Joinery question...

[Steve Wurster]

I'm going to build a learning / kitchen tower for my 3 year old so he can be at counter height with my wife and not have to worry about falling. A quick and dirty Sketchup of the design is as shown.

220540

The rails and stiles/legs will be 3/4" Maple, most likely 3" wide. My question is, how should I join the rails to the stiles/legs? I was originally thinking pocket screws and glue, but then I would have to plug all or most of the pocket holes, and the thought of having to do that isn't too appealing. So then I began leaning toward either loose tenons or dowels. I'm worried that because the material is only 3/4", there won't be enough tenon or dowel in those pieces to avoid racking problems. That brings me back to using pocket screws. Either that or screwing together from the outside and covering the screws with plugs from that side. What are everyone's thoughts on this?

The panels will be 3/4" Baltic Birch plywood, so I'm guessing the best way to attach them would be tongue and groove.

Thanks,
Steve

[Jamie Buxton]

You're right, there isn't a lot of rack-resistance in a bunch of pocket-screw joints. However, there is a great deal of rack-resistance in a panel of plywood. If the panel with the knobs in it is glued to the surrounding rails and styles, it has lots and lots of rack resistance. In the other direction, I'm guessing the three rails are forming a ladder for the little guy. How 'bout making that area a panel too, with two holes in it to leave a ladder-like functionality? The plywood (if the holes don't eat the entire panel) will give lots of rack resistance.

[David Thompson 27577]

I built something similar when my grandbabies were approaching the potty-training stage.

I used bridle joints within each of the side frames, and mortise and tennons for the rails between the sides.

You could, as an effective alternative, use loose tennons or dowels. Unless of course you really want to show off, in which case you'd use dovetails.

[Steve Wurster]

Some of the commercial versions of this use plywood panels on all sides, but I was hoping to get away with a minimum amount of plywood. Especially since the two sheets of 3/4" BB ply I just bought are earmarked for a flip-top stand for my sander and planer... and are already cut to rough size for that. The biggest left overs from that are those side panels shown in the drawing. The plan was to have holes in them for placing 1" dowels that will hold up the adjustable platform.

I could of course get another sheet of BB, but I already have the maple stacked and ready to go.

[Steve Wurster]

David,

For the bridle joints, did you glue and screw or just screw? And did you put the "tenon" part of the joint on the rails or the stiles?

I think dovetails are a bit of a stretch for me on this one. Have almost no experience with them, and would like to crank out this build fairly quickly, especially since I don't get much shop time these days. Do you think loose tenons or dowels would work well even with the mortise in the 3/4" material?

Thanks.

[Myk Rian]

Mortise and Tenon.
Pocket screws are ugly.

[Jamie Buxton]

If you're looking for really simple joinery, you could join all the solid-lumber pieces together with lap joints. Each lap joint gets glue plus two screws. With that much glue face, this joint has plenty of anti-wrack strength. Plug the screw holes with buttons like these. http://www.woodcraft.com/Product/2001121/10465/Buttons-Maple-38-Diameter-Tenon-12-Diameter-Head.aspx

[Steve Wurster]

Perhaps I could use lap or bridle joints and reinforce with dowel pins instead of screws?

[Steve Wurster]

Yeah, I'm not thrilled with the look of pocket screws either. But I'm still worried that creating a mortise in the stock that is only 3/4" thick won't hold up.

[paul cottingham]

I have made several tables with 3/4" stock using pegged mortise and tennons. My daughter climbs on it, no prob. She is the size of an 8 year old if that helps.

[Steve Wurster]

So your pegs went into the 3/4" stock along the 3/4" edge and not the face?

[Myk Rian]

Yeah, I'm not thrilled with the look of pocket screws either. But I'm still worried that creating a mortise in the stock that is only 3/4" thick won't hold up.
A 1/4" M&T will do just fine.
I made a folding step ladder for my Wife using 1/4" M&T.

[Steve Wurster]

By 1/4" M&T, do you mean the tenon was 1/4" thick and also 1/4" long (stub tenon), since the mortise is on the face of a 3/4" board?

[paul cottingham]

hmmm I am not sure I understand the question. I mortised the legs, inserted the tennon for the apron, and pegged it in place using a drawbore pin. Nice and tight, and very strong.

[Sam Murdoch]

You are right to be concerned about racking with a little kid climbing it and out of this structure. Fun idea! I agree that pocket screws are not optimal. They are tricky to get truly tight and flush joints and not very rugged for this application. The frames with the 3 rails and the ply panel can be built conventionally with tenons, or loose tenons, or biscuits, or dominos, or dowels. The 4 rail sides where the rails terminate into the face of the verticals could add a great deal of stability with the following 2 joint options: 1) through tenon the 3/4" rails. Make a 1/2" shoulder at the top and bottom then run the rest of the rail end through a tight mortise. You would need to set your rails in about 1/2" from the edge though for this to work. The end of the rails could be cut flush on the outside or left long with decorative chamfers. 2) Run the rails full width of the unit and do a full 3/4" mortise of the rails into the verticals. Both of these options optimize the glue surface. Having said all that - I don't think that using decorative washer head screws to reinforce any of these joints would compromise the look while adding a great deal of structural integrity. These screws come in all colors and drive options and often can be quite pretty. Just one man's opinion :D.

[Steve Wurster]

In this case the legs are just 3/4" thick by 3" wide. They aren't true legs like you would have for a table. So I didn't know if you were using 'normal' thickness legs or something closer to what I have in my design.

[Steve Wurster]

Your options 1 and 2 seem the same. Does your second one not have any shoulders on the top and bottom?

I'm confused about the 1/2" set back you said I would need in option 1. Is that so I don't have the mortise too close to the edge of the board? And then would the chamfer make the leg board be flush with the set back rail?

[Sam Murdoch]

Your options 1 and 2 seem the same. Does your second one not have any shoulders on the top and bottom?

I'm confused about the 1/2" set back you said I would need in option 1. Is that so I don't have the mortise too close to the edge of the board? And then would the chamfer make the leg board be flush with the set back rail?


Option 1) The rails go through the inside faces of the verticals. The 1/2" shoulders are essential to resist the racking and they provide more glue surface. Yes, I suggest the 1/2" (or more) set away from the face to keep the mortise away from the face. For ease of construction I am NOT suggesting that you shoulder the sides of your rails. Keep the tenon the full 3/4" thickness - just shoulder the top and bottom. The chamfer would be on the end of your rail tenon if you let it run long through the vertical, or just cut your tenon flush with the face of the vertical.

Option 2) is different in that the thickness and width of the rail is set into the edge of the vertical. No shoulder. If the rail is 3" x 3/4" the mortise into the vertical edge will be 3" tall x 3/4" deep. When that joint is complete the rail face will be in the same plane as the outside edge of the vertical. This option will not be as rugged or resistant to racking as option 1, but still quite solid and far better than pocket screws. This is why I encourage you to consider using pan head or washer head screws. These through the rail face in option 2 with a glued joint will be substantial.

If this is clear as mud to you and you need more info, I can do a Sketch Up model tomorrow. If you really need the visual and you think that you are inclined to try one of these options let me know and I'll do this Sunday afternoon.

Sam

[Sam Murdoch]

Then to add to the confusion :D. Both of these options lend themselves to pegged joints. In fact I would encourage that, especially as you have suggested that you don't want to use screws. You could also incorporate corner glue blocks, but I am trying to make suggestions which are in keeping with your plan and description. All this would be easier if you were working with thicker stock. It is a lot easier to build rugged joints with 5/4 stock than with 3/4 stock.

Anyway, back to the pegs. I like square pegs in round holes. Make up some 1/4" +/- square x 2" or so length pegs (more than you need). ALWAYS good to try a few sample is the same stock as your finished joint to see what combo of round hole will work best with the size of the peg that you produce. You don't want to split your face wood nor do you want to have obvious round segments of hole around your seated peg. (Yes you can use dowels with glue but what's the fun in that? ;) ) Once you come up with 2 or 3 good sample results, add a bit of glue and drive your pegs in. That joint ain't ever opening up (kind'a). In option 1 drive your peg all the way through from the vertical face - through the tenon - into the vertical back edge. Option 2 the pegs are your screw substitutes. Will make for a better structure.

[Steve Wurster]

Ah, I understand your part about the chamfer on the end of the rail tenon. And yes, I would like to see a Sketchup of your options if that's not too much trouble. Thanks!

[David Thompson 27577]

David,

For the bridle joints, did you glue and screw or just screw? And did you put the "tenon" part of the joint on the rails or the stiles?

I think dovetails are a bit of a stretch for me on this one. Have almost no experience with them, and would like to crank out this build fairly quickly, especially since I don't get much shop time these days. Do you think loose tenons or dowels would work well even with the mortise in the 3/4" material?

Thanks.

The bridle joints were glued only -- no metal fasteners at all.

As for the mortise and tennons...... the tennons were at the ends of each cross-piece, and the mortises were cut into the side frames.

And yes, loose tennons or dowels could also work very well. But a point should be made here...... the effectiveness of dowel joints can be greatly affected by the quality of your dowelling jig. If yo spend $14 on the jig, you're likely to get commensurate results. But if you spend hundreds on the Dowel Maxx, you'll be amazed. (The strength of the joints is roughly equal, but the placement/

alignment differences are AMAZING.)

[Steve Wurster]

I have the JessEm doweling jig. Bought it last summer based on the review that Bill Huber had done on it previously. Used it for making what is basically a cell phone charging station with some side drawers and vertical storage for mail / iPad. The accuracy of the joints is as you stated: amazing.

[Myk Rian]

By 1/4" M&T, do you mean the tenon was 1/4" thick and also 1/4" long (stub tenon), since the mortise is on the face of a 3/4" board?
No. The mortise is 1/4" wide, and as deep as is practical.
You may need to use thicker than 3/4" stock, especially if it's a corner piece. 2x2 perhaps.
From your drawing, screws through the rails into the cross pieces seems to be your best option.

[Bill ThompsonNM]

Another good choice would be a dowel and a bolt into the crosspiece. Use one of the "knockdown" fittings with the cylindrical nut like commercial furniture you have to assemble. With the dowel it makes a joint very resistant to racking.

[scott vroom]

The answer depends on what you're trying to accomplish with this project. If your goal is to build an heirloom quality stand to be handed down, or if you you view this as an opportunity to practice more complicated joinery, then go with one of the furniture-quality methods described above. On the other hand, if this is basically a throw away piece after a year or two, then use pocket screws and plugs.

[J.R. Rutter]

If I were doing this with minimal tools, I would also choose bridle joints for the sides. Then I would notch for the front and back rails/rungs, and drill through the faces and use flush dowels to hold them in place. Personally, I don't mind round dowel pegs. For a piece like this, you will probably use a bunch of roundovers for edges anyway. Fast, strong, easy.

[Steve Wurster]

JR, what do you mean by using flush dowels to hold the rungs in place? If I'm notching the side of the legs and then drilling through the face of the rung into the side of the legs, are you saying I would use knockdown style cross dowels, or am I reading that wrong?

[J.R. Rutter]

I mean get some long dowel rod (I cut it into pieces about 1 foot long). Glue and clamp until dry or just glue and hold the parts in place and drill matching hole. Glue in the hole (coat the walls) and tap the dowels in. Then flush cut them. You will see the end grain of the dowel on the face of the joint. Then brag about how you didn't use any screws or nails...

[Sam Murdoch]

Sketches as requested: Option 1 assembled, Option 1 exploded, Option 2 exploded, Option 2 assembled. Dimensions - change to suit your needs.

220776 220775 220777 220778

Just a few ideas. Lots of other good options suggested by other posters. Glue all joints of course. Dowels or wood pegs or screws are all good ways to strengthen the joints.

These are suggested ONLY for the 4 individual rails to verticals as seen on the front and back of your sketch. Read my first post for the construction of the rail and panel frames of what I am calling the sides, as seen in your drawing.

[J.R. Rutter]

Great sketches.

Option #2 using round dowels is what I was thinking, assuming you don't want to cut more advanced joinery.

[Steve Wurster]

I see. Sounds good. Thanks everyone.

[Sam Murdoch]

Don't forget to post photos of your finished project! :D

[Brian Weick]

I have used this tool and IMO - it is absolutely amazing,very simple to use and change setups on the fly,incredibly accurate and precise.....just an incredible machine.....

http://fototime.com/99CB340AC2B6105/orig.gif....http://www.youtube.com/watch?v=pzPLUDPolWc&feature=endscreen&NR=1


B,.

[Sam Murdoch]

Yes the Festool Domino. This is my favorite tool, and would have been my go to tool for this application, but I didn't think that OP Steve would have such a tool or consider investing in one for this project. But, Steve - if you have one, please disregard all the above :D.
(Biscuits are another joint option, but not so rugged for this app. so I did not suggest that.)

[Steve Wurster]

No Domino here, and I don't foresee one in my future any time soon. But I do have a JessEm doweling jig and I can also do loose tenons with my plunge router and a template.

[Steve Wurster]

These are great sketches, and they definitely help me understand your ideas. Thanks again.

[James White]

I would opt for option one. Only the tenon cut flush and wedged. Just one more way to do it.

James