Please help me understand the basics of finer project dimensions

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Forum topic by OldBull posted 07-05-2020 06:48 PM 182 views 0 times favorited 1 reply Add to Favorites Watch
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146 posts in 105 days

07-05-2020 06:48 PM

I am still building (arthritis takes forever) the stuff I need so I can build the stuff I want to build. I visited the local “get your wallet out” woodworking store today and saw the next size up of simple dowel jig I need, or so I thought. I have a 3/8” (yes I know that is the dowel size) jig for .75” (actual) lumber and wanted the 1/2” for larger lumber thinking it would be for dimensional lumber. Well I was wrong of course and it made me take a step back and try to figure it out.

The 1/2 in jig (for 1/2” dowels) is for 1” lumber (says so on the box I did not read), of which I haven’t seen any actual 1” lumber. I have used and learned about the 1/4”, 1/2” and 3/4” size loss of dimensional lumber both hardwood and softwood. So where does the 1” lumber come from, and this is the question that made me realize, or think I do, that planers and jointers are for just this purpose, that is why people have them. They would have to come from rough lumber.

So in the end the big question is if you folks are building “nice” stuff that you put money and time into, are the dimensions whole 1”, 2” etc… is there no set anything for building finer projects, decide what size you have and what size it will be after planing and adjust the project numbers? Why a dowel jig that fits 1” lumber?

I am thinking of adding 1/4” to my new 1/2” dowel jig so that it will center on 2×4’s and I can remove it for 1” stuff. I know I can build one but the steel will last a long time.

P.S. After all this, the 1” dowel jig out to actually be .96”, just thought I would throw that in there.

-- My favorite square is 40 grit sandpaper

1 reply so far

View Axis39's profile


277 posts in 407 days

#1 posted 07-05-2020 07:18 PM

If I wanted a 1” final dimension, I would look for a minimum 5/4, but probably 6/4 lumber.

Doubt you’ll find any at the big box stores, but good lumber suppliers will normally have it.

One of my main sources sells mostly 25/32 (which I’d never seen before coming to California). One of the other places I go to regularly sells stuff by the quarts (5/4, 6/4, 8/4, etc.).

And, yes, a jointer and planer are for bringing lumber down to final dimensions – flat, square, parallel, etc.

I have a dowelling jig (General brand, I think?). It does multiple thicknesses and different size dowels…. I don’t think I’ve used it in ten years. I like dowel centers better, but, admittedly, they don’t verify, or assist in drilling perpendicular to the edge of a board. In all honesty, though I don’t use dowels for joints very often. So, I may nto be the most reliable responder.

-- John F. SoCal transplant, chewer uppper of good wood

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