Screws or Bolts??

[Wade Samuelson]

Greetings,

After conducting an informal poll here, I have decided to build a bench for my miter saw. I modified a very basic design (don't forget I'm brand new to all this) I found on internet, got the lumber, and began cutting. As an aside, I got to use the miter saw for the very first time--it throws a ton of sawdust! Anyway . . . a buddy strongly suggested that instead of using 3" screws, that I use bolts to hold it together. What do you think??? (If it helps, I am using essentially this design: http://www.hammerzone.com/archives/workshop/bench/below20.html and am adding wheels to the bottom. And instead of OSB I am using 3/4" mill cert plywood for the top and shelf).

Thanks again for doing my thinking for me!!

Wade

[Rob Russell]

Wade,

I see a number of potential problems with the design of that workbench for what you want. The basic design is simple enough and would work for a stationary bench, but needs some modifications to suit your purposes. I'll go from easiest to hardest to fix.

There are no supports running under where your SCMS will be. You need additional 2x4's running front to back, otherwise I'd say the top will develop a definite sag over time.
Trying to attach wheels to the bottom of a 2x4 is either going to be a real challenge, or the wheels are really, really weenie. I'd move the bottom shelf support right down to the bottom. That gives you a 3" x 5" place to lag bolt on casters.
You need a design that will prevent racking as you roll the whole unit in and out. That means triangular bracing at the corners. Think about how you want to handle that one.

To answer your original question, I'd screw it together with some glue or construction adhesive. Bolts are best where shear strength (breaking the screw/bolt because of weight hanging on it) is important. That's not the case here. You want a better bite into the wood and the bolt, because it's going though a hole, has to allow for a little play.


Thinking about it, I'd probably put a layer of 1/2" plywood across each end of the unit and across the back. That's the simplest way to stiffen the whole thing up and will keep things from falling out as you roll the unit in and out. I'd also add another horizontal 2x4 in the middle of each end. The 2x4 will give you something to help support whatever you use to hold the wings up.


Rob

[Mike Cutler]

Wade. I don't mean to disagree with your buddy, but if you are executing that design as shown screws are the way I would go. The construction adhesive that Rob suggested is a good tip also. Clamp all your corners together tightly and then screw them together, this way the screw is not pulling the wood into position. The top and the shelf should help with the shear in the horizontal axis, but Rob is correct about corner bracing for vertical shear( racking). Another way to inhibit the racking is to install a 4" wide piece of plywood under the 2x4 cross pieces, top, bottom and sides and screw them into the vertical uprights. If it were me,I'd screw a 3/4" MDF layer on top of the shelf and the top for extra weight, and have a sacrificial surface that can be reapplied, and put in some more horizontal supports under the top and the shelf, like Rob suggested.
It's a good basic design. My main workbench is built along the same simple idea, but is much beefier. It's amazing the amount of stresses a work bench sees in the shop.Mine is 8'x3' and 39" high and weighs close to 300 lbs, and doesn't move one iota.
Build it solid and build it heavy, and it will last for years.

[Bob Smalser]

Sorry, but I don't like the design at all....no accommodation for shear in the structure and too much strain on the fasteners, even with some shear support added. Side to side racking stress...like when you slide a heavy wet 2X12 onto it...will be on the fasteners directly, and that's not a good plan...they'll loosen much faster and the structure will eventually fail.

I'd sure add crossbracing between the back legs and use glue and screws for assembly. Either poly glue or construction adhesive is fine. Bolts don't add anything except the ability to tighten after they work loose...and the glue accommodates that.

I'd also let those rails into shallow rabbets cut in the legs to provide steps that will take strain off of the fasteners, aid the structure on keeping square, and provide a greater gluing surface. For thick rails, I would rabbet the rails, too for the even greater gluing surface and stability of a shiplap joint:

http://www.woodworking.org/Exchange/Forum2/HTML/015066.html

http://pic3.picturetrail.com/VOL12/1104763/4775424/60398418.jpg

[Michael Cody]

I guess I am in just disagreeing mode this week.. The points raised are all valid but I think it's overbuild to worry 'bout a lot of it. I wouldn't worry 'bout racking at all.. the only change I would make in the plan is use adhesive on the joints and put in a couple extra cross pieces in the center to prevent sagging. 3/4 Ply should be fine, me I would use BC personally but better ply would make look nicer .. maybe I am just cheap, but it's just a bench to hold a saw, not fine furniture.

As to racking, remember this is for a mitre saw and it's not going to see much in racking force but the top & shelf all attached to the stretchers will give it all the stability it needs. In particular if you glue the joints. This design probably won't be around 200 years from now like some super duper hi-end bench, but it will last 20 years or more I am sure. That said it's not much more work to put in 2x4 cross braces on the corners... like in the pic ... it would stiffen it up more and only take a few minutes. I would put in 2-3 screws, some shorter ones on each corner and a long one through the center maybe ... glue on the ends too.

Lastly I would lag bolt/glue some 4x4 pieces (either 2x4's glued up or a 4x4) across each end at the base of the legs, to put the casters on...

[Wade Samuelson]

Egads! Rabbet? Shiplap? Seriously, I'm on about day 4 of my woodworking career--I don't even know what those terms mean. But, I do appreciate the advice and will incorporate as much as I am able. I'll switch to 4x4's for the legs, add additional supports for the top, and brace the corners. Plywood backing is also a great idea. I think the rest is a little beyond me at this point. Maybe 5 years from now, I will have a good laugh at this bench, burn it, and build a new one.

Thanks again for the help--you've just saved me from wasting time and money!! I am grateful.

Wade

[Michael Cody]

Wade -- if you are going to use 4x4's for the legs.. just use your handsaw or circular saw to notch the tops and on sides for the shelf like this:

[Rob Russell]

Bob,

I disagree that #8 deck screws don't have enough shear strength for the purposes of this workbench. I used those to anchor an attachment point for a comealong to winch down a 1600 pound machine and the screws held. He won't be putting anywhere near that force on them. Wrapping the 2 ends and back with plywood would provide more than enough racking resistance. That's what holds our houses up.

Still - rabbeting the ends is a great idea from a learning perspective, would be great practice for Wade and a really good addition to his project. Just so "you know that I know", the rabbets will make for a stronger bench than just screws and glue alone.

Mike,

You might want to read This Thread (http://www.sawmillcreek.org/showthread.php?t=12107). It's Wade's earlier thread where he described how he will be using this workbench. Once you read the thread, I think you'll agree that racking is an issue because this is not a stationary bench.

While the bracing you suggest would work, plywood is easier and actually provides significantly more racking resistance.

Wade,

If you're going to go with 4x4's as your legs, it's really easy to "rabbet" the ends as Michael described. On 2 adjoining sides, mark the leg 3 1/2" in from the top and bottom. Make sure you mark the same 2 sides on the top and bottom. I'm sure noone here has ever made THAT mistake before. :rolleyes: Set your saw to a cutting depth of 1/2" and carefully cut on your mark. Now, using the saw, work away at the rest of the rabbet from the cut to the end of the board. Once you get a bunch of cuts, you can use a hammer and chisel to clean out the rabbet. By the way (BTW), when it's on the end of a board like that or runs along one edge, it's called a rabbet. Crosswise, in the middle of a board (like Mike's picture) it's called a dado. A groove is a rabbet that runs down the length of a board, but in the middle not on an edge.

Mike's image shows the top as being rabbetted and would have the the bottom shelf sitting in a dado. I'd still move that bottom shelf all the way down to make mounting the casters easier.

If you put plywood on both ends and the back, you won't need any other bracing at the corners.

If you choose to do the rabbets (and this is a great way to learn on a project), remember to take the depth of the rabbets into consideration when you cutout the notches for your bottom shelf. If this doesn't make sense, wait until you have all the 2x4 and 4x4 stuff cut, dry assemble it and measure for your shelf notches - you'll understand then.

Rob

[JayStPeter]

I agree with the "learn something" idea on this project. But, don't go too crazy. Keep it a simple, cheap, weekend project. It's good to make a bench that will last forever. But, it's also good to just make a bench and get a project done. In a few years you'll look back and say "I can't believe THAT took me an entire weekend".
As for the screws vs. bolts question, I'd use screws. That way, you can eventually disassemble it and reuse the parts. There will always be some shop fixture you can build out of some good dry 2x4s. No sense drilling some big honkin holes in them :D :D

Jay

[Bob Smalser]

Screws and glue alone in the current design will provide enuf shear strength for the piece to last a couple-three years of hard use.

In 10 years or so....when the crossgrain gluejoints fail...there will be no shear strength except as provided by the screws and the piece will begin to fall apart.

The difference between making something that'll hold up for a couple years... and something that will last forever and may live on as a base for something else long after the chop saw burns up...is an extra hour or so of work cutting those rabbets as shown in the drawing above.

You can live without 4X4 posts, and you can live without crossbracing in back....but only if those rails are let into steps.

You can even cut those rabbets on your chop saw....set the saw or workpiece to cut only a quarter inch or so into your 2X stock laid flat and make the rabbets one sawblade-width worth at a time. But quicker ways are the TS with dado blade and miter gage or a simple circular saw to kerf and a chisel to knock out the waste as I show in the pic above. Do the rails that way too and you'll have a half inch of extra gluing surface where you need it....supporting shear.

Or....you can just screw it together as drawn sans glue and dismantle and redo it using proper joinery later after you gain some more experience and confidence.

[Wes Bischel]

Wade,

I built a bench similar to the one shown in your link with the 4x4 legs as shown in Michael's previous post - top size was 48"x60". I used #8 3" screws to fasten the stretchers onto the 4x4s. It saw a lot of use and never moved or became loose. I used it as my main bench for about 10 years - now my father in law is using it as his main bench.

FWIW, Wes

[Christine Tiede]

Hi Wade-

I'm totally new here, so I hope you don't mind me putting in my 2c also, since I finally have something to add!! :o I was watching Norm's New yankee workshop the other day, and he made a Worktable/clamp stand which had *really cool* retractable casters on it. You could have it totally stationary, or you could engage the wheels and move it around. I highly suggest you check it out before beginning your workbench!! (go to his site and search for worktable). It looked pretty straightforward to build, and the idea's great!

Regards,
Christine

[Rob Russell]

Hey Christine - welcome to SMC. Hope you enjoy yourself around here!

[Christine Tiede]

thanks, Rob.... I've been lurking for a while and so far I love it..... even though I'm not yet on the same level as you guys!

[Joseph N. Myers]

Wade,

Your’re head must be swimming by now --- simple question, not so simple answers.

The height of the base of the miter saw is important. You want to have it at the same height of some other piece(s) in your shop (i.e., table saw, work bench) so as to help support your work. Just line your miter saw table up with the other "piece" and start cutting. (If not, you can always use those roller stands).

Wheels are good! I used to use the "good" metal 3" locking wheels but have since converted to plastic locking twin wheel casters, plate stem & brake, 200 pound capacity and really work well. They are around $1.00 from CSH, 800-882-0009, www.cshardware.com. (http://www.cshardware.com./) (You need a minimum order of $50.00 to get the wholesale price but there are so many good things at such good prices, you’ll have no problem getting there).

Big problem with the work bench design (and other miter saw designs) in the lack of storage and too much wasted space. I "helped" this problem by starting off with a chest of draws (trash day pickup), added a top, bottom and 6 wheels giving me a 30" deep x 65" wide x 32" high table. On the top, I added my (1) miter saw with an adjustable stop, (2) desk top drill press and (3) scroll saw. In the back of the table, I added a bunch of storage bins for hardware (see pictures).

By the way, if your not lucky enough to get a free chest of draws, I've seen them at 2nd hand shops for under $50.00. See how you get 6 to 9 draws, that's not too bad.

Regards (and good luck), Joe

[Wade Samuelson]

OK, thanks to Rob's step-by-step instructions, I'll take a whack at rabbets. I have this feeling that I am going to have several useless 4x4's laying around the shop when I'm done! No worries though, I'll use them to test drive my router...

Wade

[Wade Samuelson]

Wade,

Your’re head must be swimming by now
HA! Drowning is a better word!! :rolleyes:

[Tom Sontag]

Rather than chime in on all the tech talk, let me simply state that it is an excellent habit to learn something with each project. And few projects are more forgiving than shop equipment/furniture.

The principle involved here is fundamental too: let the wood surfaces and their contact area provide the strength of a joint and do not simply rely on glue and fasteners.

Explanation using the example of two boards forming an "L": If you simply lay them atop one another and glue and screw, only the glue and screws keep it from pulling apart. You probably could stand on one end and lean against the other with disastrous results. There are several better methods to join the boards that you could use, and one of the easiest and simplest is cutting a rabbet on each end so when you lay them on top of each other, each board also rests on the 'shoulder' of the rabbet, or the ledge as shown earlier. Now if you try to twist the joint apart (still using glue and screws of course), you must also overcome the wood hitting that shoulder. Voila'! Strength!

Practice on the shop stuff and when real projects come up you will have the knowledge and confidence needed, even if the first time did not come out as you'd hoped.

Erenst Joyce's Encyclopedia of Furniture Making was a huge key to learning lots early on for me. Do not hesitate to get it.

[Ellen Benkin]

I hate to put a damper on your building project, but I have discovered the Rockler "system" which includes different length legs and struts (all heavy duty metal) and allows you to build mobile units in a variety of sizes. The wheels that come with it are very good and include brakes. You do have to add a top, and I use 3/4" plywood and bolt my tools to it. You can choose to enclose the unit with plywood and even add a drawer (which you build). I've got a couple of them for things like my drill press and my miter saw and I think they are great. They are very strong, mobile, you can build in storage space, and they wind up being the same height. I hate to spend time building things for tools, and I think this system is a great solution.