Glue-Line Ripping Versus Ripping for Moulder Blanks
Thoughts on the equipment and technique required for smooth accurate glue-line cuts, as opposed to rough cuts that require further dressing before use. February 16, 2014
Question
I'm looking for a really good rip blade with a good heavy thick plate. It's going on a 3hp single phase Ppowermatic 66 table saw, 10". Mainly I'm looking for low resistance when feeding 1-1/8" soft maple (most common, though sometimes thicker). This is for ripping up door and faceframe stock to rough dimension before feeding into a small moulder.
I'm also searching for the best miter saw blades for a Pistorius double miter saw. The machine takes a pair of 12" blades. When I got the machine it had two 12"/80 tooth FS Tool blades on it. Good blades no doubt, and they're sharp, but the plates are apparently too thin because when mitering maple the cut deflects through the thickness of the work piece, leading to open miter joints. The Pistorius has two 3-phase 1.5 HP motors.
Forum Responses
(Cabinetmaking Forum)
From contributor X:
As far as the rip blade goes I use Amana's 20 tooth industrial blade. It is very aggressive and heavy duty. I would only use it with a power feeder though because it is nasty.
From Contributor E:
First, what you are describing is not glue line ripping but ripping for moulder blanks. Contributor X's recommendation for a 20 tooth blade is good. It will give you the low resistance you're after. For glue line rips you'll need a 36 tooth triple chip blade and there is a lot more resistance as well as the need for more hp to feed. As for your miter blades, see if you can't send them back to FS Tool for sharpening and for them to take a look at. The teeth should be cutting evenly without deflection, not sure a thicker plate would help.
From contributor Y:
Three hp seems really weak for ripping much. You will need an aggressive rip blade with few teeth. We've been happy with Leuco blades on the SL rip saw and panel saw. Use FS blades on the Omga miter saw. The trick on cutting perfect miters is controlling the work so it can't move.
From the original questioner:
I realized after I posted that I had confused glue line rip with fast rip. Fast rip is what I need, so I'll keep to the 20 teeth. I'm hunting for a rip saw but don't have one or the space for one at the moment. So the little Powermatic will have to do for a bit longer.
The Pistorius double miter saw currently has the 12" 80 tooth blades and they feel sharp to me. They are not terribly dull though. I've associated the vibration that leads to less-than-perfect mitered ends to thin plates which are prone to vibration, but I'm no expert. I've dialed back the feed speed on the pneumatic chop and this doesn't seem to help much. I guess for the modest cost I'll have them sharpened and see if it goes away.
From contributor Y:
In your heading you say glue line rip. I don't think you will find your 3hp saw capable of running a GL rip blade. Those blades inherently take more power because of their edge shaving sort of operation. Additionally the work has to be very well controlled to produce a GL quality rip. We glue panels directly off the SL rip saw, great time savings.
From contributor D:
Forest blades do well on cabinet saws. If freshly sharpened blades don't cut well on your miter, you may have something else going on with the miter - not holding material tight, bearings going bad, something is loose.
From the original questioner:
The miter has pneumatic hold-downs on both sides of the cut and is in overall cherry condition. Everything seems tight. I will pull the blades out and see how flat the plates are, and then have them sharpened for good measure and try again.
From contributor X:
I would also check to see if the arbor hole is the correct size. I had a blade on my Omga that was too big and caused excess vibration.
From Contributor O:
Molder blanks are produced on a self-feed ripsaw or gang rip for a four (or more) head molding machine. They do not require glue line edges. Glue line ripsaw refers to the auto feed rip saw that can rip thousands of board feet a day, at 30fpm or more, and all of it capable of being glued for width because of the straightness of the cut as well as the quality of the cut. It is not reasonable to expect to be able to glue off a tablesaw, no matter the blade, unless of the very lowest quality. An overhead profiling machine is not a molder, despite the loose language. It is a single side profiler, not a molder.
As for the Pistorius miter saw - go to Pistorius and buy what they recommend from them. Heavy plate is not always the answer. They have done the research and know what makes their machine perform best. Then find a saw service that can help you keep the saws sharp and performing at their best.
From Gene Wengert, forum technical advisor:
Although he does not need a glue-line quality surface, as stated, I might add to the discussion about ripping and gluing that gluing a sawn, ripped surface is commonly done throughout the industry. The key is the sides of the teeth, as it is the sides that are preparing the surface that will be glued. Preparing the sides of the teeth is called side dressing. Some saw shops do this well, but others do not. A second key is to have enough power to have a good feed rate to avoid heating the wood and destroying its glue-ability. A stiff blade is also important, as the edge must be flat and true.
From the original questioner:
Gene, can you elaborate or direct me to more information on side dressing? I will have to ask my sharpener about this. In my experience wobble and vibration is all too often a problem with various saws in the shop, and I've usually attributed this to lack of plate stiffness?
From Gene Wengert, forum technical advisor:
Wobble can be due to an un-stiff blade, heating of a stiff blade, or poor tensioning of a large blade as well as bad bearings. Any place that sells sharpening equipment will have machines for side dressing.
