# M&T - wedges & pins - Q



## unclearthur (Jul 4, 2013)

I'm building a small workbench with a trestle type base









The joinery is all M&T, with pretty large tenons (stretcher tenons are are 3" long, 3" wide, 1" deep; tenons on the legs are 3" long, 1 1/2" wide & 1 1/2" thick). All are through tenons. Materials are all softwood lumber. Glue is Titebond.

The plan calls for all the tenons to be wedged or pinned.

I've ran across some discussions claiming that with modern glues, wedges and pins don't actually increase the strength of the joint over a regular M&T.

I'd rather skip the hassle (and potential screwups) of the wedges / pins and its just a workbench, I'm not worried about appearances. But obviously I don't want to compromise sturdiness.

2 questions:

i) Need the wedges or pins or not?

ii) If I do wedges, do the mortises need to be tapered?

Thanks for any replies.


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## LittleShaver (Sep 14, 2016)

I like the look of pinned joints. While it may be true that modern glues make them unnecessary, they do provide a bit of insurance. Wedges also look nice. If you use a thin wedge, you shouldn't need to taper the mortises. Your softwood should compress enough to handle a thin wedge. Can't recall where I saw it, but I recently saw a recommendation for setting wedges along the diagonal. Tried it on a stool I made for the wife and it worked well as well as looked good. The stool was in white oak with walnut wedges. Helped hide some of my inaccuracies in chopping the mortises.


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## JBrow (Nov 18, 2015)

unclearthur,

I see no particular benefit to a dowel-pinned, drawbored, or wedged mortise and tenon joint on a workbench unless the fit of the tenon into the mortise is a loose fit. If the mortise and tenon joint has a push-together fit and stay put when handled, glue seems to me to be enough. Since it is a workbench, some screws through the joints could hold things together, but again unnecessary.

One reason to use dowel-pinned, drawbored, or wedge mortise and/or tenon joinery on the workbench is to develop the skill and gain some experience for when it might be a good joinery choice. Also I am not sure how long PVA wood glue maintains a strong bond; I have PVA-glued projects that are holding up after 25 to 30 years. Therefore any project that might be expected to be in use beyond 50 years (just a guess) could conceivably benefit from mechanical reinforcement.

If the mortises are tapered, then it would be best to wedge the tenon; otherwise the gap between the tenon and mortise could be too large to be spanned by wood glue.

I suspect that a waterproof or water resistant glue like Titebond III would be a good choice for a workbench. This glue would be more resistant to long periods of high humidity or more importantly water-based spills than the alternative PVA glues.


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## bondogaposis (Dec 18, 2011)

Draw bored or wedged tenons are not necessary unless you want your work bench to be a heirloom. The life of PVA glue is about 50 years, more or less depending on environmental factors. Draw bored tenons don't even need glue to hold so when the glue fails no one will notice, because the joint will still hold.


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## GregTP (Oct 26, 2015)

I like the design for the bench! I would second the notion that you don't need wedges or pins in addition to glue if the mortise is a perfect fit, however, they rarely are. Especially with through mortises in thick stock, its easy to get off by a little bit here and there. I would draw-bore them. It offers the aesthetic appeal of a pinned joint, which I find pleasing, and will pull your joints tight. Depending on the intended use this will help to keep your base sturdy forever.

That has the looks of a workbench that the grandsons will argue over someday, I would take your time and make it beautiful. One design observation (unsolicited as it may be) that I would offer; it looks like the top and stretchers are the same thickness, I would consider changing one or the other (a thicker top is never bad on a bench) to avoid having stacked elements of the same dimension. If you can find it, George R. Walker had a great article in Popular Woodworking (vol. 184) called "sublime echoes" where he talks about pleasing ratios for echoing design elements


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