Sunday 9 June 2013

Marking Gauges

I'm making a batch of 48 marking gauges, these have been selling very well recently.
I've always made them of Macassar Ebony which I buy from Bob at Timberline. This is just about the most expensive timber he sells and the wood for each guide costs £5, which is a lot when you consider how small they are. I try to choose quarter sawn stock for stability as well as a fine stripe to the grain.
Macassar Ebony is very dense (it won't float) which gives it a nice weight in the hand. It is also very pretty as you can see from these resawn boards.

The first job is to cut the slot for the sliding bar, I use a piece of wood to set the stops equi distance from the router cutter so that I can flip the bars and rout from both sides to avoid tearout. It takes 6 passes, three from each side, to complete the cut in the 18mm thick stock. This wood is very brittle as well as hard and Bob laughed when I told him what I was using it for.

Anyway all went well and the bars emerged nice and clean with no break out.

The heads were next and these were cut so the the grain is in the same direction as the bar, preventing the fit becoming loose over time. The 2mm groove was cut on the router table, coming from both sides so it was exactly central. These were then cut to size on the table saw.

Next was drilling the hole for the threaded insert which needed to be perfectly central and in the right position for the bar to slide all the way down to the face. By making all the heads identical I could set the drill press up to make quick work of the batch. The excellent Flip Stop system earned it's keep yet again.
The head in the foreground is shown with the inset glued in with epoxy resin.

Time to round the back of the heads. I used a perspex template to mark out the shape of the head and then cut very close to the mark on my smaller Mini Max band saw.  Even with my extractor hooked up I still needed to wear a dust mask as this stuff really makes my nose run.

Here's all the parts waiting for the knurled screws and the blades, I'll put them to one side to settle before final finishing.
In the mean time I'll get another batch of dovetail guides done, it doesn't take long to run short of these.
Notice the spacing between them, you need to treat these strong magnets with respect!

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