and three quarters of commercil frames being chopped and the rest made in house from raw timber
is it important to measure art or matted art before frames are assembled or does one just double check the measurments on the job sheet are close enough and hope the frame fits when made
How many people are involved in the layout with the customer, the actual typing up (or printing out on a POS program) of the work order, and the actual work done on the materials that are sized to create the customer's finished frame package?? It seems that the more people involved in the layout process and cutting of the materials, the more opportunities there are for either a mismeasurement or a wrong number being entered or something being misread creating a wrong measurement in the end. Therefore it is imperative that you measure the art work yourself to ensure that everything is now on paper in the same dimensions as it started out. I would NEVER depend on someone else's measurements if I weren't the one who personally measured and made up that work order and, even THEN, I would rarely trust myself!
and should the glass/plexi be cut to the frame size or the job sheet dimentions?
Now we are getting into the questions of "the chicken or the egg"! Are the job sheet dimensions correct?? If you are personally convinced of this, then the frame has also been ordered correctly and the measurements won't change on that item. In this case use either the job sheet (work order) measurements or the frame to cut your glass/plexi, backing board, mount (mat) board, et al. If the frame was ordered to the same dimensions as the job sheet dimensions AND you have already ensured that the dimensions ARE correct, it really doesn't matter which you use (frame dimension or job sheet) to cut the glass to fit, does it??
and when the glass and or mats are fitted should they be tight or loose and if tight is it ok to jam them in and if loose hope the pins holds it in place so it doesn't move around?
Over here frames are traditionally cut with a 1/8" allowance (1/8" bigger than the actual dimensions) to allow for expansion and contraction of the contents of the assembled frame. If your chop facility isn't doing this you can request that they do or simply add a small allowance to each dimension to give some wiggle room in the frame. I would never jam the contents into a finished frame!! You are simply asking for trouble doing that. Follow Rick's advice and you will have very few times when you will have to shim up a frame package.
As Rick stated, measure twice, cut once. That may be a cliché but it is a good guide for minimizing mistakes when more than one person is involved in the process. I have operated a one shop for many years and I still made many mistakes all on my own without anybody else involved!!
Framerguy