Category Archives: At Mark Grable’s Place

From Tree to Something to See

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Well, I’m heading home to Colorado for the summer by way of Brooklyn to visit Yann Guigere of Mokuchi Woodworking, which has given me some time to catch up on the last stuff I worked with Mark in Vermont.

The last bit of joinery I cut was a ramp for a deck, and it gave me the chance to use some of the Black Locust I sawed to boards at the beginning of my stay. The slope of the deck to the ground wasn’t enough to justify stairs, but the construction was similar, using wedged mortise and tenon and a sliding dovetail at the bottom of the stringers. I used a 6-3/4″ Makita planer to smooth and square the lumber prior to layout. God I need one of these machines! And I got to play around with a Hitachi hollow chisel beam mortise. The stringers I was mortising were too wide to seat the mortiser properly, so it ended up being faster to simply drill and chisel the mortises, but man, what a sweet machine.

This lumber made a bitch out of my disposable blade saws, by the way. I wouldn’t have been able to saw the tenons without some of Mark’s big ryoba nokogiri.

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The stringers for the ramp were live edged, with a beautiful curve that really fit the naturalistic round timber element of the deck railing. Everything cut, of course, to a center line.

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The locust was still very green, so I tried to cut the wedges extra long so they could be pounded in further as the wood dries, but also took the measure to back the joinery up with a few screws toed in on the inside in case someone failed to do so. I never seem to cut long enough wedges, in the future its a safer course to just make wedges several inches too long.

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It would have been nice to attach the ramp with sliding dovetails to the rim joist of the deck, but the decking was already down so it was attached with your conventional hanger and screws, landing on some local stone for a floating foundation. A heavy coat of Linseed oil/pine tar/turpentine finished things off and will help control the drying now that its in the sun, and Mark helped me chisel the corners to round and touch up a few details.

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We took a break at some point and went over to the neighbor who now owns the farm that was part of the property that Mark’s on, which has an enormous old timber frame dairy barn that is in places still sitting on a dry stone foundation. It had very workman like construction, no superfluous details, and it was great to see a timber structure hold up so well in wet Vermont.

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Back over at the house we finished up the railing.

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It was my intention when I first traveled to Vermont to help Mark cut the frame for his forge, but the universe is a funny place. And three months is only enough time to scratch the surface of saw making. I’m heading back to Colorado to take care of family and help my mother cut a small structure, keep her property development moving along as we permaculture the shit out of the place in the hope that it will help secure a sustainable future for friends and family. Being with Mark, a gentleman and a scholar, has changed how I approach my craft, in ways I am sure to still be contemplating for many months to come.

And, I left Mark with the beams of lumber for the forge frame stacked in the right order and ready for layout and joinery. My hope is to make it back out to Vermont in the near future and finish what we have started, and see this knowledge preserved for the next generation and beyond.

On another note, I’ve been drafting the fuigo plans based on Hirota’s fuigo, but have been unsure of the best way to present the material to people that want to make use of it. My free trial of Adobe that allowed me to make .pdf files has expired, so I would need to either publish a design thread with illustrations from sketchup, up simply make the Sketchup file available for download. I’d like to hear from people what would be the most useful format for a set of plans, please let me know.

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Brought to you by a happy woodworker.

Hirota’s Fuigo

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Interested in making a fuigo (Japanese box bellows) for your forge? Mark Grable has an old fuigo from a saw smith friend of Yataiki, Hirota. This is the fuigo that John Burt used to build a copy for Yataiki in Iowa, and its worth studying if you want to build your own because there are many technical refinements in shape and joinery that are very important to how the bellows is used, especially when it comes to pumping the bellows with your foot during yaki-ire.

I’ve made a fuigo myself, which you can find by searching the fuigo category on the left of the page. If you’re not too familiar with their construction your understanding of the following details will benefit greatly by reviewing and watching the John Burt video.

I’ve seen a lot of modern fuigo at this point, that while quite useful and functional, fail to meet the potential of what this tool is capable of as part of the total context of how a Japanese smith would work at the forge. The most common thing I see lacking is size, this fuigo measures nearly four feet long, with a total length of 116cm, and an internal displacement cross section of 25cm wide by 56 cm high.  Its made from top quality vertical grain Japanese cypress. The top and bottom are each a single board, and the long sides are made from two boards joined together.

Understand, fuigo are made in many different sizes, all the way from the monster bellows used in tatara production of tamahagane to the tinsmith’s tiny backpack bellows, but its worthy to note that Yataiki asked Burt to make a fuigo three inches wider than this one. By comparison, the fuigo that I made for my forge is about three quarter scale of this one, due primarily to the constraint of needing to store it out of the way on a shelf while not in use.

 

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The handle fits on a tapered round tenon, with the hole drilled in the handle at a slight angle so that it faces the smith more directly. In addition, there is the all important foot board on the piston shaft. This is what the toes of the smith’s foot rest against while pumping the bellows with the left foot, leaving both hands free to manage the coal bed and manipulate tongs.

Notice the groove that’s been worn in the handle by so much use? Respect.

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I originally thought that this board was simply held from slipping up the shaft by the taper of the tenon, but in this case it is evident that a nail was used to back the foot board up.

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Evidently a t-shaped cut nail by the looks of the damage to the bearing board, haha.

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In fact, the whole fuigo is assembled with nails, with some very interesting nails with an extra wide head used on the sides and birdhouse top.

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Another important detail is the curve to the sides. Its easy to say that the fuigo sides are curved both in length and height, but how much?

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Finally I can measure a working fuigo to get my answer, and it surprised me a bit. The long sides have a total deflection at the center of 5mm, and the total deflection of the height along the short sides is 2.5mm. Further more, the long sides taper in along their length 10mm! If the need for the curve to the sides can be ascribed to counterbalancing the internal pressure of the air bowing outward, perhaps the taper is due to the action of the foot pumping the bellows with a limited stroke with the piston rod almost all the way to the back of the fuigo.

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Looking at the bracing on the top I have often wondered why the front is boxed in, still not sure, but I do notice is that the battens are nailed only on the outside edge where the nails will come through outside of the dado’s that house the side panels. On the lower left there’s quite a depression that has been formed, perhaps by many years of a hand resting on the corner?

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Looking at the bottom of the fuigo top we can see the dados. I placed a straight edge against the outside edges and they have a bit of curve to them as well, not as much as the dado’s themselves, but just about what you would expect if you first planed the curve on the outside edges and used them as a reference for marking the grooves with a gauge, and then made the outside edges a bit straighter during finish planing.

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You can still see the saw kerf at the bottom of the groove from the azebiki nokogiri that was used to saw the dado lines. Haha, not too fine of a cut at the bottom, pretty much chiseled out quickly.

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One of the more subtle refinements is that the top edge of the sides as well as the dado’s in the top board that house them are tapered. After all, the top board is secured with only a pressure fit, but still needs to be removable and create a good seal against the internal pressure of the air when pumping the fuigo.

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And of course, the piston board is wrapped with raccoon fur, probably attached with rice glue.

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And the front stop for the piston head is about one third of the way down the fuigo. My guess on why the whole length of the box isn’t used has to do with the length of stroke that the human arm is capable of while seated, as well as the need to keep the piston board from jamming on the push stroke by keeping the bearing points separated by a bit of distance at all times. The piston rod bearing wasn’t a great fit, but that probably had more to due with the wear this fuigo has seen than any design consideration.

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A lot of the chamfers on this fuigo are shallower than 45 degrees. For example, the chamfers around the flapper valves that let the air into the bird house leave 5mm of side thickness untouched, when the total thickness of the long sides is 9mm.

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Although, the front and back flapper valve holes are not chamfered, not sure why. There is however gasket material sewn on to the front and back of the flapper.

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The dado’s on the top aside, the quality of the fits on this fuigo suggest that whoever made it knew what they were doing. Take, for instance, the fit of the bearing block to the curve of the long side, not a right angle. Similarly the edge birdhouse top is beautifully fitted to the curve of the long side panel, not a gap in sight, and consider that the long sides curve both in length and height.

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The joinery that connects the long side by the birdhouse to the short side is the trickiest bit, a half lap with concurring dado’s that slide together. There’s an extension on the long side that is quite weak, and I had one of mine snap off because of the tight fit of my joinery. It was beautiful to me to see that this had been taken into account by the craftsman by shaping the extension so that less wood rubbed against the short side panel (although there was still a crack here, haha).

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The last detail that I’ll discuss today is the air exit that connects to the carved kiri tuyere. Its tapered to fit the conical section of the kiri tuyere adapter, and also angles slightly towards the front of the fuigo. Why the angle? Perhaps it has to do with the length of the fuigo relative to the placement of the fire. The hole is also not centered on the length of the fuigo, lying slightly towards the front.

I hope this information is of use to those making fuigo for their forge. I took a complete set of measurements and drawings in metric which I’d like to draw up into a set of plans. Let me know if you have any questions, I’ll do my best to answer.

Sen and Sen-Dai for Hand Scraping Saws

 

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This is going to be a post with a lot of pictures, hopefully it won’t take forever to load on your web browser. To start, a method for measuring saw plate thickness, basically a red-neck deep throat dial micrometer using a drill press. By setting the zero on the dial to the thinnest parts of this saw I could write the deviation in thousandths directly on the plate, a grid of numbers. Supposedly this kind of saw plate variation of thickness for western panel saws is unusual, but it offers me a good opportunity to discuss the Japanese tools used to hand thickness nokogiri.

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With the grid of the saw mapped I built up a topographical map to better visually represent the variation in thickness. After all, if you’re going to scrape a saw evenly you need to know where to take off metal. This saw already went through quite a bit of hammer straightening, but the problems with the uneven thickness of the plate are making it difficult to get that last 10% of straight. The normal fashion for gauging proper thickness on Japanese saws is to bend the saw and observe the curve, and I can attest that this is, with appropriate experience a la Yataiki, an extrememly accurate way to thickness saws to within a thousandth of an inch, based on some of his saws that I have looked at with the dial micrometer.

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The tools used to scrape the saw plates are sen. You’ll find that these were once very common tools to all of the tool making blacksmith trades, including katana and kanna. Some of the sen pictured here are specialized for saw making, like the one at the very bottom of the frame, but there are others that could be used for hand scraping the ura (hollow) on the backs of Japanese chisels and kanna, or the flute on the sides of a katana.

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This particular set uses laminate construction with Swedish steel.

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And the final stage of scraping involves a lot of work hand burnishing the surface with a lot of pressure and elbow grease.

What kind of Swedish steel I would very much like to know, seeing as saying Swedish steel is about as useful as saying they are made from high carbon steel, there’s a lot of different kinds out there these days.

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Lets start with a frame of reference for what the hell I’m talking about. This is a photo of Yataiki thicknessing a saw at the sen-dai. Beautiful metal shavings, no? The sen-dai comprises both the board the saw is resting on and the staple vise used to hold the saw flat. The large staple goes over the sen board and is mounted into a foundation block of poured concrete in the ground, a large block about two feet wide by four feet long, very stable.

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For holding the saw down flat to be scraped on the sen-dai there are lots of little spring clamps and wedges. These are all used under the staple of the sen dai. The ball bearing is for rolling vigerously in hand to prevent blisters, the loop of steel is a way of binding the handles of a pair of tongs when forging. The little rectangular wedges hold the sen board against the wedge beneath it that gives it the proper downward angle for work.

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For holding the opposite side of the saw nearest where you would be seated are more spring clamps, elegant little pieces of spring steel that slip over the edge of the sen board.

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Saw makers don’t make one saw at a time, its more of a production affair. Here is a good stock of rough forged blanks, ready for rough grinding after the tangs are forge welded on.

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An elegant spring clamp in use.

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And under the staple the various wedges. The spring wedge holding the tang down has a curl at the other end used as a snell, for tapping the wedge loose.

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This is just a mock up of the sen-dai. There is one size of board for larger saws.

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And a smaller, thinner board for dozuki. Both of these are made from Kashi, Japanese white oak, the same wood used in plane dai.

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The staple spring clamp for dozuki have a variation with a little stop cut at the end that the blade butts up against.

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That allows for working right up to the end of the saw plate.

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In the past all of the thicknessing would have been done by hand. More modern methods involve a rough surface grinding to remove most of the excess material. Here is a ryoba saw, rough ground and tempered. Beautiful colour.

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Apparently dozuki are differentially tempered, softer along the tooth edge.

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What you’re seeing here is a dozuki blade that’s been hammer straightened after tempering with two different kinds of hammers. Fascinating surface!

 

Note: This post has been edited to correct an earlier mistake, referring to Japanese Oak as Keyaki (a type of Japanese Elm) instead of Kashi.

Cutting Compound Angle Mortise and Tenons

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Is modern digital technology running rampant in your life? Grab a saw! Join me for a little work and find out if your mind has been colonized by a corporation.

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I finished the stool yesterday, so time to work through the rest of the problems associated with making a splay legged stool. Its a good thing that I’ve waited to post about this until finishing, because I found a few mistakes I made that were very instructive in understanding this project, which I’ll go into more detail with on the final post of this series detailing the final assembly.

The compound angle of the mortises meant that chopping with a chisel would have presented some great difficulties, so I started by drilling the waste with a brad point twist drill. I used the layout lines on the sides and a straight edge placed on the side for visually aligning the drill.

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Just as you would for chopping with a chisel, drill half way through from both sides to reduce the chance of drilling waste outside the cut lines.

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The table mortises were first layed out on the bottom using measurements from the center lines of the board, with the lines transferring up on all four edges with the common 3.5/10 slope to the top. Because the mortises were too far in to sight accurately I used a bevel gauge placed at 45 degrees in plan to gauge the angle for the drill and its alignment. In this case the angle for the drill, because it is at 45 degrees to plan (top view) uses the displacement multiplied by the square root of two, working out to about 4.9/10 for the angle to set the bevel gauge to.  Why the square root of two? I’ll let you figure that one out, its very, very common in dealing with slopes that are a regular 45 degrees in plan.

To pare the surfaces of the mortises in the top I made a guide block for the chisel at the common slope, which applies to both the end grain and side walls of the mortise. One block to pare them all.

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I tried using the extra leg I had cut as a guide block for the mortises on the legs but found it faster to simply sight along the edge of the leg, and used a big timber framing chisel.

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Cutting the tenons was very special for me because it was the first chance that Mark has given me to try some of Yataiki’s saws. I used a 240mm ryoba for all of the cuts. This saw was very good, to put it mildly. My saws are all mushy disposable blade type, so coming from that to a saw like this is a quantum leap, and I joked with Mark whenever he asked how it was going that I had only broken off a couple of teeth. That is a real concern with lending someone a good saw to use, its no small matter, you don’t just hand a saw like this over lightly, and I greatly appreciated the gesture on Marks part to let me use this tool.

The saw was very thin, light, and finely set. Easy to use one handed, and really did all of the work without me pushing it through the cut. For the first time I felt like I was really experiencing new dynamics of the saw in the cut.

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Should you run across a saw with these Markings…

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Treasure it dearly.

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Yataiki gave this saw to Mark when he was teaching in Iowa for making charcoal for the forge and asking doing things like counting the number of teeth on a saw.

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It has some history, as the staining and hammer marks from hizumi will attest.

As an aside, I’ve been meaning to write a post on Marks hizumi hammers, but have been holding off because I don’t want to be too proscriptive about which hammer is the correct one for a particular task. What is important, besides the weight of the hammer matching the thickness of the plate, is the shape of the cross peen edge. And to that end, its easier to describe the correct shape and size of the mark it leaves than the degree of radius on its edges. Measuring the ghosts of the marks on this saw shows a cross peen mark about six millimeters long and one millimeter wide, an ellipse.

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The yoko-biki (cross-cut) are nice and slender little daggers, really well proportioned.

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The tate-biki are likewise pleasing to the eye.

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My normal method of ripping tenon cheeks is with the piece of wood held vertical in a bench vise, but I found the teeth of this saw too sharp and aggressive to handle the angle of cutting uphill to the grain. The alternative is cutting downhill with the piece held horizontally. The saw horse I’m working on is a bit low for this task but It worked nicely, with the advantage of being able to freely orient to the best light from the south facing windows.

Getting the chance to use this saw was a real eye opener for me. I knew my disposable blade saws weren’t that great, but the positive difference is almost unquantifiable, and I find myself hoping to buy, perhaps not a totally handmade professional grade saw, but something with decent steel that I won’t feel too bad about sharpening on my own. The world needs more saws like this!

Making a Saw Setting Spider

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Time for working with a new saw! This time its a 5-1/2′  two man cross-cut for felling and bucking, cuts on the push and the pull, with four cutter teeth to every raker. I’d been needing the use of a larger capacity saw for bucking logs prior to ripping with my whale noko, because my madonoko isn’t really meant for cuts over about half a meter. Now, I’ve made some pretty epic cuts larger than that with time and patience, but even after careful straightening by metate Mark my madonoko still wanted to wander on the opposing side of the cut, and it gets to be a real struggle to layout for boards on the end of the log when the surface of the end grain is concave.

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I’ve resisted the idea of two man saws for the simple reason that its damn hard to find another guy to get on the other side of the saw. If you do, damn, that’s a good friend, I tell you!

But a saw like the one in the picture above can be used by one person quite effectively as long as the cut is plumb.

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And! There’s some very interesting tools used in dressing these large saws accurately. The jig at the top of the picture above does three things. First, it can hold a file in a curved shape for jointing the tops of the saw teeth to the same level. Second is a pin gauge for setting the height of the raker teeth when peening over the hook. Lastly is another height gauge for finish filing the rakers to a consistent height, accurate to the thousandth of an inch. The tool at the bottom left is the setting spider, the subject of today’s post. How about some instructions?

Simmons Saw Sharpening Guide

And learn from the master filer I learned from, a fantastic set of videos that include a bit of hammer straightening of saws.

The spider is used as a gauge to accurately determine the degree of set in each tooth. Simple and brilliant, it immediately struck me that such a tool could be easily made and used on maebiki-oga.

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You’ll catch this if you watch through the videos above, but basically the spider has a small difference in height between the long arms. Placed on the saw you see how it rocks back and forth. If the long arms rock the tooth needs more set, if the short arms rock the tooth is over set. Its important to note that this tool only works if the plate of the saw is quite straight, flat, and even of thickness.

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I started by cutting a cross out of some mild steel a bit thicker than 1/8″.

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I stuck it in a vise to bend the edges over, filed a flat land on all the feet, and leveled them to the same height on my diamond stone.

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Then one leg could be lowered by grinding with part of the spider off the stone, checking how much material had been removed with a feeler gauge.  For the large cross cut saw the spider was set at about .012″, for my maebiki-oga I adjusted the spider to gauge .010″ of set, which with a plate thickness of .085″ gives me a kerf just under 1/8″.

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Luckily the plate on my saw is pretty consistent and flat, so I got right to work checking my set. Up to this point I’ve been setting by eye by sighting along the plate held flat. If you have an oga saw with a rough hammered surface you’ll have to depend upon setting by eye. I still don’t completely trust the spider, but it is a great analytical tool to gauge how well I’m setting, and weather I’m actually seeing the degree of set correctly. As it turns out, I had over set one side and under set the other, probably due to the change in orientation of the saw when flipping it to peen the teeth over.

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For setting teeth you need a small anvil, mild steel is okay, as long as it has a rounded edge that allows the tooth to make contact in the right spot. The teeth of a whale noko are hard enough that if you were to strike the tooth while unsupported you run the risk of breaking it.

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With the plate held in your lap at a lowered angle to the flat  you can place the tooth line on the anvil and strike the upper third of the tooth.

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I’m using a new hammer for setting, a cross peen with a ‘v’ shaped edge, not rounded, that is basically a large single edge version of a Japanese setting hammer. If you use too light of a hammer you find yourself whacking the tooth with a rather random amount of force. Adjusting the set within a thousandth of an inch requires control. Also, bending teeth back that have been over set on such hard steel is not an option, they just break off, so get it right or you’re stuck with an over set tooth until you sharpen it down a bit.

Happy sawing! I hope more people now are getting these big saws ready for the cut and avoiding the hassle of a chain-saw.