I've started using fixture plates more and more. If I want to make more than one of something fixture plate more easily allows me to use the full work envelope of the machine. In fact, in excess of the work envelope of the machine in some cases. Everybody's application will be different, but I use a lot of standard width aluminum flat bar. You might think that would be perfect in a vise. In fact for years I thought so too. In order to cut two pieces I would mount two vises, and use G54,G55 work offsets. It works very well, and halves the number of tool changes to do a job. I've got a stock desing 2x3 inch mold I make fairly often. I could put two presized pieces of stock in the vises, get my offsets, and cut a complete mold in one shot. Maybe I could cut 2 molds if I felt comfortable putting two pieces in each 6inch vise, but I just don't trust a vise to clamp both pieces well enough for all operations. As you may be aware flat bar varies in width and thickness. Usually from over size to just barely over size. I supposed if I did MORE prep work that would be less of an issue, but then its more prep work. More time I am not at the computer catching up design work.

My solution was going to a fixture plate. So far for the Tormach I have made 2 of them, and plan to make 3 more. It was a lot of work to get everything dialed in and measured, but now I have a 2D cad model of "my" Tormach mill table. I set two alignment pins in the bottom of the plate, flipped it over and to machined place. I pull the pins against the center slot of the table and clamped it in place. Next I pocketed out countered bored bolt holes for the plate to set button head bolts to lock it in place. It gets bolted down, and a register mark in machined the exact center of the machine travel. Finally machine a partial flat on each end for using a stop to take one plate off and put another one on. At this point its a fixture blank.

My first simple fixture plate is with slots (and clearance \underneath) for 2 inch wide flat bar. I can machine every part of 4 of those 2x3 mold plates in one setup. I just drop a long piece of flat bar in the slot, and its held by a bunch of edge clamps. Each clamp moves individually when its tightened so its firmly clamped at several points. All the features are machined and then its split with a semi slotting operation. I don't worry about cutting all the way through either. There will still be plenty of support for stock in the future. I made that fixture plate with 3 such slots. In one setup with 12 times fewer tool changes I can machine 12 parts to make 6 complete molds.

I made a similar one for two pieces of 4" bar stock. I've used it several times to cut 4x6 mold plates 4 parts at a time. I mounted a gage pin to fit my register, but so far repeatability when I set the plates has been as good or better than the repeatability of the mill's homing process. I use the register atleast the first day when I set the plate anyway.

Then I design jobs around the fixture plate when cutting multiple parts. No more need to keep track of multiple work offsets if I just start with a slightly over length piece of bar stock.

I have wished I had a vise on the machine a couple times, but I do have 4 other machines in the shop that still have vises mounted on the table.. Five if you count the little toy mill drill. The Hurco still has 2 8 inch vises dialed in on the table. Its got both cut in place steel step jaws and soft step jaws labeled for each vise.

Fixture plates are not as useful for single one off unique parts or repair jobs, but for small scale production they really helped me juice up my productivity. I'm seriously considering them for my two quick change fast spindle machines.