sketching a simple woodworking bench

[walidantar]

it's mostly based on 2" x 4" lumbers .. 30" by 72" by 35.5" or 2 1/2 foot depth by 6 foot width by ~3 foot height

joinery in tenon and mortise but i made that is the mortise is 2" x 4" by 1" or 2" deep so i don't saw for the tenon to reduce work if practically applied and to make it more easy to make

 

 

[curlyoak]

I like and use 1 5/8" MDF. Very flat. Protect it from moisture and water. Varnish it. 2 x 4 garden variety big box lumber is not reliable to flatness.

[walidantar]

mdf for the top only? what should be used for the legs/frame .. i'm was thinking of beech for all the table or pine if couldn't afford beech

[curlyoak]

This is an outdoor table made out of western red cedar. I use the same with spruce for benches.

 

It depends. A lot of people like their shop to look like furniture. I admire that but I don't do that. I get wide 2x lumber. I waste the center. I use 2 x 6 for legs and 2 x4 for horizontal. The 2 x 6's are notched out to receive the 2 x 4's on edge. A bigger notch on the bottom to get the wood off the floor. Glued and face screwed. Long lasting utility. Very adequate for demanding flatness. 

The top floats. Small shop syndrome. It moves for various purposes. I like a 30" H for me and bench work. The bench receives for my TS. If I have several long rips I slide the top and raise a trestle attached to the bench. Set up to do quick. Then make the rips. I would rather have single purpose benches. 

More space is under consideration...

 

[Ronn W]

I like the fact the top is removeable but be carefull how you attache the restraining pieces on the underside of the top.  The top will try expand and contract./

Also, I would cut a recess in the bottom of the members on the floor so that only the ends of the members touch the floor.  Easier to shim if floor is uneven.

Looking good.

[walidantar]

thanks curlyoak & Ronn W 

[PPBart]

Top thickness of only 1.5" may not be sufficiently strong if you do any heavy work -- it will flex and bounce.

 

 

[walidantar]

in this drawing it's 2", i'll try my best to complete the drawing by details, if someday i can i'll apply it .. i'll not glue it evven the frame - i'll bolt it uning bolts

[Coop]

I’m impressed with the drawing itself. Wish I could do that! 

[walidantar]

@K Cooper .. it's really very easy and simple, break it down into sections and parts

the shapes i used is lines and rectangles and often i draw the rectangle with line tool .. the sometimes i make like extrusion with the 'push/pull' button and the same for the mortises .. then link points together .. using sketchup or cad programs helps determine what sizes of wood do i need and how many pieces and take decisions of the design .. it doesn't really need very detailed and specific

for example, i decided the overall length, width and height of the bench based of some commercial models found on the net or market, such as Sjobergs bench height is around 35.5" so i based the design on that measurement .. bt for personal preference i used different measurements  for width and depth

i want to make the frame consists of mainly two sections that are linked/connected by lumbers, each section which is a leg is a shape of roman number 2 [ II ] .. and decided the length of the lumber basicly 28"x4"x4" .. at the end you can add and chamfers or cuts .. simply start by drawing a rectangle 28"x4" then use the push/pull tool and give it the value 4" to make it 28"x4"x4"

then draw the mortises/cavities by locating the center point of each mortise, 6" from the front edge and 2" from the side edge so the you draw a rectangle 2"x4" then use the push/pull tool and give it the value 2" to make it 2"x4"x2"

from inside the mortise, from each corner draw a vertical line 29.5" , and so on, piece by piece .. i drawn steps like an illustration to give the idea and try make it more clear

[walidantar]

i want to learn about the tenon-mortise joint that the mortise is the same length & width as the lumber and so i don't cut a tenon for the mortise however i fit the lumber in the mortise .. is it a weak joint? and if it's ok how much deep should be the mortise - full/  to the other side of the timber or just one ore to inches is ok?

i searched about this but couldn't find any results

[Tpt life]

You just lose the shoulder that can cover any irregularity in the rim of your mortise. Gluing things squarely can also be a pain. It can lead to a slightly slower process, but does not necessarily become a bad thing unless the size of material cannot support the design. 

[gee-dub]

The shoulder is a structural part of the M&T's mechanical strength.  It is also your main supporter (of the tenon) when resisting racking.  I would recommend you go with shoulders.  If you really don't want M&T I would half-lap the joint before I would just "cork" it.

Although this is not the purpose of this picture, you can see how the shoulder engages when a racking motion is applied (to the failure point in these pics but, I think you get the idea):

[Chip Sawdust]

Good stuff there gee-dub thumbs up

[Isaac]

4 hours ago, gee-dub said:

The shoulder is a structural part of the M&T's mechanical strength.  It is also your main supporter (of the tenon) when resisting racking.  I would recommend you go with shoulders.  If you really don't want M&T I would half-lap the joint before I would just "cork" it.

Although this is not the purpose of this picture, you can see how the shoulder engages when a racking motion is applied (to the failure point in these pics but, I think you get the idea):

As a structural engineer, I'm not 100% sold on this. Wood doesn't have a whole lot of crushing strength across grain to begin with, not sure how much that crushing strength is providing. Using a full width tenon maximizes your distance between the extreme tension and compression faces, which tends to be ideal for bending (the same reasons I-beam shapes are more efficient than rectangles for bending).

Even with a full width tenon, you still have the two side shoulders, right? Unless you are talking above a giant mortise that accepts the entire incoming piece without any shoulders at all.

Not saying you are wrong, but just something I'd love to see some tests on. 

[Chestnut]

1 hour ago, Isaac said:

Even with a full width tenon, you still have the two side shoulders, right? Unless you are talking above a giant mortise that accepts the entire incoming piece without any shoulders at all.

Even if there isn't a shoulder if the mortise is tight fitting to the stock the top and bottom of the mortise act as hinge points just like the shoulder does.

With everything structural the moment of inertia is king. With adhesives surface area is king. As you can see above the tenon with the 2 dowels is weaker proportionally to the amount of glue area removed.

At the end of the day if you look at their numbers for the weakest joint, each leg would be able to withstand 333 lbs of horizontal force before yielding assuming a 36" leg. That's 666 lbs for the 2 leading legs if not connected with a lower rail to the other legs and 1333 lbs if they are connected. I don't know about you but I'm not that strong.

[Isaac]

36 minutes ago, Chestnut said:

Even if there isn't a shoulder if the mortise is tight fitting to the stock the top and bottom of the mortise act as hinge points just like the shoulder does.

With everything structural the moment of inertia is king. With adhesives surface area is king. As you can see above the tenon with the 2 dowels is weaker proportionally to the amount of glue area removed.

At the end of the day if you look at their numbers for the weakest joint, each leg would be able to withstand 333 lbs of horizontal force before yielding assuming a 36" leg. That's 666 lbs for the 2 leading legs if not connected with a lower rail to the other legs and 1333 lbs if they are connected. I don't know about you but I'm not that strong.

I agree, and perhaps I wasn’t clear, or I might have misunderstood Gee dubs point. I believe he was arguing in favor of keeping the little 1/4” or so shoulders on top and bottom. I’m just thinking if the tenon was full width, without those little shoulders, it would have a negligible impact, and might be even stronger. 

If you get rid of all four shoulders, you lose the ability to control the depth of the installation. 

[walidantar]

28 minutes ago, Isaac said:

If you get rid of all four shoulders, you lose the ability to control the depth of the installation. 

if the lumber is for example 3" thick and has a mortise that is 2" deep will it solve this problem?

up-till now i would prefer in my case a tenon with no  shoulders for the ease of making .. and with respect to the mortise i see it's maybe possible to make it by hand saw as a dado for the four legs of the bench then laminate/glue the side so the dado becomes a mortise .. this is for ease and making all the four connections more identical/consistent

 

any agree with me :)?

[Isaac]

5 minutes ago, walidantar said:

if the lumber is for example 3" thick and has a mortise that is 2" deep will it solve this problem?

up-till now i would prefer in my case a tenon with no  shoulders for the ease of making .. and with respect to the mortise i see it's maybe possible to make it by hand saw as a dado for the four legs of the bench then laminate/glue the side so the dado becomes a mortise .. this is for ease and making all the four connections more identical/consistent

 

any agree with me :)?

well, this is a bench, so perhaps the precision isn't quite as critical. I'm just saying the shoulders serve as a stop. Relying on the depth of the mortise is just not as precise, in my opinion. In particular, once you add some glue, it is easy to have the tenon not quite fully inserted.

[walidantar]

how much glue takes from space? i thought it's not to be taken in account

[Brendon_t]

Soo... Why are we trying to reinvent a joint instead of just learning to (assumption) / cutting a time tested mortise and tenon? 

It's a work bench but you keep saying you are making choices on what's Less work..  why build a workbench if you don't want to work?  Buying a pre engineered and assembled bench is way less work. Harbor freight special, no glue, metal hardware like you intend. 

Seriously, with no real joinery and using bolts to assemble . I'd bet many could slap the bench shown together faster than it took to make the SketchUp rendering. 

[walidantar]

totally been misunderstood, working less is not don't want to work, but accomplish a task with less steps

[Brendon_t]

21 minutes ago, walidantar said:

totally been misunderstood, working less is not don't want to work, but accomplish a task with less steps

If you can accomplish the Same task with less steps, more power to you.

Removing the shoulders does weaken the joint. A lot or a little, it isn't the same. Personally, I would rather use a tried and tried and tried and tested method, over saving 2 or 20 minutes. 

[wtnhighlander]

The goal for any wooden construction, using cut joinery, should be to first design and form the joints so that they may be assembled WITHOUT adhesives, and the object will hold its proper size and shape, at least under the force of gravity.

Tenons without shoulders provide no gauge point to register them in the proper position. You may get by with shoulders on just 2, maybe even just 1 side. But if no shoulders are used, there is a huge risk that your parts will not fit together correctly. The rail on one side will not insert to the same depth as the other side, and your bench will become an irregular polygon shape.

As for any (closed) mortice, there must be space for collecting glue that isn't immediately absorbed into the surface of the wood. Otherwise, you will be attempting to compress a liquid, which will not, and the tenon will stop short by some unknown amount.

We must realize that people have been working wood since there were, well, people. Plenty of time has been allowed for the mistakes to be made, and lessons learned. Don't repeat those mistakes - that is the greatest efficiency you are likely to achieve.

[Dmatt]

I am a complete noob  to woodworking,  amsd have found this thread very imformative.  I have only built 1 bench with mortice and tenon joinery.   I cut 5/8"thick 2 1/2" high by 2" long tenon on the ends of 1/2" by 3 1/2" strechers and  4by 5 corner posts.  I read somewhere that a tenon should be 1/3 the thickness of the main beam  and 3 times as long as thick.  Is this normal porportions?