I noticed alot of people on youtube use conduit or pvc for dogs to position their work piece. Just curious is there is a advantage over using wood dowels (which I’ve been using). Are their diameter more consistent? People think wood movement will be an issue?
I was just contemplating an updated spoil board and was thinking about the same thing. I was thinking maybe short lengths of pvc were more likely to be straight whereas dowels would be more likely to hold a bend.
I use blk 20mm plastic electrical conduit.
Light rub with some fine abrasive gets it to be a good fit I also wrap a bit of bright tape around the top to hopefully catch my eye before I press go if they need to be removed.
My thinking with plastic conduit was the thin wall thickness if I did make a set up error or a toolpath error then even a fairly small cutter would cut through it and hopefully not break, up to now my theory has been correct lol
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Hey Espressomatic, hey all,
however alredy these two different dog hole standards (3/4"=19.05 mm, and 20 mm) are headache enough. As an European I tend to use SI units like the rest of the world (which means on planing workbenches we have are 20 mm dog holes, as well as on my beloved Workmates (invented by Ron Hickman OBE) and to ignore the imperial/U.S. customary things, but I am a big fan of Veritas workbench products (and their handplanes!) so I always have the need for the 3/4" holes which are uncommon here (I often use Veritas Worksurface). Unnecessary to say that this 0.95 mm (5/128") difference make them totally uncompatible 
So sad that even if the U.S. were among the first to take part in global metrication and introduction of international units in the 19th century (possibly to show their newly gained independence from the empire), and in science, medecine, military, etc., it was a big success, they still cannot convince construction sector of their population. I heard that it’s also the fault of teachers who say “Okay today we will do metrication and calculating in powers of ten, spend a few hours with conversion, but you will never need it” – don’t know if it’s true).
Hey Espressomatic,
yes, they already had some tools in 20 mm option before, but not all.
Unfortunately that will not help my drawer full of 3/4" bench dog workpiece holding tools But it may influence which holes I will put into a new wasteboard design
I really like using pvc bench dogs. If your bit runs into them it cuts right thru them. Also you can drill a hole thru the center to making twisting in and out easy. Wood might split when you are doing this.
One stick of PVC, will last you a very long time.
If you get the fit right it also create a good level of friciton.
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I my experience, commercial wooden dowels are often slightly elliptical. One dimension changes with the humidity level, so even if they were turned circular, they don’t necessarily stay that way. For PVC pipe, the outer diameter is well-controlled, since it needs to mate well with the inner diameter of PVC pipe fittings.
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