I am building modular benchwork sections out of hard wood. I want to screw together 1x4’s in a box shape. My question is this- should I predrill holes on the outer boards, or just try to drive screws through both? I am looking at using drywall type screws.
Roger
ROGER,
If you are using hardwood, yes it is a good idea to predrill your holes. I teach my kidos at school the three steps for properly putting screws into wood. Yes we to use drywall screws. The steps are.
Pre drill with a 1/8th inch drill bit.
Use a countersink bit and countersink for the screw head. If you don’t do this screw head won’t sit flat, and sometime will split wood.
Use #2 Phillips head driver to drive srews in.
Also it helps doing this for softwoods to especially near the ends so they won’t split out. It takes a bit longer but the results will be better.
Hope this helps?
laz57
I would not use drywall screws for anything that might be called upon to support a person. They are brittle and have little shear strength:
http://www.ehow.com/how_5482375_dos-dangerous-donts-drywall-screws.html
Deck screws are much more suitable and very similar in shape to drywall screws. They cost more; but they’re worth it.
The building codes do not allow you to count any strength for fasteners driven into end grain. If you’re planning to screw boards together that way, you might be disappointed. Put some blocking inside the corner and screw into that.
Thanks for the help guys. I am building 2x4 foot modular sections that will never have to support any real weight. There will be 2x2 legs in each corner. That is why they must screwed together without extra blocks. This layout must be able to be moved due to the location.
Thanks,
Roger
If you want to make the deck as stiff and light as possible, build a monocoque. Put a face sheet on the bottom of the deck. Make sure that the 1x4s run both directions to provide a shear tie for the face sheets. Screw everything together, and it will be very stiff. The only disadvantage to all this is that you have to drill holes through both face sheets to run wires. The advantage is that you can get by with very few legs.
If I were going to make a layout in my garage, I would make a monocoque (fancy name for a box) and suspend it from the ceiling with a method to raise it above the cars when not in use. I would use 1x4s for the risers and use 3/8 plywood for the top sheet and 1/4 plywood for the bottom sheet.
A few years ago, my son made a large sleeping platform for his dorm room at school. We did the analysis to determine the thickness of the face sheets assuming there were 4 guys on the platform. The risers were 2x4s, and the top sheet was 1/2" plywood and the bottom sheet was 3/8 plywood. The platform was 10’ x 10’. The reason the top sheet was thicker than the bottom sheet has to do with local stiffness in between the risers. We put the risers on 16" centers. If you use 3/8 plywood for the top sheet, it will be quite springy if you walk on it. The stiffness of a sheet of plywood varies as the cube of the thickness, so going from 1/2 plywood to 3/8 plywood reduces the stiffness by 58% or put another way, 1/2 plywood is 2.37 times as stiff as 3/8 plywood.
Bruce Baker
I’d get a tube of hard as nails and glue the joints of the frame also… the type for a caulking gun … [2c] you’d be surprised how much stronger and less wobbly it will be .
ROGER,
My layout is made with 2 x 4s and I have homesote on top for sound deadener. 2x4s are spaced out every16 inches. Each stud has 3, 3inch drywall screws on each end that are 34 inches above floor. I weigh 220 lbs, and never had any problems holding my weight. So what your doing in my professional opinion is fine it will support you and your trains.
Hope this helps,
laz57
American Forest & Paper Association: “…structural loading of wood screws in withdrawal from end grain has been prohibited since the 1944 edition.”
http://www.awc.org/pdf/NDSCommentaryCompressed/Part11WoodScrewspp133to139.pdf
Laz, as a wood shop instructor, I know you know your business. Good job. Maybe Buckeye will jump in with his engineering degree and show his foam construction. I used Laz’s type and used Soundstop instead of Homesote. No difference.
I am not disputing the the shear strength of drywall screws because we are not going to support a bathtub filled with water or any other heavy load bearing items. This is a layout with track and trains on it.
laz57
I use drywall screws usually. It’s easier to snap the zinc wood screws just screwing them in. I don’t snap many drywall screws. I never snap deck screws. I’m more worried about snapping off screw heads than it pulling out of the end grain of wood with train layouts. If you are worried about it, glue them up before you put the screws in. If your type of layout includes a top plywood board, then don’t worry about it.
BTW, if you build a monocoque, you don’t need to fasten the risers together. The riser joints don’t carry any load.
Bruce Baker
Yes, I used drywall screws [black] to screw down Realtrax to Soundstop [which is soft]. Works great.
Laz…Here again you are confusing Live Loads, Dead Loads, and Impact Loads. Are you designing in Working Stress, Ultimate Strength or Load Resistance Factor Design with a homogeneous or non-homogeneous material? Are going with the grain? The empty bath tub is a Dead Load. The water you put into the tub could be considered a Live Load, depending on how big of tub you own, and when you dive in head first, we would call that an Instantaneous Impact Load with a broken neck.
Before I added on to my layout, the 5x16 section weighed about 100 pounds with the foam. Add some trains and maybe we are now at 115 pounds. (My Williams Locomotives are really heavy.) So that puts us around 1.4 lbs per sq. foot for the layout, but wait a minute it only has four legs beneath the frame. Each leg is transferring to the floor about 29 pounds.
Now if I sat the Chief’s butt into a four legged bar stool in my train room, and we take how much he weighs and divide it by four: 400 lbs / 4 legs = 100 lbs per chair leg. (There is something call punching shear, but we only talk about that when we tell about the time when the high rise condo collapsed in Florida because a couple of aeronautical engineers working outside their professional disciplines thought they could design buildings and did not know about punching or peripheral shear around the columns and they were using pan joists and concrete. Ka-BOOM!!!)
A residential floor, depending on the state, county, township, city or village is to be designed for a Dead Load in the neighborhood of 12 lbs per sq. foot and a Live Load of around 40 lbs per sq. foot. I beli
BUCKEYE,
ROTFLMAO!!!. OH I DO love that IMPACT LOAD, but my aching neck. Gonna have to try that sometime?
LOL, totally AWESOME!
laz57
I just love to read how you guys get a “load on” talk about benchwork loads. Am always learning something. [:)]