I recently bought a used Delta 22-650 thickness planer and I've noticed something concerning. After running about five boards through it, they ended up varying in thickness by as much as 0.010". This discrepancy is too significant for me when trying to glue them into panels. I'm curious what could be causing this issue. I didn't lock the height of the planer while adjusting it, which might have contributed to the variation. Also, the boards I used were different widths; could that impact the cutting depth at a fixed feed rate? I didn't experience this problem with my previous smaller lunchbox-style planers. Any thoughts or insights would be greatly appreciated!
3 Answers
I think there could be some backlash in the lead screw of your planer. Different board widths and wood hardness can affect how evenly the cutting head is cutting through. If your planer has a locking mechanism, try using it to see if it helps. The setup might be allowing one side to move differently than the other due to gravity and the wood's resistance.
That variation is pretty normal with thickness planers. I’ve used a ton of them in my cabinet shop, ranging from super cheap to high-end models, and they all have their quirks. Planers can warp wood a bit if the boards have any bow. If you need a really precise thickness, consider using a thickness sander afterward. They tend to give much more accurate results. Your measurements are actually pretty typical!
It sounds like your blades might not be perfectly level, but don't sweat too much about 0.010"—it falls within acceptable tolerances for many shops. Some professional setups aim for precision down to 0.015". Gluing panels can be tricky no matter what, but that slight difference isn't a huge deal and can be sanded out without any major issues.