those lines. Anyway, I might replace it with a solid one. I consider this a half-successful experiment. I fear that an unfavorable grain direction might pull out the cutting wheel during use. Let’s see.

The finish of all three is boiled linseed oil. It looks nice, but oh by, this smell. I really dislike it. My hands stink even after washing them several times. I still got several liters left, so I have the dubious joy to use it on many, many other projects to come.

Oh, one last thing. Didn’t manage to drill the tiny holes for my M3x16 bolts perfectly in center like for the prototype. They’re a tiny bit off. Also, on the longer fenced marking gauge, the hole for the knurled nut is a little to the side and at an angle. No idea how I messed this up. Luckily, it’s just a look thing but doesn’t impair use.