Straightline Rip Saw Kickback Concerns

A discussion of prudent safety precautions to take with a straight-line rip saw. July 18, 2008

I'd like to add a straight-line saw to my shop but I am concerned about the safety. I've heard that these saws can kick back scraps the size of broom stick handles like a spear.

The newer Diehl straight line rip saws have two sets of anti-kickback fingers that drop down from the top and flip up from the bottom. I presume that the new Oliver saws do also. Are these fingers sufficient to prevent lumber kickback? How often does off-cut lumber kick back?

I know that you need to stand off to the side of the blade when feeding lumber into these saws but I want to know if there is anything else to consider when planning a saw like this into your shop layout. Somewhere along the line I heard that the saw should back up to a wall or something to minimize people walking behind it.

Are there any other safety issues to look out for? Also, I know these saws are great for generating a first straight edge. I need to be able to change dimension about as often and randomly as you would for the oddball cuts you'd make on a utility tablesaw. How effective are straight-line saws for parallel ripping? (All the rips would also pass through a S4S planer after this station).

Forum Responses
(Solid Wood Machining Forum)
From contributor G:
I have had a slr for 5 years (Deihl). We have never had a kickback in the thousands and thousands of bdft we have cut. It can and does happen but not here, yet. The danger zone of a slr is the same as tablesaw. Use common sense and like you said stand to the side.

I have heard a bottom mount blade is safer than a top mount. I don't know for sure how true this is. It would be hard to back the saw against a wall if you want any kind of in-feed or out-feed distance at all. An slr can produce a straight edge (especially with a laser to project the line of cut) and just as effortlessly rip to width using it's rip fence. These saws are very fast and accurate. What you are proposing to do with your saw is exactly what they do best. In my opinion they are safer than a tablesaw with or without a feeder.

From contributor D:
You have it right. Kickback can happen, so I hear but I haven't seen it in over 200 truckloads of lumber. We processed for molders with a couple of Diehl 52's and never had a problem. Top and bottom fingers are adequate - keep them in good shape. The worst was slivers getting stuck up in the rollers or between the blade and the tracks. Shut it down, let the blade stop and remove.

Situate the saw to limit traffic behind it, or use a heavy rolling screen behind just for common sense. They are fast and accurate. Get a good laser and take the time to align it properly. The fences set fast and secure, so accuracy is up to the operator, but it is not difficult - not much of a learning curve. Its more intimidating than anything, especially when those tracks grab the board and send it through at 75' per min.

Ask yourself whether you need glue line rip or just straight line for the molder. I was skeptical when I heard you could glue right off the saw, but was a believer in no time. I would recommend a conversation with the folks at Diehl, even if you are looking at used. Support like no other company I have ever dealt with. They'll give you all the info they have on used saws out in the world, so you can establish relative value and get a handle on costs to replace bearings, chains, etc.

From contributor X:
Having seen the results of one incident, I would recommend that the operator use a leather apron to protect his privates and whatever else it could cover without being a pain.

From contributor H:
Contributor D brought up a point about gluing from a SLR. Diehl saws can be set to cut a "sprung" joint or straight. Be sure you understand this when purchasing. If you buy an import I don't think this is an option. My saw does not cut a "sprung" joint. I glue from the saw and get better results than any other method I have tried. I have had my saw spit back small strip waste pieces, the ones that are feather thin. I changed blades and have not had a spit since.

From contributor T:
We just recently got the "little" Extrema with the overarm blade. For anti kickback, it has two rows up top and one on the table in front of the chain. The laser took a little bit of trial and error to dial in, but not hard at all. Some masking tape on the floor 10 ft away with test marks was the hot ticket.

It is easy to change fence settings, and parallel rips work pretty well - consistently within 1/16" over 10 ft. I imagine that you will want to leave it overwidth to S4S anyways?

I have been shopping for a new blade, as we got this saw used and the current blade has combo style with high tooth count. Almost polished edges, but maybe too burnished for gluing some harder woods.

Like you, I've been allocating wood early in the process - it really helps to get good yield and quality right where you need it. We broke the saw in on ripping down a unit of cherry for 3 big kitchen's worth of doors. Now I'm wishing for a Doucet return conveyor!

From contributor U:
One of the things that seems to escape most shops is that this is a piece of equipment that needs to be maintained and adjusted from time to time. Although the level of adjustment that it needs depends on its age and is minimal at best, most shops look at the Rip Saw as a "Turn It On and Go!" type of tool.

Most of the incidents involving saw kickback involve dull anti-kickback teeth, thin lumber being run through an improperly adjusted saw, a feed chain that is exceptionally worn, or even a combination of any of the above factors.

Just make sure the manufacturers recommendations regarding adjustments are followed and that a strict maintenance regimen is adhered to and all should be fine.

Oh, and the final bit of useful information: dont stand in front of it as lumber is moving through, even if it is a brand new saw. As the old Karate saying goes "The best way to avoid a punch is to not be in its path".