Duplicate width cuts on a shaper?

[David Nelson1]

I have to make a second run for my flooring project this was posted as tip for the T/S:

http://www.sawmillcreek.org/images/misc/quote_icon.png Originally Posted by Rick Lizek http://www.sawmillcreek.org/images/buttons/viewpost-right.png (http://www.sawmillcreek.org/showthread.php?p=2306455#post2306455)
Take the original piece and set the fence about an inch or so wider. Put a piece of scrap on the left side of the original and rip the scrap piece. Remove the original and move the scrap to the fence and place the piece you want to match to the left of the scrap. Rip the new piece and it will a perfect match to the original without even measuring.

I was wondering how well this technique would work for T/G profile work?

[Peter Quinn]

Nothing wrong with different methods, but I've always used a test piece, dial calipers,and a few actual shaper passes to match previous runs. You have to match the height and width. If you run your groove first on a split fence, your tongue second off of a back fence, nailing the exact width is straight forward. Only real issue is the woods equilibrium. Say you milled 4" flooring in January, RH is very low, wood is contracted about as low as it goes. Then you take a piece of that in late summer......RH now much higher. Measure the face.....a little bigger. Wood really does move. It's important to match an actual sample of the original flooring if you will be mixing old and new boards in a new installation, and to have them as acclimated as possible to the same RH would be ideal.

[Rod Sheridan]

Nothing wrong with different methods, but I've always used a test piece, dial calipers,and a few actual shaper passes to match previous runs. You have to match the height and width. If you run your groove first on a split fence, your tongue second off of a back fence, nailing the exact width is straight forward. Only real issue is the woods equilibrium. Say you milled 4" flooring in January, RH is very low, wood is contracted about as low as it goes. Then you take a piece of that in late summer......RH now much higher. Measure the face.....a little bigger. Wood really does move. It's important to match an actual sample of the original flooring if you will be mixing old and new boards in a new installation, and to have them as acclimated as possible to the same RH would be ideal.

Agreed, including the relative humidity aspect.............Regards, Rod.

[David Nelson1]

Thanks guys! Peter that was how I was heading just thought that there might be a better way.

[jack forsberg]

you really don't need to mach width on flooring to a fine degree you just can't start in mid row with new stock on old.