Thread: Problem With Work Bench (newbie)

Hi Benni,

firstly welcome! It's good to have you here

Do you have any pictures of the problem? Do you mean that when the pieces that make up the top are put together, their edges don't line up? Or that when they are put together, they don't lay flat? Or is it that the base and the top don't line up or aren't square?

Also, what sort of workbench are you building? There are about as many different bench types as there are arguments about which is the best.


Cheers, Mike

Hi Mike,
Thank you for the quick reply.

the pieces at the top and bottom don't line up and when i have it all joined together the whole bench frame doesn't look square.
i don't have a picture but i have a link of the bench im trying to make.

I Had another look the frame and i think another problem might be that the rebate areas arent quite flat enough, maybe some sanding and some chiseling might help.
http://www.mitre10.co.nz/guides_and_...d_a_workbench/

Cheers, Ben

Hi Ben, welcome aboard and get ready to enjoy your time in woodworking.

As for your problem, we probably need a bit more information to work from, as there are a few things that can cause issues.

Is the material for the basic frame all straight, and of accurate cross section dimensions? If the timber is bowed or twisted it can be hard to cut matching components and keep them matching during assembly, so they will tend to pull the frame out of shape. Likewise, if components that should match have different actual thickness (even if they have the same nominal or store label thickness) then they might throw things out also.

When it comes to cutting components, have you selected matching materials for matching components, then laid them side by side to mark them out before doing any cutting. If you say lay four legs side by side, and clamp them together, you can mark one end across all four legs with a square, then measure once to get the other end marked with a tick mark, and mark across the four for the other end. You now have four components marked out at the same dimensions and ready to cut. If you are using a handsaw or circular saw to finish cut them, now is a good time to do so, so they continue to match once cut. If you have a table saw or drop say, I would unclamp them and cut one end off square, then set up the first component for cutting with some form of stop block determining the length, then cut the remaining matching components using the stop block to determine their length (make sure that there is no sawdust jammed between the stop block and component as that will cause components to be shorter than others they are supposed to match). If you cut each set of matching components this way, they should be accurately matched for length. You can then use the same type of marking out techniques to lay out matching joinery etc, so that ultimately you end up with a kit of parts to assemble.

Are you using accurate measuring and layout tools. I have little tolerance for using cheap tape measures for measuring, years ago I was a factory foreman and responsible for cutting materials to pass on to the welders for assembly. One welder bought a job that I had cut back complaining that everything was 1-3mm short. I got my tape out and measured them, all within .5mm, he remeasured and all were out as he said. Compared tape measures, they didn't match. Boss had been nice that morning and bought a dozen new 8m tape measures and issued one to each of us in the factory. Ended up comparing the whole set and no two matched. Boss ended up taking them back to his supplier and buying half a dozen Lufkins at more than twice the price, and a very nice set of 300mm, 1m and 2m stainless rules for the saw department. Solved that problem. The next problem you are likely to encounter is squares, a lot are not truly square, due to either poor quality control at the factory or mishandling in use. A simple test is to take the square, place it on a piece of sheetgoods with a known straight edge, and mark a line on the surface with a fine pencil. Then flip the square over and slide it along to meet the line. If the blade meets the pencil line for the blade length, then the square is actually square, if it doesn't the error between the blade and line will be twice the error in the square. Obviously, if you mark a 'square' line across a bowed piece of material, the line may be tangent to the curve in the region where you marked it, but will not be square to the axis of the material, and any marking out transferred to matching components will have increasing errors as you move away from the curved reference edge.

How accurate is your cutting device? Are you cutting freehand with a handsaw or circ saw, using a circ saw and guide, or using a table or drop saw. Freehand cutting is primarily about technique, but once you involve machinery or guides etc, the setup accuracy of the system becomes critical. Most of the cheaper gear available to hobby users is not accurately set up out of the box, and most has so much slop in the system that proper alignment and repeatable cuts are near to impossible. That one reason why a tradie might have a $900 dropsaw while a hobbyist might have a $100 one, they can't afford the grief that a cheap and nasty unit can give them. Not saying that you must have the latest and greatest, just that you need to be able to measure the accuracy of the gear that you have to identify problems that it might cause, and either adjust the machine or your work process to minimise inaccuracy and maximise consistency.

Sorry not trying to scare you off, just trying to point out a range of issues that can cause the problems you are having. Come back with some more info if you can, and collectively we can try to identify the source of your issues and ways to correct them.

Hi Malb,
Thank you for the informative reply.

The timber is is all straight
i havent laid the wood out to to mark them, i just used the tape measure
, i have got a whole new bunch of wood i will lay them all together to do the marking
The tools i have are the cheapest available, iam now considering upgrading,
iam cutting with a circular saw and a mitre saw.


i will have a play around with it again tomorrow and let you know how it goes,


Thanks for the input guys!
much appreciated


Ben

Welcome to the forum Ben.

Hi Ben, I am a slow but fairly thorough typist and the stuff I put up earlier took a while to prepare. You posted a link to the worksheet you are working off while I was preparing it.

Having looked at it and the post surrounding it I have a fair idea of what you are making and the issues you have.

You say that the ends don't appear to be square when you try to assemble them, but your timber is straight. For the design you have, having matching components with identical cross section dimensions should not be critical, but a lot of benches have a full length 'foot' at the base of the ends and if these parts are not matched in height, and you have not compensated for the problem, then the mismatch will also show in the height of the ends, and the bench will slope from one end to the other. Not an issue for you, as your design does not have feet on the ends and the end rails size is not critical as you match the leg lengths and align the rails to the top of the leg so that should give you a level frame.

Re not being able to square the ends, I suspect that the issue may be that the components are cut slightly off square, either because they were marked out slightly off square due to a faulty square, or cut slightly off square because your mitre saw is out of square. Remember that if something is marked out/cut out of square by 0.5mm on a 90mm wide component, when you attach a 900 long part tight to the mark out/cut, the error at the other end of that component will be 10 times greater, or 5mm, which is more likely to be more noticeable to the eye than the 0.5 mm of the original mark out/cut. Therefore I would check that the square you are using is accurate and if it is, use it to check that the blade and base plate of the circ saw are at right angles, and that the mitre saw blade is at right angles to the base plate and fence. You may also need to provide chocking for your components beyond the mitre saw base to ensure that components rest evenly on the saw base.

Do you understand the part of the project guide about measuring across both diagonals of each end to check for square when assembling the ends? This will only work if the components match in length properly. If all of the components match properly, and the two diagonals are equal in length, then the assembly has to be square. However if the component lengths don't match somewhere, ie one leg is shorter than the other or one rail is shorter than the other, the assembly has to be out of square to match the diagonals so check the legs for equal length and the top and bottom rails for equal length first, then do a trial layout and check the diagonals for equal length.

While you may have more timber available, you should be able to reuse what you have. You just need to get 4 legs with identical lengths, and two top and two bottom rails with identical lengths. It doesn't matter if the legs are all 10mm shorter than suggested in the guide, or the rails are all 10mm shorter than suggested, it just means that the bench frame will be slightly lower or narrower than they suggest. So I suggest that you check everything on the tools and parts you have to try and find a source of the error, correct it, and trim any components where you don't have a fully matching set so achieve closely matched components. Then temporarily assemble each end frame and check for square by measuring diagonals, and finally assemble permanently.

Hope this helps.

Good Morning Ben

Firstly, welcome to the Forum.

Secondly, write one hundred times -
"I will never ever, buy crap tools again."
It is the biggest mistake I have made, and repeatedly.

My first bench measured accurately, but the frame did not look right. And I did not know enough to diagnose the problem. It eventually dawned on me that the components were parallel to the floor, but the concrete was neither flat nor level. It is now my secondary bench and I still chock it to stabilise it, and the top is still a little warped.

I wish that I had had something like this Forum when I was starting out - would have saved a lot of pain and $$$'s. Also, remember that beside the excellent advice that malb is giving you, there are many other members monitoring the conversation and they will step into the debate when and as they think appropriate.

Enjoy creating sawdust !



Fair Winds

Graeme

Hi Guys,
Thanks once again, all the adivice i have been given is amazing and is making me understand why this is going wrong, i am currently offshore and i will be home in 3 weeks, so fingers crossed i will get right back into the garage and get that bench up.
i will keep you guys posted how i get on and will upload some pics for you all to see

Thanks

Ben