Blade Kerf and getting the needed kerf in the wood?

[Jon Rista]

Don’t try to slide the board, instead set up a stop block for the first cut then add a shim of the proper thickness between the stop block and the board and make your second cut. Since the blade will tend to deflect when only trimming off make sure you have a sharp blade and cut slowly. To determine the thickness of the shim required divide the amount to be removed by the cosine of the miter angle.

THANK YOU! This was what I was looking for: COSINE OF THE MITER ANGLE. I didn't think it would be that simple...but I was hoping it would be. I am already set up to do this. I just needed a simple way to determine the thickness of the shim. I haven't slept in a week here, so, doing any trigonometry to try and figure this out on my own here, wasn't going to happen...

I did pick up a full kerf blade. It will just make the process easier and faster here, as the 5/64" blade is nowhere to be found now. I have a bunch of things to make, and this blade is just a slight bit wider than the inserts, so it should work well for the use case.

When I first tried celtic knots I did the partial cut as you are talking about but when inserting the inlay it would scrape off most of the glue making a poor glue joint. I then tried cutting all the way thru, but that presented the problem of how to maintain alignment while the glue cures. I have a photo of the gluing fixture but this appears to be the wrong time to send an Email to myself to get a .jpg file onto my laptop computer. The point 2 is exactly what will happen if the insert material is not the same thickness as the saw kerf, I know because I tried to use a thinner insert. I have the ability to make insert material to the exact thickness required, however I then had the bright idea that the insert should have the same grain orientation as the primary wood and that may be a method that you could use. To adapt my method to a table saw attach a board to the cross cut guide that is wide enough to not get cut off then clamp a stop to the end of the board and adjust for the required thickness. The picture will probably get through some time tomorrow and I will send it then.

Aye, I head you about it squeezing out all the glue. Someone on another forum said they will usually shim the blank with a couple thicknesses of paper, or thin cardstock, to widen the kerf just a bit to allow for the glue. This saw blade I picked up is just a smidge wider than the 1/8" stock (which I did not cut myself, I can reasaw, but I do not have a thickness planer, so I buy my microlumber from woodcraft or rockler most of the time. Its not exactly cost effective...but, not only do I not have the funds for a thickness planer, but I also have absolutely nowhere to put one even if I could afford one. So the stock is as thick as it is, not much I can do about it.) If for whatever reason this blade still isn't leaving room for glue, then I can use that thin cardstock tip.

 

[Jon Rista]

Are you not cutting your own material to fit the kerf?

See previous reply.

 

[Mike Selser]

So, I have been thinking about doing this. My main blade, which is about 3/4" wide and has more than your usual number of teeth, leaves saw marks on the surface, which are enough that, I think I would have to find a way to chisel that smooth first. I have other blades, most resaw, one a 1/8" blade for doing curving cuts. I can't imagine the resaw blades working well with these smaller pieces of wood. The 1/8" blade....I don't know if I could keep it truly strait.

I'm curious, what kind of blade do you use for such work? If I could find a blade that did not leave notable saw marks and I could cut strait with, I'd give this a try. I have a Jet JWBS-14sfx, 116" blades.

By far the best blade I have found is the Lenox Diemaster 2. The blade I use is 1/2” x .035”, 3 tpi. Your bandsaw needs to be set up properly and you need to feed the stock slowly and consistently to get a smooth cut. I get glue ready surfaces when cutting veneer but not sure it is smooth enough for a joint that would be viewed edge on. That’s why I suggested finishing up with a disc sander or hand plane.

 

[Brian Gustin]

You ever heard of a digital caliper? I'm pretty sure it is capable of measuring 128ths, as I have pretty reliably thick 1/64" thick veneer, and the 1/128 measure on my calipers is just about half that. You think its not possible to measure as 128th??

Yeah- I have seen 128th's measuring tools, but more commonly once you get down to sizes that small, they've already gone to decimal (10th's, 100th's, 1000th's 10000ths) - 1/128 of an inch is a tad under .008" I HAVE seen digital calipers that read in 128th's but those are often the cheapo chinese makes on Amazon and as mentioned, once we're talking increments that small, might as well move over to my Starrett and start measuring in thousandths... I never saw much point in measuring that small with wood anyway , since wood moves and even a small piece can move more than 1/128th of an inch just from humidity changes.

To other points: The only reason you need a specific size of blade kerf when doing Celtic knots is when you are not doing thru-cuts , and generally in that case I'd say you'd go by the saw kerf and then cut your filler strips to the width of that kerf (as mentioned, thin strip jigs do the trick nicely as long as your saw is set up properly with a sharp blade) Me, I used to do it that way, I'd cut the inserts just a hair THICKER than needed and then hand sand (or hand plane) down to a nice slip fit into the kerf - It helped that I was using a fresh brand new table saw blade so it didn't leave very rough edges in the kerf... But then as I said, I stopped bothering with those designs since they were way more work than what they were worth, and there were much easier and more popular designs and forms to do.

*edit* Huh, wow - in the time it took me to type all that it appears you already found your answers, so.. Moot point, I guess.

 

[Jon Rista]

*edit* Huh, wow - in the time it took me to type all that it appears you already found your answers, so.. Moot point, I guess.

I'm confused...there was an 8 hour gap between my last post, and yours? I mean, a day plus since the answers were actually provided? I don't really understand this comment...

I am not really sure why so many in this thread are latching onto the 128ths thing. Let me just simplify: I have 1/8" thick inserts, from boards I bought pre-cut and pre-planed, for another project I abandoned. They don't fit the kerf my blade cuts naturally. Doesn't matter if its 3/32", 13/128", or 25/256"... The inserts don't fit. That's all that mattered, the inserts don't fit. The jeers about how I am measuring, are just childish, and to be perfectly frank, I don't quite understand that in a community of a bunch of grown men. Anyway...

The point of the thread was is there a way to adjust the blank being cut, just the right amount, to widen the kerf with a thinner blade by making multiple cuts? I knew there was a way to determine it, my brain just wasn't having anything to do with math the last week. Well, DID get an answer to that, thanks to Mike Seiser. I may return the full kerf blade here, if I am able to get sufficient cuts with my existing blade. That was the help I needed. Thankfully, one of you understood the question and provide a useful answer without any of the rigmarol over whether my measurements were accurate or not. Thank you much, Mike.

 

[Jon Rista]

By far the best blade I have found is the Lenox Diemaster 2. The blade I use is 1/2” x .035”, 3 tpi. Your bandsaw needs to be set up properly and you need to feed the stock slowly and consistently to get a smooth cut. I get glue ready surfaces when cutting veneer but not sure it is smooth enough for a joint that would be viewed edge on. That’s why I suggested finishing up with a disc sander or hand plane.

Thanks. I found this in over a 12' length. Not sure if they make one that would fit my bandsaw. Is this a wood cutting blade, or a metal cutting blade? I actually do have a metal cutting blade, its a Lenox "Classic Bimetal", has 10/14tpi. I originally bought it to help me cut unruly materials like trustone or inlace acrylester blanks. Brittle, and they were tough to deal with when the blade had fewer than about 10 tpi. Currently, my bandsaw is set up quite well for this blade. IT does not waver, and all the guide bearings are about as tight as I can get them without unwanted contact with the blade. The distances are 1/16" or less for all guides. The feed rate with woods, though, has to be very slow with this blade, it does not cut fast or even at a moderate speed. The most I generally use it for with wood is to cross-cut pen blanks down to size. I used to buy these "bricks" of trustone, usually 1.5x1.5" or 2x2" around, 6-7" long, and I would rip them down to 3/4" around segments, or smaller pieces for segmenting. The blade works well with those hard, brittle materials. It actually works fine, generally, with wood...it does leave sawmarks, but, really, the only issue is the need to maintain a very slow feed rate. I guess, I'll just give this a try with some scrap wood, and see how accurate, and strait, I can get the cuts. Maybe this blade will work.

 

[Brian Gustin]

. Let me just simplify: I have 1/8" thick inserts, from boards I bought pre-cut and pre-planed, for another project I abandoned. They don't fit the kerf my blade cuts naturally. Doesn't matter if its 3/32", 13/128", or 25/256"... The inserts don't fit

That was sort of what I was aiming for originally - Was there some reason why you could not just sand/plane/whatever the INSERTS to fit the kerf being cut? As opposed to trying to cut a kerf to x width. Not a criticism in the least, just curious if there was some reason that the inserts could not be "shaved" down... which would save needing to get a precision cut kerf?

And lastly I wasn't making any jeers (though I can see where others may have, from reading other posts) about how you were measuring, I was just saying I HAVE seen calipers that measure in 128ths (even digital) but *for me* I'd just as soon switch over to decimal by the time my precision needs exceeded 1/32" (Easier to calculate in my head a need to take away .0075" than wrap my brain around needing to take away 1/128")

Finally, as far as my late edit - I'd gotten a pop up that other replies had posted since I'd started typing , just as I was submitting , and evidently it had gotten to page 2 already (I was replying on Page 1, didn't realize there was already a page 2 to this thread...) Hence the follow up edit , Looking at date stamps (Just now, not this AM) all I can think is someone else posted a reply from page 1 as well, then found page 2 and deleted their post.... leaving a considerable time gap..

 

[Mike Selser]

Thanks. I found this in over a 12' length. Not sure if they make one that would fit my bandsaw. Is this a wood cutting blade, or a metal cutting blade? I actually do have a metal cutting blade, its a Lenox "Classic Bimetal", has 10/14tpi. I originally bought it to help me cut unruly materials like trustone or inlace acrylester blanks. Brittle, and they were tough to deal with when the blade had fewer than about 10 tpi. Currently, my bandsaw is set up quite well for this blade. IT does not waver, and all the guide bearings are about as tight as I can get them without unwanted contact with the blade. The distances are 1/16" or less for all guides. The feed rate with woods, though, has to be very slow with this blade, it does not cut fast or even at a moderate speed. The most I generally use it for with wood is to cross-cut pen blanks down to size. I used to buy these "bricks" of trustone, usually 1.5x1.5" or 2x2" around, 6-7" long, and I would rip them down to 3/4" around segments, or smaller pieces for segmenting. The blade works well with those hard, brittle materials. It actually works fine, generally, with wood...it does leave sawmarks, but, really, the only issue is the need to maintain a very slow feed rate. I guess, I'll just give this a try with some scrap wood, and see how accurate, and strait, I can get the cuts. Maybe this blade will work.

I get my blades from https://www.bandsawbladesdirect.com/lenox-diemaster-2-bi-metal-band-saw-blades. They make any size you want. The Diemaster 2 is for both metal and wood but I don’t cut metal on my bandsaw.

 

[Jon Rista]

That was sort of what I was aiming for originally - Was there some reason why you could not just sand/plane/whatever the INSERTS to fit the kerf being cut? As opposed to trying to cut a kerf to x width. Not a criticism in the least, just curious if there was some reason that the inserts could not be "shaved" down... which would save needing to get a precision cut kerf?

And lastly I wasn't making any jeers (though I can see where others may have, from reading other posts) about how you were measuring, I was just saying I HAVE seen calipers that measure in 128ths (even digital) but *for me* I'd just as soon switch over to decimal by the time my precision needs exceeded 1/32" (Easier to calculate in my head a need to take away .0075" than wrap my brain around needing to take away 1/128")

Finally, as far as my late edit - I'd gotten a pop up that other replies had posted since I'd started typing , just as I was submitting , and evidently it had gotten to page 2 already (I was replying on Page 1, didn't realize there was already a page 2 to this thread...) Hence the follow up edit , Looking at date stamps (Just now, not this AM) all I can think is someone else posted a reply from page 1 as well, then found page 2 and deleted their post.... leaving a considerable time gap..

Well, I didn't think measuring down to thousandths for a blade kerf was going to matter. I had it on fractions, kept it on fractions...that's all?

Anyway. I have a hand plane, however it needs to be sharpened better, and I'm not skilled with using it (bought an old one in mid december, have worked on sharpening the blade a couple of times here, but it is not cutting nicely...and I don't want to leave a bunch of digs in this wood trying to think it out. Further, I kind of wanted the 1/8" thickness for the items that will be using it. Originally I was even thinking of using some even thicker stuff, but even with a full kerf blade, at least originally, I was going to have the same problem: What is an easy way to adjust the offset of the blank to widen the kerf accurately. That's all I really wanted, a quick, accurate way to shift the blank for the second cut, without risking overshoot, and without having to shave off 100 tiny little shavings then check until I got everything right (which would mean, taking the blank off the sled, checking the insert fit, trying to realign the blank on the table, etc.)

I think with the hand planer, I probably don't have the right kind of stones, and my sharpening technique is very...novice. I have only two stones and a leather hone, vs. most of the skilled woodworkers out there such as Paul Sellers, usually work through three and then the hone. My hone is also brand new, and hasn't been worked in enough yet. In any case...blade cuts, heck, lot better than anything I've sharpened this far in my time as a woodworker (maybe a bit under 5 years now), but it doesn't shave well enough. I have very little skill with hand planing in general too, and this stock is already fairly thin (at least, for me, a real novice at this aspect of woodworking.) So, I know its possible to thin the stock...I just don't want to ruin it, and, I do like the thicker stock for the use case.

 

[Jon Rista]

I get my blades from https://www.bandsawbladesdirect.com/lenox-diemaster-2-bi-metal-band-saw-blades. They make any size you want. The Diemaster 2 is for both metal and wood but I don’t cut metal on my bandsaw.

Interesting. I was there earlier. I guess, when I choose my blade length (9' 8" or 116"), then the option to get a 3tpi blade disappears. I'll give em a call and see what they can do.

 

[Brian Gustin]

Well, I didn't think measuring down to thousandths for a blade kerf was going to matter. I had it on fractions, kept it on fractions...that's all?

Duly Noted. Curiosity sated.

Anyway. I have a hand plane, however it needs to be sharpened better, and I'm not skilled with using it (bought an old one in mid december, have worked on sharpening the blade a couple of times here, but it is not cutting nicely...and I don't want to leave a bunch of digs in this wood trying to think it out. Further, I kind of wanted the 1/8" thickness for the items that will be using it. Originally I was even thinking of using some even thicker stuff, but even with a full kerf blade, at least originally, I was going to have the same problem: What is an easy way to adjust the offset of the blank to widen the kerf accurately. That's all I really wanted, a quick, accurate way to shift the blank for the second cut, without risking overshoot, and without having to shave off 100 tiny little shavings then check until I got everything right (which would mean, taking the blank off the sled, checking the insert fit, trying to realign the blank on the table, etc.)

What about Sandpaper on a piece of MDF or Melamine (for flatness) A good quality sandpaper such as 3M's Cubitron (I'd probably suggest 150 or 120 grit) can remove .007" very (amazingly) quickly just hand rubbing it if you lay it out flat and then a bit of 2 sided tape on the veneer (for fingertip grippy-ness) and then just work it in circular motion , can very quickly take down a few thousandths at a time to fine-tune a fit, and maintain flatness of the veneer (I've been known to use similar method to fine-tune mitered corners on picture frames just to get a perfect 4 corners fitment) - no hand planing needed. Just wonder if you'd maybe considered that..? However I can see that having a jig set up to work with your specific blade and sled to make 2 cuts to get that perfect kerf could also be quite a bit quicker, especially if you are using veneers that have a very consistent factory thickness. (if they didn't have consistency then setting up a jig would be pointless, I'd think?)

I think with the hand planer, I probably don't have the right kind of stones, and my sharpening technique is very...novice. I have only two stones and a leather hone, vs. most of the skilled woodworkers out there such as Paul Sellers, usually work through three and then the hone. My hone is also brand new, and hasn't been worked in enough yet. In any case...blade cuts, heck, lot better than anything I've sharpened this far in my time as a woodworker (maybe a bit under 5 years now), but it doesn't shave well enough. I have very little skill with hand planing in general too, and this stock is already fairly thin (at least, for me, a real novice at this aspect of woodworking.) So, I know its possible to thin the stock...I just don't want to ruin it, and, I do like the thicker stock for the use case.

I suspect you may find with some experience that once you have your first blade sharpened properly (takes a lot of practice to do freehand honing- same as with turning - building muscle memory and all that) that you'll very often only need to go to your final grit and then stropping (Thus, only one stone needed, really) Only time I will drop down to coarser grits (with chisels too, as well as plane blades) is if I have a particularly troublesome spot or nick , after I got things sharpened up, OR if I am trying to restore an original bevel (because the secondary bevel has grown too wide) but that's rather beside the point, I suppose - as with most other things - practice makes perfect, but doesn't solve the immediate problem at hand.....

 

[Mike Selser]

Interesting. I was there earlier. I guess, when I choose my blade length (9' 8" or 116"), then the option to get a 3tpi blade disappears. I'll give em a call and see what they can do.

The .025 thick blade is not available in 3 tpi. The thicker .035 blade is available in 3 tpi or 4 tpi. Either should work ok.

 

[Doug Rasmussen]

Back in the day I had quite an extensive woodworking shop/business. Jon's problem would have been trivial to solve. Cut the slots with whatever blade makes consistent width kerfs. Then make insert's thickness to the kerf width less a few thousands for glue clearance. Problem solved. The inserts would been sanded to thickness on my Italian wide belt sander that was very accurate by woodworking standards. It makes no sense to me to try and cut slots to purchased insert thicknesses because those are very likely not to be consistent.

If you're into CNC and resin fillers you can do any variety of celtic knots.



BTW, I sold the woodworking business (which included production woodturning) not because it wasn't successful but because I owned the building and we got to the point of running out of space and zoning prevented expanding the building. So the decision was to switch to metal machining/engineering which has a much higher return on investment per square feet of shop space.

 

[Jon Rista]

Cut the slots with whatever blade makes consistent width kerfs. Then make insert's thickness to the kerf width less a few thousands for glue clearance. Problem solved.

This is what I've been pursuing.

As for the rest... If I had the equipment, sure, trivial. Lacking a CNC machine or any of the other tools a wealthy shop would have, I'm trying to make do with what I have, or can get very cheaply. If you have every tool you could hope for, sure, this problem would be trivial. Not everyone has every tool they could hope for, though...

 

[Doug Rasmussen]

This is what I've been pursuing.

As for the rest... If I had the equipment, sure, trivial. Lacking a CNC machine or any of the other tools a wealthy shop would have, I'm trying to make do with what I have, or can get very cheaply. If you have every tool you could hope for, sure, this problem would be trivial. Not everyone has every tool they could hope for, though...

It seemed to me you were trying to adjust kerf to fit the insert thickness rather than make the insert fit the kerf. Yes, I had quite a shop. But it wasn't always that way. I built a thickness sander very similar to the one Don W has listed in the for sale sub-forum right now. My sander cost almost nothing to build with scrap yard pieces and turned out to be a money maker for me. That homemade sander could make precision thickness inserts. Later I bought the Italian abrasive planer/sander. That business supported the family with less equipment investment than most serious hobby turners on this forum have.

As to having a CNC, we've gotten to the point that CNC's are not a sign of a wealthy shop. Nope, these days you can have a fairly good wood cutting CNC (or maybe two) for less than the price of a high end wood lathe. Then add in all the accessories, gouges, sharpening equipment, hollowing systems, etc, etc and you're in pretty deep for a hobby. A $5K CNC will do any turning type work I've seen on this forum. My CNC's only came after I moved from woodworking to metalworking. I did find wood "turnings" could be more profitably done on a metalworking CNC so that became a nice sideline from cutting metal.

 

[Jon Rista]

It seemed to me you were trying to adjust kerf to fit the insert thickness rather than make the insert fit the kerf. Yes, I had quite a shop. But it wasn't always that way. I built a thickness sander very similar to the one Don W has listed in the for sale sub-forum right now. My sander cost almost nothing to build with scrap yard pieces and turned out to be a money maker for me. That homemade sander could make precision thickness inserts. Later I bought the Italian abrasive planer/sander. That business supported the family with less equipment investment than most serious hobby turners on this forum have.

As to having a CNC, we've gotten to the point that CNC's are not a sign of a wealthy shop. Nope, these days you can have a fairly good wood cutting CNC (or maybe two) for less than the price of a high end wood lathe. Then add in all the accessories, gouges, sharpening equipment, hollowing systems, etc, etc and you're in pretty deep for a hobby. A $5K CNC will do any turning type work I've seen on this forum. My CNC's only came after I moved from woodworking to metalworking. I did find wood "turnings" could be more profitably done on a metalworking CNC so that became a nice sideline from cutting metal.

I don't want to reduce the insert by 1/32" though. I want it thicker. I could reduce it, but then I don't quite think I'd get the look I am after. Just because there is one way to do something, does not mean that is the only way to do something. Thinner loses the look. To be perfectly honest, I've been wondering if I could sandwich these 1/8" thick boards with a layer of 1/64" veneer on either side, to make these loops or rings in the finished product look even a bit more interesting. So long as I can figure out how much to shift the blank to cut exactly the kerf I need, I should be able to. That was really what I wanted out of this thread.

As for shop equipment. I don't have an income from this business yet. Anything I spend on the business just increases my losses right now. So I'm not in a position to spend money, even $500-600 for a very low end super entry level CNC machine, let alone another FIVE GRAND on a CNC that will "turn anything." Heck, spending $60 right now on a blade is not really what I want to be doing. How does the original concern I posted in my FIRST post about not wanting to spend $200 on a table saw blade, translate into spending $5000 on a CNC machine to you? I don't get it...

In any case. The trig I needed to figure out how much to shim my blank to cut ANY kerf I want with any blade, was already provided. So I can use a little bit of math, and create and add various shims to my stop to get a wider kerf of exactly the width I want. That's what I needed. I don't need recommendations to spend thousands of dollars to add machines to my already jam-packed full shop (that doesn't have an inch of spare room right now anyway) so I can do things "more easily." I'm a turner. All I've ever done is turn thus far. I'm trying to branch out into other things, WITHOUT spending thousands, or really even a dime, except on wood. I spent $500 on a low end table saw a bit over a year ago that I was originally using for construction. Now its a woodworking tool and I'd like to get some use out of it, before I spend more money on another machine. That was the goal. Being told by you that you had quite an extensive woodworking shop and business (which is actually where my quip about "wealthy" came from, not the CNC machine), and could do any of this easily, to be quite frank, is not helpful to me. Its bragging, childish, and quite frankly, a little annoying. I have no doubt that you are a vastly superior woodoworker than I am. I did not have that complicated of a question, which is why I'm surprised by the responses of a number of the forum members here, including you. For someone as superior in skill as yourself, you could use a change in tact.

Anyway, someone provided the real answer I was looking for already prior in the thread. That was quite helpful. Too me a sec to figure out I was accounting for my angles backwards, but now that I have, I can cut any kerf I want with any blade I want (well, so long as its thin enough, I guess, can't cut anything thinner than the blade kerf.) That's good enough for me. I can return this full kerf saw blade and save myself $60. Maybe I'll pull a profit this year, if I do, maybe next year I'll bring in enough that I could spend some money on another machine. Until then....I have wood, I'm just trying to figure out how to use what I have, spend as little as humanly possible, and see if it is even possible for me to try and make a business out of this or not.

I'll bow out of this thread now.

 

[Doug Rasmussen]

I did not have that complicated of a question, which is why I'm surprised by the responses of a number of the forum members here, including you.

I can't speak for other forum member's responses.

A number of years ago my first description of ovals was likely from where I learned most of what I came to know about woodworking. That was from the Delta series of books, "Getting the Most Out of Your xxxx". Each book covered a specific tool, table saw, lathe, drill press, shaper, sander and other shop tools. The table saw book shows how to do turnings on the table saw which can be a real eye opener. The oval process could be done solely on a table saw without need for a lathe by using clever jigs. The books are readily available through Amazon and other used book sellers. In our current litigious society no manufacturer would dare publish the information in those books about using tools in unusual ways.

I thought your question involved a lot of issues. The process you're wanting to do can be complicated. Complicated by the accuracy needed in the blank dimensions, having a saw blade that makes repeatedly accurate straight cuts, an accurate jig holding the blank for cutting, stopping off the center of your blank so the end doesn't have to be exactly square, etc. Then not cutting all the way through adds more complications if you have to get into shims to establish kerf width. If the cuts are all the way through the blank (like most Youtube videos show) the glue jig has to allow for precise clamping alignment where poor glue alignment can be a very major problem.