Glue Line Rip Saw

Will a straight-line rip saw make cuts clean enough for glue joints? November 18, 2006

We are researching the purchase of a straight line rip saw. Although we are well versed in woodworking machinery in general (beam saw, CNC PTP, PLC controlled edgebander and widebelt sander, etc.), we have very little knowledge as to what makes a rip saw work and what makes a good one as opposed to a bad one. This saw will not see all day, every day use. It'll be more for busting up lumber for stiles and rails. Solid lumber for wood tops, etc. We're looking for a glue line rip and we're not looking for gang rip capability at this time.

Forum Responses
(Solid Wood Machining Forum)
From contributor D:
I have experience with the older Diehl 55 and similar models. Diehl will still supply parts and service for these iron workhorses. The worst that can go wrong is poor maintenance and not swapping the feed chains as recommended. This results in uneven wear and loss of glue-line capacity. About $6k in parts and three days labor, but you may have to wait for the parts to be made.

With new machines, you want to get it in writing that the machine will do glue line rip, and buy from a real industrial machinery dealer. With used, talk to the manufacturer and listen to their advice, and plan on doing a big rebuild. Diehl has new saws that have a smaller footprint and will still do glueline. They will be at Atlanta.

From contributor J:
After a few months of use, the small Taiwan Oliver has worked fine for us. The compact size was our reason for this choice. We have ripped some 5000 lineal foot quantities and it's easier than a table saw to rip just a few boards. This saw will not do the hollow glue joint, so we still do critical glue joints with the Martin jointer. It's fine for what we call millwork glue-ups, like cores or paint grade work. The cut is straight, but I can see the slight glue line between the boards. Maybe we need a better blade. I think reconditioned American iron might make a better joint and can be bought for less than these imports.

From the original questioner:
Contributor J, did you get a more powerful laser for your saw? If so, which laser did you get? You say it won't do a glue line rip, so you do critical glue lines on the jointer. Are there other machines that will give a glue line joint? Does anyone have experience ripping stuff like MDF or plywood on a rip saw? It's probably not much of an issue for us, as we can do it on our beam saw, but thought I would ask.

From contributor J:
Last time I talked to the guys at Oliver, they had a better laser but were still working on a mounting bracket for the small saw. In the meantime, we took contributor D's advice and turned the lights down when straight lining. I will call them this week to see what's up with that.

I will try to explain myself a little better about the glue joint. The 4910 is at the low end for a new saw, about 10K. 95% of everything ripped in our shop goes through the S4S machine and that produces a straight glue joint. The 4910 also produces a straight cut, guaranteed up to 7'. From what I have seen, this is relative to the flatness of the timber. You can get a straight cut on 12' timber that is faced and planed with this saw. Send a cupped or twisted board through, and the cut will not be straight. After surfacing and sanding when gluing off the saw, I can see a slight line between the boards and when gluing off the jointer, I don't see this line. To be fair to Oliver, a better blade would probably eliminate this. We have been using a Leitz 60 tooth rip blade. The other issue with gluing is the hollow or spring joint. This is where you see a slight gap in the center of the boards before clamping pressure is applied. In dry Colorado, this is necessary, especially on large tables or tops to eliminate end splits. Our Martin jointer has a quick table adjustment to do this. I know the older American saws have an adjustment for the spring joint. Maybe someone doing this will jump in and tell us about it. A lot of high end furniture makers use Mattison or Diehl saws for table glue ups. For cabinet door panels, the 4910 should be fine.

As for ripping finished plywood, I don't think the SLR is a good idea. Ours leaves a little oil from the chain on the down face. Some of the saws leave dimples. For hanger strips and nailers, probably okay. All this said, the 4910 saw was better than expected and a night and day difference from ripping with a power feed table saw. For serious glue joints, the old iron or even the bigger Oliver are worth looking into.