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weinig powermat 1500 cut-stock tolerances2/12
The company I work for has 2 weinig powermat 1500 moulders and we are concerned about our cutstock tolerances. We make our own cutstock in house and I was wondering what a how close we have to be to exact sizes before we feed it into the weinig. Any thoughts?
So for example if we had cutstock that was 2" wide 1/2" high, what would the tolerances need to be? 2" +/- ?.
First question is what are using to prep your blanks? Straight line rip saw or gang rip? Is the material really straight after that or does it have some crook in it from tension being released? I work with a lot of wood that once it's cut from a larger board, quite often it will have some crook. That means I need a little extra width to allow the molder to cut a good part. I typically go 1/4" over on width, I've heard of certain places that can go down to 1/8 or even 1/16, to me that's a little to close and may loose some lineal footage trying to save a nickel. What is your end product? Are you milling crown that has no give at all in a narrow piece? Flooring? That has some flex if your cutting tongue on the left, a little narrow on a few pieces won't kill anyone.
Our end products are window and door stile and rail parts. They have to be pretty much right on. I'm pretty sure that our bow tolerance is 1/8" over 2' length. Most of our profile shapes have to be within +/- 0.015" Not sure how much crook our cutstock has right now, but I know that it is gang ripped. I'll take some samples today and see how much crook is in them.
It is typical for 1/4" over on the width and 3/16" on the thickness because most people purchase four quarter 15/16" hit and miss lumber for 3/4" thickness mouldings.
Some mills, like Dustin mentioned mill less off each side and top, but they take the risk of reducing yield, which can be costly, you know, the old walk, "over a dollar to pic up a penny" slogan. Keep in mind the metal feed rollers that come standard on the moulder have 1/8" depth of tooth mark (penetration) that must be removed by the top cutter heads, you could use the knurled 1/32" penetration, or rubber rollers but you would sacrifice feed pull power on the machine, along with the added expense. You will have times where other rollers may come in handy, but try and stick with what comes with the machine, they work better than ever with the new gullet design.
If you set the in-feed fence at 4mm with 1/4" over-sized lumber, it should take out any bow that's 1/8" or less and still cleanup the edge. I have attached an article that may be of use to you with orientating of the lumber as you are feeding before it goes into the moulder.
Hope that helps some All the best Russ @ MR
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