tenon length

not too short

bill tindall

>I made some too short many years ago and one broke out. I am near needing the same decision so I am anxious to hear the collective wisdom. I was thinking about 1/2", but that was a guess.

terminology

Adam Cherubini

>The piece in front is a drawer divider. The pieces on the sides are called drawer runners. They usually run in shallow dadoes, but sometimes they are just nailed in. Sometimes they glued little pieces under the runners to stop the drawer from tilting when open. They are called kickers. Sometimes there is a panel inside the frame you made. That's called a dust panel. Full dust panels are when there are no runners and the dust panel takes its place (this is nice albeit early construction, IMHO.

Your runners should be soft secondary wood. The depth of mortise can then be predicated on its length as it's easier to make deep mortises when the mortise is long. IIf I recall in similar circumstances, I make the tenon 7/8"

Adam

Re: not too short

RichardR

>Jack,

You can glue the front mortise in place and just let the runners rest in their dados if you want. Then let the rear mortise float...I would think, depending upon the width of the rear divider, that somewhere around 1" for the tenon length will be fine.

Re: not too short

Jack Guzman from Maine

>Thanks Richard,

I'm going to use 1" for the tenon length.The reason I'm screwing the runners to the sides of the case is to help keep the side from bowing.---Jack

Re: terminology

Jack Guzman from Maine

>Adam,

Thanks for the info on terminology.The whole piece is being made with poplar.Why softer for the runners?Isn't it easier to replace/repair a worn drawer side(or whole drawer)than a built-in component?I'm not disagreeing I just don't understand. If not would making the drawer sides of a harder wood(birch is available)be a good idea?The runners are already built.I'm in the process of chopping the mortises.No drawers have been built yet.--Jack

Re: not too short

Jack Guzman from Maine

>What are you building?---Jack

Sorry

Adam Cherubini

>Sorry Jack, I screwed up. The drawer runners are almost always secondary wood. Usually that means a softer wood than the carcass. But this is irrelevant to the mortises. I was thinking that the mortises would be easy to cut in the soft secondary wood. But the mortises are cut in the primary wood of the drawer divider.

Wear isn't really as big a problem as you might think. Where you get wear is on the kickers. As they wear, the drawer can tilt more during opening and it ends up wearing a groove (well, I guess a dado!) in the drawer divider. The way to prevent this is by using really good (I like QS) stock for the drawer sides That enables you to make fairly tight kickers,and thus elimimate the drooping drawers (I hate it when that happens).

Anyway, sorry for the mistake.

Adam

The rule of thirds & drawer runner material

Andrew F in Australia

>Hi Jack,

We were trained to cut things either 1/3 or 2/3 thick, depending on the application, with the exception that if the joint has the name 'half' in it, we cut it at half thickness (eg: cross halving joint)

I cut mortices to be 2/3 of the depth of the member that I'm mortising into, which is an answer to the 'tenon length' question.

As well, we were trained that drawer runners and sides/slips should be the same material - if the drawer runner is a softer wood, then it wears out quicker (we're talking over 50 years) and necessitates a fairly major rebuild. Similarly, if the drawer sides and/or drawer slip are the softer wood, then you'll be repairing the drawer sooner rather than later. Our training was to make them out of similar hardness wood (but, a light wood is required for drawer sides) to minimise preferential wear.

Re: The rule of thirds & drawer runner material

Jack Guzman from Maine

>Sounds like I'm in good shape woodwise.

I usually make my mortises 2/3 also.These mortises are different though.They're not needed to resist any racking or other stresses.They're not even glued.They just hold the runners in place.So I figured such deep mortises are unneccesary.

thanks for the response.---Jack

Tongue and groove

Andrew F in Australia

>Hi Jack,

Yes, you don't need a mortice for this application.

Drawer runners are usually held in place with a tongue and groove - it was early when I answered your last question and I was answering the specific mortice question.

Just run a groove on the inside edge of the drawer blade and a tongue on the leading end of the drawer runner and it should be enough. For the joint between the back rail and the drawer runner, a shallow trench/mortice mated to a machined tongue in the end grain of the runner; or a single lap dovetail (the 'pin' is full width of the rail) should be more than sufficient.

Cheers,

Andrew