Is it normal on the open Builds extrusion to be to long? I purchased 2 20x60 extrusions that were suppose to be 1000mm long and they were 1003mm is this normal?
It's normal. If you want precision down to the millimeter you'll have to find someone that does it and probably pay extra. You'll always get at least the length you order plus a few millimeters.
Good to know now. I will not be ordering extrusions from Open Builds again. Atleast everyting I have ordered for my shapeoko CNC from inventalbes if they say it is 1000mm it is 1000mm. What a waste of money.
I have never ordered from inventables but looking at the prices they are a few dollars more so maybe that is why the extrusion is the exact length. I personally hate making the cuts because they are never square but I now have a bench sander to fix that. It was actually a pretty good excuse to buy the sander since I've wanted one for a while I'm pretty new here but if you build something cool then post it up so others can see and get ideas from it. Good luck with your build!
Here you go.. I posted up my Build log so you can see the progression of my CNC. http://www.openbuilds.com/threads/my-cnc-build.1276/
Unless you pay for precision cuts when you order material it is +x -0. x is often 1/8" to 1/4". Most of the time I tend to order an inch longer than I need so the cut is a bit easier on the saw if it is for personal use. When ordering for business every inch cuts into the profit margin so we order to length and trim the small excess square.