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DragonFly Harp #6: 1/12/2011

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Blog entry by Donna Menke posted 1290 days ago 3546 reads 0 times favorited 10 comments Add to Favorites Watch
« Part 5: Stand Mods- 1/6/2011 Part 6 of DragonFly Harp series Part 7: 1/20/2011 S-L-O-W Going »

Doesn’t seem like 6 days have passed, but the calendar does not lie. I have a lot to catch up with.
First order of the day was to edge join the pieces I would need to have wider- like for parts of the stand legs and the base of the harp.

These Bessey clamps are the best.

Then I needed to cut the angled sides. This was the most dreaded job, and the first rip (with the grain) on the table saw (my second least-favorite power tool). Took most of a morning to assemble the tool and then to figure out what angle needed to be cut. Finally double-sided taped the wood to the jig so that it would not slip during the cut.

Obviously the angle was not perfect, causing the wood to go through the blade at a slightly off angle- hence the burning on the cut edges. No worries, it will be gone with sanding later on.
I taped some 1/4” pieces of basswood to the backside of one of the edges to make the angled cut at 5 degrees on the opposite side. The blade only tilts one way. Last time I used the other side as a spacer- forgot about that this time. Should read my own blog! Would have been easier, and more accurate.
Then, the slots needed to be cut at 5 degrees, going the same direction on both edges, and the sides needed to be mirror images so that the soundboard and back would slide into them and be planar to the front and back sides. That took a lot of cogitation, but it came out OK, so it was worth the hours of set up.



Making the ends rabbets were easy once I got the angles right. I should have dug out and used the $150 SysteMatic dado set, but being lazy I just made repeated cuts with my $110 Forrest WoodWorker 2 blade. I will clean it up with a carving gouge. The dado set would have made a cleaner cut, but it would have take me an hour to set it up.

Now I get to do the fun part- using the band saw- my very favorite power tool. First I essentially designed the harp base on the wood. I had run it through the planer again to make it perfectly smooth on both sides. Here I’m using drafting tools to make nice-looking curves. Then there is the hard part of determining at what angle to make the cuts. Remember that the back and front are at two different angles- and, the side to side angles are different too.


Not one to trust the gauges on the machines- you never should- I set up with this bevel angle gauge. Then, just as a double check (because it is easier to over-check then it is to fix a mistake) I also check empirically, with the side itself.Now you know why it can take me so long to set up.

After making all the cuts I could get at with the band saws I got to do some hand sawing with my Bakuma Japanese back-saw. Love those saws. My Dozuki is my favorite saw and I should have used it here because it has finer teeth and would have made a better cut. Musta been getting tired.



I’m satisfied with the fit, especially considering the complexity of the cuts. I will have to do something to smooth out the design elements, but that will be for later, when I see it all together.
Now I will dry- assemble the base with screws and work on designing and making the top piece.
Additional time= 16 hours over 4 days. Total= 37, so far.

-- "So much wood. . .so little time!" www.woodworks-by-donna.com



10 comments so far

View Eric_S's profile

Eric_S

1521 posts in 1794 days


#1 posted 1289 days ago

Nice work Donna. You are making some good progress. I like the bevel idea for the bandsaw. I usually rely on the angle gauge. Maybe thats why my angled cuts on there aren’t accurate. I’ll have to try that tip, however I just bought a magnetic digital angle block so I’m going to test that out. When it comes to my piece of junk table saw though I NEVER rely on the stock angle gauge.

-- - Eric Indianapolis, IN

View Donna Menke's profile

Donna Menke

567 posts in 2864 days


#2 posted 1289 days ago

Ooooh- think that will have to be my next tool purchase- a magnetic digital angle block. When I clamped my pieces together in order to drill for the screws- lo and behold the tops of the sides met on the backside. . . that was not supposed to happen. After 2 hours of scratching my head I still don’t know how it happened, but I have a way to fix it anyhow.
First thing tomorrow I’m making some very accurate gauges using 3/4” birch ply- for 5, 8, 10, and 15 degrees. Heck I may even have to resort to some trigonometry to make sure they are accurate.
One more thing- I should have kept a log of what I was doing. I can hardly remember anymore which angles went where.
Talk about a puzzle!
It is all a good learning experience.

-- "So much wood. . .so little time!" www.woodworks-by-donna.com

View sras's profile

sras

3780 posts in 1728 days


#3 posted 1289 days ago

This is a very interesting story. I am looking forward to seeing this harp come together!

-- Steve - Impatience is Expensive

View Marty Backe's profile

Marty Backe

152 posts in 1370 days


#4 posted 1289 days ago

Nice post.

I don’t understand your explanation for the burning. I usually attribute burns to dull or improper saw blades. Are you using a high quality rip blade? I’m partial to the Freud blades. My go-to rip blade is their LM74R010 glue line blade. They’re not cheap, but with saw blades you get what you pay for, and they last a long time.

If you are using a quality rip blade, then the burning would be due to ripping at too slow of a rate and movement of the wood (away from the fence) during the cut.

Just some thoughts …

View Marty Backe's profile

Marty Backe

152 posts in 1370 days


#5 posted 1289 days ago

Oh, I forgot to take the bait – what’s your least favorite power tool? I’m going to guess that it’s the router.

View Donna Menke's profile

Donna Menke

567 posts in 2864 days


#6 posted 1289 days ago

It is a toss-up between the table saw and the router. It is funny though- anticipation is worse than actually using them. Once I get into it then my fear lessens dramatically and I’m OK- after making sure that I’ve done everything to make it a safe procedure.
Marty- I’m using a Forrest Woodworker II blade that cost $110 10 years ago- so that is pretty good quality. The burning was the result of having the taper jig not be perfectly aligned with the blade and so it went through at probably a 1/4 degree angle. Not enough to keep it from going through very close to the line, but enough to burn the always ready to burn cherry. I was also going too slowly I’m sure. Subsequent cuts have not burned.

-- "So much wood. . .so little time!" www.woodworks-by-donna.com

View Donna Menke's profile

Donna Menke

567 posts in 2864 days


#7 posted 1288 days ago

Thanks, Autumn, that is good to know. Would that be paint thinner? I will try it.
Spent 5 hours today checking machines and tools for accuracy. Then, scrapped my messed up tracings of the pieces and layout and started fresh- with greater accuracy. Even got hubby to dig out an old trigonometry book and use measurements to determine that the angle of the sides from base to top is 7 degrees- not 8. Changed when I widened the top but forgot to change the angle. Now I have the almost impossible task of changing the angles on the sides of the base- one degree. I will have to carve it since no power tool will be able to get in there. I think I can do it- I am, after all, a carver.

-- "So much wood. . .so little time!" www.woodworks-by-donna.com

View BarbS's profile

BarbS

2433 posts in 2684 days


#8 posted 1288 days ago

Wow Donna, very ambitious! Interesting blog.

-- http://barbsid.blogspot.com/

View Marty Backe's profile

Marty Backe

152 posts in 1370 days


#9 posted 1287 days ago

Now I do understand your description of the burn cause. Looks like you have a good handle on it. A nice blade for sure. 10 years? Remember, they don’t last forever – a great new blade eventually starts cutting like a cheapy (not that yours is – just a general comment). Even after having them sharpened, they never seem to be as good as when new, from my experience.

I hate burn marks. I don’t envy you the upcoming work to clean up those.

View Donna Menke's profile

Donna Menke

567 posts in 2864 days


#10 posted 1287 days ago

Marty- at the rate I use my table saw blade it may just last for my lifetime. Give ya a hint- it had not been used since I made the last harp- in 2007! No kidding. I’m OK using it now, but the first few cuts are always full of anxiety- unreasoned fear- extra caution- memory of a bad kickback in 1973 (I have a long memory and don’t forgive easily-LOL). And when hubby needs to use it to cut construction-type lumber I change the blade.
Now- band saw blades are another story. I go through them because I use them. Funny thing has happened- the 1/2’ Wood Slicer blade I had on the Jet 14” has become dull. It was working great before I cut all that foam. Is it possible that the soft-like-it-isn’t-even-there foam could have dulled my blade. It is about 3 years old and has been used a lot, but not abused. I tried to resaw 5 1/2” cherry and ruined the board- twice. Cut way crooked (even with a resaw fence) and tear-out on the bottom is ridiculous. Guess I need to put in one of the brand-new 1/2 or 3/4” Timberwolf blades I have in stock and try again.
I have been planning to round-over (sanding) the edges that are burned, so the burn will sand away then. The dimensions there are not at all critical.

-- "So much wood. . .so little time!" www.woodworks-by-donna.com

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