Richiep Posted September 14, 2017 Report Share Posted September 14, 2017 Hey All, I just delivered my latest shop cart which came out pretty good for the most part; with one exception, I'll get to that in a minute. The cart will be used in a pole barn on a moderately level concrete floor and spend most of it's time against a wall. It'll be rolled out occasionally and people will work on it from all sides. I started with a simple frame made of 2x3 pine boards, I could have used 2x4s but I wanted that extra inch of vertical space and 2x3's should be plenty strong for this. I don't have a picture but the frame also has 3 more cross braces. 94" X 29" I then sandwiched the frame with 2 sheets of 15/32 plywood, this made a torsion box. I used lots of screws spaced approximately ever 4 inches. This made for strong ridgid base. Next I attached 4 inch locking casters. I've become a bit of caster connisseur as of late and find these from Home Depot to be some of the best on the market. They're economical and high functioning. With a strong foundation I built the carcass from 2x4s using Kreg pocket holes for the joinery. Drawers made of 1/2 A/C plywood and Kreg pocket holes. The cart is 29 inches wide but I only made the drawers 24 inches deep. This made some "dead space" which I later made into cubbies. I attached the top particle board to the carcass using 2x2 pine boards and Kreg holes. The top is edge banded with Red Oak. I'm still learning how to make good clean miter cuts... Luckily most of this was covered with laminate White Oak drawer faces finished with Cherry colored stain and poly finish I finished the ends with pegboard for some additional storage. All and all it came out pretty well and the customer loves it. But one thing is bothering me. At some point late in the build I discovered that the cart has a slight sag in the middle. I put a straight edge on the top and discovered about 3/32 or so of sag in the top and maybe 1/8 inch sag at the torsion box. This really bummed me out, I thought for sure the torsion box was bullet proof. Maybe I should have used six casters instead of four? I could go back and install a couple more casters. Or even easier I could install some shims between the counter top and the carcass, but I don't know... I kinda feel like now that it's all put together that it's not gonna sag much more and I'm obsessing; I've been accused of being a perfectionist in the past.... But I just don't know. What do you guys think? For future builds I'll bite the bullet and use full sized 2x4s instead of the 2x3s. Or maybe I'll use six casters.... Thanks for reading. Rich Quote Link to comment Share on other sites More sharing options...
Llama Posted September 14, 2017 Report Share Posted September 14, 2017 6 minutes ago, Richiep said: At some point late in the build I discovered that the cart has a slight sag in the middle. This is why I'm making mine in two pieces. I need a cart to get lumber into my shop from the semi delivery guy. Then, I can combine them for a larger surface with a built-in gap to jigsaw something, or whatever... Plus, my shop floor is made for draining water out of the shop so it isn't very flat. Anyway, nice table. I'm sure it will serve its purpose for many years Quote Link to comment Share on other sites More sharing options...
drzaius Posted September 14, 2017 Report Share Posted September 14, 2017 6 casters can make for a difficult to drive cart. Go with thicker lumber on the base torsion box, better yet, use LVL lumber for the frame. It's very strong & stays much straighter than regular dimensional lumber. Good job on the table though. 1 Quote Link to comment Share on other sites More sharing options...
mat60 Posted September 14, 2017 Report Share Posted September 14, 2017 Like the shop cart. I just have a small cart for parts myself . Along with the screws did you also glue the plywood on to the base? Quote Link to comment Share on other sites More sharing options...
Richiep Posted September 14, 2017 Author Report Share Posted September 14, 2017 44 minutes ago, mat60 said: Along with the screws did you also glue the plywood on to the base? I considered using glue for the base but decided against it, my thinking at the time was a screw spacing every 4 inches would be enough. Quote Link to comment Share on other sites More sharing options...
Richiep Posted September 14, 2017 Author Report Share Posted September 14, 2017 59 minutes ago, drzaius said: 6 casters can make for a difficult to drive cart. Yeah, I tried six wheels for a minute on one of my previous builds and quickly decided to take them off. Even on a flat shop floor it didn't handle well. I don't remember the specifics but it quickly became apparent that six wheels would be problematic. Quote Link to comment Share on other sites More sharing options...
Woodenskye Posted September 14, 2017 Report Share Posted September 14, 2017 I think part of the issue with the top sagging could be material choice or construction method. If you don't build a torsion box on a flat and level surface any error in the surface will be reflected. The 2x3 if not jointed and planed square could also lead to issues, and the ply used is for sheathing so a better choice may be needed for future builds. I agree that six castors is hard to steer, another option would be to create some sort of leveling feet that could be put in use when parked. Quote Link to comment Share on other sites More sharing options...
Richiep Posted October 28, 2017 Author Report Share Posted October 28, 2017 UPDATE So this has been out in the world for a couple of months now and the sag continues. I've been working on site where this is used and have kept a close eye on it. When I delivered it it was around 1/8th inch of sag now it's around 1/4in. I told the client I would make it right! To do so my plan is to rebuild the base/torsion box. What I'll do differently this time is use glue and I'm going to double up the framing. Here's what I'm thinking dry fit on the ground. I have some liquid nails and I was thinking of using that to adhere the plywood to the frame. I'm hoping this will make a bomber foundation that won't sag. Quote Link to comment Share on other sites More sharing options...
RichardA Posted October 28, 2017 Report Share Posted October 28, 2017 Have you looked at torsion box construction? Every one I've seen has triple the amount of crosspieces, what you have there is just a cabinet or bar top. 2 Quote Link to comment Share on other sites More sharing options...
Popular Post wdwerker Posted October 28, 2017 Popular Post Report Share Posted October 28, 2017 More crosspieces(6) and regular yellow glue( not liquid nails) will make it much more ridgid. Check for flatness and leave for 24-36 hours to dry completely before you put it back on the cart. 3 Quote Link to comment Share on other sites More sharing options...
Alan G Posted October 29, 2017 Report Share Posted October 29, 2017 ^^^^^ That right there will give you the best results ^^^^ Also when you apply the yellow glue you need to spread it out evenly on every surface. Don't just drizzle it on there and then lay the ply on. You are wanting to get the most glue surface possible. Lastly, strength to resist sag mainly comes from the height of a board. A change in height will help reduce sag much quicker than a change in thickness. Quote Link to comment Share on other sites More sharing options...
Elroy Skimms Posted November 21, 2017 Report Share Posted November 21, 2017 On 10/28/2017 at 2:55 PM, wdwerker said: More crosspieces(6) and regular yellow glue( not liquid nails) will make it much more ridgid. Check for flatness and leave for 24-36 hours to dry completely before you put it back on the cart. +1 to this advice I use 6 casters on my 5' x 10' torsion box, only because I don't want the leading caster to get stuck in an expansion joint on the garage floor. The middle casters don't add to the rigidity. More cross members and the right glue will do the trick. -E Quote Link to comment Share on other sites More sharing options...
bushwacked Posted November 21, 2017 Report Share Posted November 21, 2017 wow that is a lot of cutting right there haha. How is it working out this time? Quote Link to comment Share on other sites More sharing options...
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