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Resaw Sled Prototype
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10101&t=15246
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Author:  Kent Chasson [ Thu Jan 03, 2008 6:49 pm ]
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After some recommendations from some folks here, I got my old Laguna 16 (Meber) set up with the new ceramic guides. This Meber model saw leaves a lot to be desired but it's working.


My goal was to get this dialed in well enough that I could get 3 back sets (6 pieces) out of 4/4 lumber. One of the problems I've run into in the past was wandering cuts due largely to the ripped piece cupping against the fence and putting sideways strain on the blade. I devised this sled to try to get rid of that problem and so far, so good.


It's basically an X-Y axis table. The axis perpendicular to the blade moves the stock over after each cut while keeping the sled parallel to the blade (adjusted for drift). The sled rides on the parallel axis. The finished version will hold the stock with vacuum, double sided tape for now.


The advantages are that there is no fence for boards to cup against and that the weight seems to reduce vibration while making steady feeding much easier.


My question for those of you who have done a lot of resawwing is, how much waste can you reasonably expect from the kerf AND sanding? I did some cuts in 8" hard maple and the Timberwolf ASS blade I was using took less than .050" and the cut was so clean that I only had to sand about .007" per side to get it totally clean. A total loss a little more than .060". Does it get much better than that? I've only got about 4 hours into this thing so far but tightening it up will be a time sink.


Some photos...




Author:  MaxBishop [ Thu Jan 03, 2008 11:45 pm ]
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Hey Kent,

That looks like a cool setup! I have had issues trying to cut uniform thickness bindings and this type of jig looks like it could really help. Thanks for sharing.

Max Bishop
Brighton, Michigan

Author:  erikbojerik [ Fri Jan 04, 2008 1:05 am ]
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Cool sled!



0.060" waste per cut?  So 5 cuts leaves you with 6 slices that
each finish (both sides sanded?) at a little over 0.1" per slice? 
Sounds pretty good to me...30% waste factor. 



Best I've done is a little under 40% waste from 4/4 with a new
Woodslicer blade, but I haven't all that much experience, maybe 30
B&S sets and as many drop tops for electrics.



FWIW most of the cupping issues I've had tend to come when cutting
flatsawn stock especially with a blade that is beginning to dull; seems
like the piece tends to heat up in the cut and the top & bottom
edges start to cup with the grain and drift away from the fence. 
So a vacuum-clamp resaw fence sounds like a wonderful thing to me.



Author:  AndrewGribble [ Fri Jan 04, 2008 1:36 am ]
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Kent, if you are getting 3 back sets (6 pieces) from 4/4 lumber (1" to 1-1/8" thick) how thick (or thin) are your pieces?

Author:  Brad Way [ Fri Jan 04, 2008 2:27 am ]
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Kent...nice setup. I have thought about making something simlar but was never sure if it was worth the effort. Up until now I have been using a "point" fence has some advantages and some disadvantages. I will be curious to see what others have to say about resaw setups.

Author:  Kent Chasson [ Fri Jan 04, 2008 3:38 am ]
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Thanks, glad it's helpful.


Andrew, theoretically, I should be able to get finished thicknesses close to .110". That's 6 x .110" = .660" plus 5 times the .050" kerf/sanding waste (.300") for a total of .960". Throw in another .020" for slop and .020" for flattening the original board. That's optimistic and all in theory though. Haven't tried it on good wood yet!


I'm not sure I can get those results in something like cocobolo though. I'll post again when I do some real wood. But one great benefit was that I got rid of ALL the saw marks in 4 passes per side on my drum sander with worn out 180 grit! The savings in sanding alone could be worth the trouble.


Another thing, the Timberwolf ASS gives a great cut but, as it says in the Griz catalog, use these "where speed is not a concern"! They mean it. Took me about 2.5 minutes to cut a 18" piece of 8" maple. I have a Resaw King blade too but have yet to try it.


Author:  Bob Garrish [ Fri Jan 04, 2008 9:14 am ]
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The cut on the resaw king is amazing, as well, but it's once again super slow compared to the aluminum master type blades. I keep the RK around for sawing Brazilian, but most everything else gets the aluminum blade.

Gotta get around to making a vacuum sled one of these days, just for the convenience of it if nothing else. I can get great yield already but the physical technique of doing it is quite tiring compared with only having to control the feed rate.

Author:  Kent Chasson [ Fri Jan 04, 2008 4:25 pm ]
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Filippo, I'm a resaw amateur compared to some of the folks here but here's what I know...


-The saw needs to have enough power and be well tuned. Google, of course, will get you tons on that.


-Limit vibration by making sure the wheels are true, the tires and belt are in good shape.


-Good guides, well adjusted (these laguna ceramic ones are great!).


-The right blade (lots in the archives here on that).


-Steady feed is huge. Stalling or changing speeds can cause some serious blips. The sled is great for that as would be a power feed.


-Proper blade tension. I've heard one theory that most people over tighten and looser blades gives better results. From my experience, I don't buy it. Blades may last longer but cuts can wander.


-Excellent dust collection. Good for the lungs and quality of the cut.


Author:  Barry Daniels [ Sun Jan 06, 2008 4:43 am ]
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Kent, I have been thinking of upgrading my 16" Laguna from the
original European guides to the ceramics. Did yours have the
European style guides? Do you think its money well spent?

Author:  Kent Chasson [ Sun Jan 06, 2008 7:20 am ]
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Barry, my saw had Carter's on top and the European guides below. Those particular Carter's were ridiculously hard to adjust. The European were OK. Either way though, the ceramic guides are better. They reduced blade vibration very noticeably.


I figure they will pay for themselves if they allow me to get a few extra sets of resaw yield, and I think they will in a short time.


I'm a little concerned they they are brittle and could be broken by a mishap like a bad weld or a blade that gets kinked without breaking. Haven't heard any reports of that though.


Author:  Bob Garrish [ Sun Jan 06, 2008 11:53 am ]
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They are brittle, and they will chip if a blade smacks them for whatever reason. You can get replacement ceramic chunks from Laguna, and you can just flip 'em around if the front edge chips. But they're still worth it.

Author:  Kent Chasson [ Sun Jan 06, 2008 12:55 pm ]
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Bob, is it worth having some extra pieces on hand or can you usually keep working one way or another until replacements arrive?


As for reversing them, how? I haven't looked into it at all yet. Are they glued? Release with heat? Friction fit? (I know I can find out from Laguna but since you've done it....)


Thanks.


Author:  Bob Garrish [ Mon Jan 07, 2008 9:36 am ]
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I think they're glued in, though maybe they just got stuck from being in there for so long. They'll come out with a torch either way.

You shouldn't damage your guides so often that you'd need extras on hand. I still have my original set, chips and all, and they still work fine.

Author:  Bruce Dickey [ Mon Jan 07, 2008 10:06 am ]
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Kent, how do you compensate for blade drift with an xy axis sled?

Blade drift is the natural angle one must maintain depending on the blade being used. Two identical blades will have different blade drift.

I've seen blade drift as much as 1/2 inch across the table width.

Just wondering. It's the first thing I do when installing a new blade, determine the drift angle and set the fence accordingly.

Nice looking sled.

Author:  Kent Chasson [ Mon Jan 07, 2008 11:32 am ]
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Thanks Bob.


Bruce, The sled just sits on the table and clamps from underneath. It doesn't lock into the miter slot or anything. So I just draw a line parallel to the edge of a scrap board, saw on the line for awhile, stop the saw without moving the board, mark the edge of the board on the table, and clamp my sled parallel to that line.


I just got the vacuum hooked up to it and am sawing some mahogany to get the rest of the bugs worked out. If all goes well, I'll post some more pics tomorrow and have a better idea of how accurate it is.


Author:  Kent Chasson [ Thu Jan 17, 2008 6:04 pm ]
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Thought I would follow up on this now that I have done more than a few test pieces.


I was overly optimistic about yield (why is it that test runs never actually work out like the real thing?)


I added the vacuum set-up. By the way, if anyone doubts the holding power of vacuum, I suggest you get one finger pad on each hand stuck between the board and the platen. Nothing to do but loose some skin, say a few choice words, and never doubt again how much vacuum can suck.


I also added the eye bolt adjustable stop which works great.


To make a long story short, given that every other species I tried after my test maple pieces required more sanding to get out the saw marks, the best I was able to do was get (6) .085" sides out of a .900" thick piece of Wenge with a Timberwolf AS-S blade. Kerf was .055" and the pieces needed about .010" sanded off each face to get out the saw marks.


The sled would benefit by adding some linear rails for the horz axis. The long axis is easy to get play-free but the short axis would not stay perfectly parallel on it's own. The point fence took care of it but then you have the issue of a cut that degrades just a bit with each pass as the point fence rides over the saw marks. A short axis that is spot on and lockable would be a good improvement.


The big disappointment was the Laguna Resaw King blades. They literally would not even cut 4-1/2" cocobolo sides. It would lock up like a kick back and made a terrible mess. In Wenge, they wandered terribly. The cut went from .130" to about .250" and back again. Maybe these particular blades were defective. And Laguna did say they will re-sharpen or send me some new ones but it was strange. The Timberwolf (at 1/8 the price) cut fine. I could only cut mahogany with the Resaw King and it even wandered a bit there. Too bad because the kerf is thinner and the finish can be way smother than the timberwolf.


The timberwolf did start to have some problems in coco after cutting several sides though. The oily dust wasn't clearing well and started building up on the blade. Any recommendations for dealing with coco? Forget the thin kerf blades and deal with the waste?



Author:  Marc [ Fri Jan 18, 2008 4:26 am ]
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[QUOTE=Kent Chasson] ...The big disappointment was the Laguna Resaw King blades. They literally would not even cut 4-1/2" cocobolo sides. It would lock up like a kick back and made a terrible mess. In Wenge, they wandered terribly. The cut went from .130" to about .250" and back again. Maybe these particular blades were defective. And Laguna did say they will re-sharpen or send me some new ones but it was strange. ...[/QUOTE]

I have had a lot of trouble with the Resaw King. The first one I had would wander, cup, barrel, no matter how much careful drift-tune-up or how tight the blade. It also left burn streaks. Ultimately cost me a back and side set of honduran rosewood. Laguna sent me a new one, it had some surface rust on it but they explained that happens since they are by the ocean. It didn't work any better. I really don't use it for anything now.

In my opinion the Resaw King doesn't have enough set in it, it tends to drift sideways along a path of least resistance, especially on a 7 inch plus resaw. I now use the laguna 1.3 tpi extra thin for resaw, they are cheap ($.20 per inch compared to $1.60 for R.K.) and resaw super straight and quick. There is a lot of deep scratches to be removed but that is far less of a loss than a cupped board.

BTW, if you are getting strange kicks using the R.K. you might check to make sure you have your back ceramic guide positioned firmly against the back of the blade. If it is off even a little, sometimes the pressure of a resaw will push the blade far enough into the guides that the edge of a carbide tooth will catch some of the side ceramic guide causing a bad kick.

Author:  Bruce Dickey [ Fri Jan 18, 2008 4:48 am ]
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Marc and Kent,
The best blade I've used yet is the Lenox TriMaster. When those first came out they were flawed, had a band that would not flex, but when they changed that, it's a killer blade. Very expensive too.

They have another blade which I have enroute called the Lenox Woodmaster CT 1", .o35" band, .o51 kerf, 1.3 TPI, so it is a less expensive blade, but likely wont' wear as well as a 2/3 Varitooth TriMaster. This blade is about 105 bucks, the trimaster is close to 175 bucks.

I also am trying some new blades Lenox Woodmaster C 1" for 18.12 each, .035" band, mainly I'll use this for cutting tops.

Then they have an intermediate priced blade I am trying the Woodmaster B1 a bimetal .o35 2 tpi, it should be good in light hardwood such as walnut it's 48 bucks.

I've tried some other brands of carbide, one problem one was returned. They checked it with a microscope, turns out, one third of an entire band roll had not been properly sharpened. So an out of the box test on these expensive bands is critical to getting a good blade on your saw.

Great thread. Resawing ain't for wimps, it's real work!

Author:  Bruce Dickey [ Fri Jan 18, 2008 5:00 am ]
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PS Rick Turner is really happy with the ASS Timberwolf blades. I remember those as quite reasonable too.

PSS Bob Garrish mentions the resaw King from Laguna as smooth cutting. So we can have different experiences. I've not tried those. I see he also uses the Aluminummaster from Lenox. When I heard of that I was going, aluminum wow, that couldn't be strong at all and would break.

Turns out the aluminummaster is very much like the trimaster, only for cutting aluminum. Many of the carbide blades are really not for woodworking, but work well anyway.

I'll never forget when someone told me they cut aluminum stock on their 14 inch delta standard wood cutting band, I thought they were crazy. I've since enjoyed jigmaking using aluminum and all cut on my cheapo Olson steel 1/4 inch band on my 14 Delta. Love it immensely. Aluminum is great for jigging. You can even thread it.....

Life is good. TGIF everyone!

Author:  Kent Chasson [ Fri Jan 18, 2008 5:46 am ]
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Marc, yes, the thrust bearing was the first thing I checked. The guides were close to the gullet but not into it. I went over everything several times, even tried a second blade. Cranked the tension, loosened the tension. My best guess is that chips weren't clearing but I really can't say.


And speed didn't matter. One cut took me over 3 minutes to get through a Wenge back and it wandered so much that I only got one set out of a 1" board.


Resawing ain't for wimps, it's real work!


Indeed. Not only am I missing some chunks of skin from getting pinched by the vacuum, there are the nicks from blade changing and adjusting and the blisters from pushing against the sled for hours. And that's nothing compared to the bruises from beating my head against the wall!


It's not just about saving money for me though. I just think it's a shame to waste 50% of such a limited and precious resource before we ever even cut it to shape!! Gotta be a better way.


 


Author:  WaddyThomson [ Fri Jan 18, 2008 5:59 am ]
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This is a little off the subject, but has anyone figured out how to uncoil a blade without ending up with your forearms bleeding, from the teeth whapping into them?  Even small blades are a problem for me.  There must be a secret that I haven't learned yet.  Big ones must be near impossible to deal with.

Author:  JohnAbercrombie [ Fri Jan 18, 2008 6:27 am ]
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Waddy-
I haven't figured it out either...I usually take the coiled blade into the back yard and gently toss it on a nice soft patch of lawn (while wearing leather gloves and a shop coat).
So I'm 'all ears' on this one.

Cheers

John

Author:  Marc [ Fri Jan 18, 2008 6:41 am ]
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Waddy,

Not sure it's possible without a suit of armor.

When changing blades I wear a long sleeve shirt, leather apron, heavy leather gloves, eye protection. I still get nicked through the shirt.

The 1.3 tpi, 1 inch wide blade is particularly hostile, it'll spring out of its coil with force and get you with its long teeth.




Author:  Bob Garrish [ Fri Jan 18, 2008 7:30 am ]
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Figure out where the blade's going before you pull it apart. Once you know where it's going, you can be ready for it and your chance of injury is lessened considerably. I've never hurt myself on a blade, and I don't even wear gloves (coiling or uncoiling) most of the time. Mind you, the no gloves thing is -not- a step in the right direction if you're having problems

With any blade, I think the setup of your guides is absolutely essential. I spend the better part of an hour setting up the saw for each resaw session. It's Murphy's law with blades. The resaw king has a thin band and so if you let it deflect it will, unlike something akin to the aluminum master which is a good deal beefier in the band and has a higher tolerance for issues with setup.

On the resaw king kick I have a couple new theories. One is that the drift on the saw might be off (so it would kick once the board was pushing sideways on it too much due to drift). The other one is that it's not clearing and it's causing it to bind in the cut (or insufficient motor?) and the bump is the blade momentarily buckling and then being pulled through the cut. Hard to say from here, but they seem like plausible causes for that behavior.

Author:  Bruce Dickey [ Fri Jan 18, 2008 7:51 am ]
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Coiling and recoiling.

Check out Highland woodworking site, they have it all in the library.

I finally printed it out with drawings and taped it up on the backside of my Laguna.

I do remember it's important to use your foot, and gloved hands. And you have to stand up with it as you uncoil a blade, reverse is true, squat down with it as you coil it up. Where you start with your hands is all important.

I've also done the "let 'er fly" method and it works well for uncoiling, teeth up, of course.....

With the best blades, and the cantankerous woods we cut, I've found to count on 1/4 inch per slice, less the saw kerf, well, you come out with useable slices, usually an extra too, which can be used, just not too saleable, those orphans. Still, I'd rather have an orphan a billet, than ten pieces that won't clear in the sander.

All the wood I've gotten from LMI or Allied has been 3/16 or better and usually with resaw marks. They know. I've noticed that tops however will often have one side sanded..... why....?    (grading),,, ahhhh!!

We're having some fun now. If your new blade isn't performing it may be it's just no good out of the box. Try another.

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