Slagathor Posted March 30, 2016 Report Share Posted March 30, 2016 I searched for several answers on this, but did not get a definitive answer on the best practice for dealing with tension/kerf closure on a TS rip. The threads that I found had feedback that ranged from: Use a bandsaw to rough cut, then use the TS. Use a bandsaw, then use the jointer to clean up the edge. Use a circular saw. Use the TS, kitty cat... Is there a consensus on the best (or least worst) way to rip cut wood with tension in it on the tablesaw? I saw several references to sticking a wedge into the kerf to keep it from closing up, but wondered if stopping the saw, wedging the kerf, and then restarting the saw with the blade in the existing kerf was the accepted best practice. The specific situation I was in last week: Was attempting to rip a 6' length of 7" wide x 1.125" thick hard maple down to final dimension of 5" wide. Plan was to rip down to 5.25" wide on initial cut, and then make a final rip down to 5". The initial cut got very tight about 18" into the rip. I killed the saw, and then stepped back and realized I was not entirely clear on where to go from there. I did not feel entirely comfortable backing out and starting the cut over (re-cutting into the semi attached closed kerf) and wound up wedging the kerf and restarting the saw. Curious on what the least worst route forward on this would be assuming the operation needed to be done on the tablesaw. Quote Link to comment Share on other sites More sharing options...
..Kev Posted March 30, 2016 Report Share Posted March 30, 2016 You're certainly going to get lots of different answers I'm sure.. In my shop, I would cut those on the bandsaw first and to the final trim on the table saw. I also make sure that the riving knife is always in my table saw. Now, if I didn't have a band saw, I would probably cut it with a jig saw and then trim on the table saw. Point being is that there just no reason to take a chance on the table saw. Quote Link to comment Share on other sites More sharing options...
bradpotts Posted March 30, 2016 Report Share Posted March 30, 2016 I have a micro jig splitter in my zero clearance insert. It comes with a wedge so when the board starts to pinch it picks up one of the splitters and keeps the kerf open. You might want to look into them. Quote Link to comment Share on other sites More sharing options...
Brendon_t Posted March 30, 2016 Report Share Posted March 30, 2016 Imo, that's where the band saw excels. No reason to risk it if an easily viable option is a few feet away. At the first sign that a cut is getting wonky, I kill it and finish the cut on the band saw. I'll then follow at the table saw 1 Quote Link to comment Share on other sites More sharing options...
minorhero Posted March 30, 2016 Report Share Posted March 30, 2016 The most obvious safety feature to try and prevent kickback in this situation is a riving knife or splitter. Those aren't really there as a panacea though. This comes down to a best practices kind of thing and in a situation where you are in the middle of a cut and realize this is happening best practices is to stop the saw as you did then lift the board off the saw and take it to another machine. As others have said, bandsaw or jig saw is definitely the best since their blade cuts in a way that would essentially eliminate this problem. Simply wedging the kerf can be problematic when the darn thing closes up later on and since kickback can happen quickly, its just not worth it to play chicken with a board that is moving dangerously. Quote Link to comment Share on other sites More sharing options...
Chestnut Posted March 30, 2016 Report Share Posted March 30, 2016 I've done the wedge with good results but i only did it with a couple inches left to cut and i did NOT stand behind the board at any time. I don't have a band saw or another tool to complete it so when i get into that situation feather boards and long push sticks come out. Quote Link to comment Share on other sites More sharing options...
Nestor Posted March 30, 2016 Report Share Posted March 30, 2016 When the piece was binding, was the motor bogging down? If not, and assuming you have a splitter in the saw at the time, compare your blade thickness to what you are using as a riving knife. If your kerf is too thin, your piece is getting wedged into your riving knife. You may not have noticed it on thinner material or thinner rips because the wood was allowed to spread. On a thicker piece, it may not be able to spread as easily. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
gee-dub Posted March 30, 2016 Report Share Posted March 30, 2016 As mentioned the splitter/RK should keep the blade from being pinched and let you continue the cut although with more effort than many are comfortable with. If the material is that lively you could have more spoil than those dimension will allow and still get to your desired final dimensions. As to using the bandsaw, this is a good idea but, you would have to know that the material was going to be reactionary prior to making the cut or just always rip at the bandsaw. I rip a lot at the bandsaw but, use the tablesaw for final dimension cuts just as often. If the pinch grabbed my RK to the point where I was uncomfortable proceeding I would stop the saw, wedge the kerf and remove the material. If I thought I could salvage the parts I need I might get the bandsaw blade into the kerf, re-wedge it and make a rough cut. How I would proceed from there would depend on what I ended up with. Quote Link to comment Share on other sites More sharing options...
Llama Posted March 30, 2016 Report Share Posted March 30, 2016 You could also crosscut the piece to rough length before ripping the material. If I see a piece get that wonky, I usually just burn it. Mitigating any future issues in the finished piece. 1 Quote Link to comment Share on other sites More sharing options...
AceHoleInOne Posted March 30, 2016 Report Share Posted March 30, 2016 Yep, if I get a board that has tension enough to causes this trouble. The board is put off to the side. Find another use for it. -Ace- 1 Quote Link to comment Share on other sites More sharing options...
Slagathor Posted March 30, 2016 Author Report Share Posted March 30, 2016 Thanks for the replies... I kind of figured the answers would be all over the map (including trashing the board.) For the record, the saws I use all have riving knives that are correctly adjusted. The cuts were stopped at the point that the resistance started ramping up - the blade/motor was never bogged down and the impingement seemed to be across the back side of the riving knife from the left side of the kerf. Since I generally don't have access to a band saw, I was a bit stumped on the 'least worst' set of options that presented. I think as a best practice moving forward I will continue to make rip cuts on the TS in two phases - an initial rip to within 1/4" of final width, and then a final cut to dimension. Should the cut close up, I will definitely consider a bandsaw or jigsaw if available. If another tool is not available, I will try using a sequence of smaller rips (1/4 to 1/2") on the TS to get closer to final dimension. Or consider a different board per Llama & Ace... Quote Link to comment Share on other sites More sharing options...
drzaius Posted March 30, 2016 Report Share Posted March 30, 2016 Realize that a jigsaw is pretty cheap, so you should just get one so you have it on hand. If you don't have one, then you might be tempted to push a rip that you really shouldn't. Quote Link to comment Share on other sites More sharing options...
Slagathor Posted March 30, 2016 Author Report Share Posted March 30, 2016 DrZ - I have a jigsaw... It is just not always with me where I am working. Hence, the 'if available' comment... Quote Link to comment Share on other sites More sharing options...
drzaius Posted March 30, 2016 Report Share Posted March 30, 2016 Ah... Just curious, you mention the saws you work with. Are you working out of maker spaces? Quote Link to comment Share on other sites More sharing options...
Slagathor Posted March 30, 2016 Author Report Share Posted March 30, 2016 Yes, for better an worse.. At home I have a Bosch jobsite saw, along with the various smaller tools, etc. (including the jigsaw.) For milling or larger operations that I can not handle safely/comfortably in house, I have access to an arts school that has a full woodshop (Sawstop tablesaws, bandsaws, jointer, planer, etc.) The machines in the school are very well maintained (blades rotated for sharpening, etc.) - as long as you check the basics - is the fence square, blade square, etc. The genesis of the question I initially asked was based on searching this site for threads on ripping tension wood, closing kerfs, etc. There were many references in previous threads about just sticking a wedge in the kerf and moving on vs. using a different tool vs. backing out of the cut and restarting on the TS. Those answers struck me as being all over the map. So on a 'going forward' basis - it sounds like the bandsaw would have been the best option overall since I was at the school. At home I would probably just bust out the jigsaw. But since this was the first time I'd really had a kerf slam shut that tightly, it really caused me to stop and scratch my head a bit. Quote Link to comment Share on other sites More sharing options...
Nestor Posted March 31, 2016 Report Share Posted March 31, 2016 Thanks for the replies... I kind of figured the answers would be all over the map (including trashing the board.) For the record, the saws I use all have riving knives that are correctly adjusted. The cuts were stopped at the point that the resistance started ramping up - the blade/motor was never bogged down and the impingement seemed to be across the back side of the riving knife from the left side of the kerf. Since I generally don't have access to a band saw, I was a bit stumped on the 'least worst' set of options that presented. I think as a best practice moving forward I will continue to make rip cuts on the TS in two phases - an initial rip to within 1/4" of final width, and then a final cut to dimension. Should the cut close up, I will definitely consider a bandsaw or jigsaw if available. If another tool is not available, I will try using a sequence of smaller rips (1/4 to 1/2") on the TS to get closer to final dimension. Or consider a different board per Llama & Ace... Your symptoms were just like mine. At first, I played with the fence alignment thinking it was binding between that and the riving knife. I finally figured out my issue when cutting a piece of plywood. When it jammed, I shut down the saw and was surprised to discover that the bind did not release when I moved the fence out of the way. It was then I realized the kerf wasn't wide enough for the knife. Quote Link to comment Share on other sites More sharing options...
Coop Posted March 31, 2016 Report Share Posted March 31, 2016 20 hours ago, bradpotts said: I have a micro jig splitter in my zero clearance insert. It comes with a wedge so when the board starts to pinch it picks up one of the splitters and keeps the kerf open. You might want to look into them. I keep seeing this micro jig splitter and googled it. These two little tabs for $40? I realize everything is relative and I'm not bitchin, just wanted to make sure I was looking at the same things you guys speak of before I buy them? Also, there's not a problem of them coming out of the holes in the insert if pinched by the board? Quote Link to comment Share on other sites More sharing options...
Brendon_t Posted March 31, 2016 Report Share Posted March 31, 2016 2 minutes ago, K Cooper said: I keep seeing this micro jig splitter and googled it. These two little tabs for $40? I realize everything is relative and I'm not bitchin, just wanted to make sure I was looking at the same things you guys speak of before I buy them? Also, there's not a problem of them coming out of the holes in the insert if pinched by the board? Yes that's correct, your posting for them doing the r&d and convenience and them coming out is exactly what they should do to keep the boards open. Quote Link to comment Share on other sites More sharing options...
..Kev Posted March 31, 2016 Report Share Posted March 31, 2016 2 minutes ago, K Cooper said: I keep seeing this micro jig splitter and googled it. These two little tabs for $40? I realize everything is relative and I'm not bitchin, just wanted to make sure I was looking at the same things you guys speak of before I buy them? Also, there's not a problem of them coming out of the holes in the insert if pinched by the board? They also come with the template to put them in your 0 clearance insert.. A friend of mine uses them and likes them, I've used his saw a couple times on some wood that was questionable and was happy to have their service! If I didn't have a RK, I'd be going this direction! Quote Link to comment Share on other sites More sharing options...
Tpt life Posted March 31, 2016 Report Share Posted March 31, 2016 I think they consider that a plus. If they come out because they are pinched, then the board still should not pinch the blade in theory. Quote Link to comment Share on other sites More sharing options...
Coop Posted March 31, 2016 Report Share Posted March 31, 2016 Thanks guys. I've pushed mother natures luck long enough. Tomorrow I'll own a set, or two, 1/8" and thin kerf. edit: one other thing, I always see them on here being used on mc inserts and then I hear where these inserts are the worst as far as dust collection efficiancy goes. Can they also be used on a regular insert? 1 Quote Link to comment Share on other sites More sharing options...
wdwerker Posted March 31, 2016 Report Share Posted March 31, 2016 I remember seeing someone had drilled holes in a phenolic Zero clearance insert to allow airflow for,dust collection. You need the thickness of the ZCI to drill the holes that hold the Micro Jig Splitters. I have both thicknesses and use the thin kerf pro version the most. The orange one that will pull out and ride in the kerf if it closes hard enough works very well, especially in long rips. Quote Link to comment Share on other sites More sharing options...
Coop Posted March 31, 2016 Report Share Posted March 31, 2016 Steve, are the holes drilled into the insert the same size for both size splitters or do I need a seperate insert for each size? Quote Link to comment Share on other sites More sharing options...
wdwerker Posted March 31, 2016 Report Share Posted March 31, 2016 Don't remember but you cut a slot in a new insert then use the jig that comes in the kit to guide the drill for the holes. I am guessing that a wider slot for a standard blade would have a slightly different center line so it might be smart to get 2 ZCI inserts. Quote Link to comment Share on other sites More sharing options...
Coop Posted March 31, 2016 Report Share Posted March 31, 2016 Thanks. I still have the riving knife for the 1/8" blade and will use it with the original insert and will just get the splitters for the thin kerf. Quote Link to comment Share on other sites More sharing options...
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