Wednesday, December 4, 2013

Home-made Hollowing Tool

We're putting up a Christmas Tree for the first time in nearly a decade, and I thought it would be fun to make a couple of turned ornaments on the lathe.  I like the ones that are a globe with a finial beneath and a hanger button at the top made out of contrasting wood.  So I made a practice globe out of a piece of cherry firewood, and realized I really needed to hollow it out to prevent it from cracking, and also to reduce the weight so it would hang on the tree nicely.

I drilled a 1/2" hole down the center and used a small spindle gouge to remove as much material as I could reach.  It kind of worked.  I couldn't get to a lot of material just inside the opening with the end of the straight tool.  So I picked up a 5/16" steel rod stock and some brazing rods at the orange borg a couple of days ago, and made a hollowing tool for under $10.

I bent the last few inches of the rod about 20 degrees in a vise.  Then I got an old 3/16" drill bit ("black oxide" no mention of the alloy used) and ground a flat on both the steel rod and the drill bit so they would mate together.  I wrapped a bit of thin steel wire around the assembly to hold it while I brazed them together, which I did with a common propane torch.  I've never brazed before, but it's pretty much the same as soldering, which I've done plenty of.  I didn't use any flux paste, just the stuff that was on the outside of the rod.

I cut the drill bit off about 1/2" long, shaped the tip into a scraper, and did some general cleanup on the grinder.  Then I turned a quick handle out of a scrap of alder and a 1/2" copper plumbing coupler, and epoxied it all together.  I gave it a very quick test-drive, and it seems to work well enough for my purposes.
Quick-n-dirty Home Made Hollower

Failed Braze Joint

Update:  I put it to the test tonight, and it started working well, but the braze failed and the cutting tip fell off after a few minutes.  I can see that the brazing alloy only stuck to a very small part of the joint, which I think is due to the tiny amount of flux used.  Basically, whatever melted off the rod when I was heating the joint is all there was.  I'll get a can of paste flux and try again.
Brazing is pretty easy (2nd time around)

Update 2:  I picked up a can of Harris Stay-Silv flux at a local welding shop and tried again.  That braze seems to be much more thorough.  I successfully hollowed out the previously unreachable spots on a little globe, although my cutter could use a little tuning on the grinder.  I'm a little torn on this brazed construction method, because I could also buy some carbide tips, drill and tap the end of the rod, and have interchangeable cutters that last forever anyway.  I could also drill a 3/16" hole in the end of the rod, insert my cutter, and fix it in by brazing or with a little set screw.
Hollowed Globe for a Christmas Tree Ornament, ~2" dia.

Monday, October 28, 2013

Filling Surface Defects With 5-minute Epoxy

I'm working on a tabletop right now.  It's Bigleaf Maple, and it's got a few surface defects like small cracks in knots, and beetle tunnels.  These are part of the natural beauty of the material, but on a dining table, little holes will just fill with gunk.

So I filled them with clear 5-minute epoxy, which was really easy and preserves the look.  The finish on this top is simple: a couple of coats of Watco Natural to pop the figure and bring out depth, followed by a topcoat of oil-based polyurethane varnish for durability.  I was concerned that the epoxy might fill the pores around the defects and change the way the finish looked, so I tested doing the Watco first, then the epoxy, then re-applying the Watco where I scraped and sanded around the repair.  I also tested simply putting the epoxy on the raw wood before even doing my final surface prep.

The latter is much easier, and worked fine for me.  At least with these finishes, and, more importantly, on this smooth, closed grain wood, the epoxy is too thick to really soak in and cause problems.  If I were working in oak or something similar with a lot of big pores, I'd probably do a prefinish step.  This process also becomes much more difficult if you're going to stain and want the defects to blend in.  In that case, you can try coloring the epoxy with a small amount of dye or paint pigment (go darker than you think) or try pre-staining and filling over it.

Here's what I did.  I got a tube of 5-minute epoxy at the hardware store.  Common stuff.  Squirt out a bit into a plastic cup or onto a piece of scrap, and mix it slowly but thoroughly.  Try not to get many air bubbles, because they'll show up in the filled hole.  You can see a few in the second photo after I scraped it down.  Dab the epoxy into the voids, working it down with a toothpick or similar so it makes good contact with the inside surfaces, and leave it very proud of the surface everywhere.  You don't want to have to try to come back and fill a little shallow depression because you didn't use enough.  Work quick.  If you mix it right, it will start getting thick and stringy in...  (spoiler alert!) about five minutes.
Overfill the holes.  It's easy to scrape off later.
Let it cure for at least a few hours.  It shouldn't feel sticky or leave any dent when you press on it.  Now it's time to shave it down to the surface.  I usually start with a sharp block plane, but you can use a chisel if you're careful.  Just shave off thin slices.  Don't try to remove the whole bump at once, or you might just pop the entire patch out of the hole, especially if you applied an oily finish first.  Once you get it down pretty close, get the card scraper out and continue gently shaving until you've removed all the excess and are just biting into the wood all around the patch.  You can also try a stiff sanding block, but a flat scraper does a much better job because the epoxy is inevitably tougher than the wood and you run the risk of sanding a divot around the patch trying to get the last bits of epoxy off.

A flat card scraper is the best tool to make the patch perfectly flush.
Then I do my final surface prep.  In this case, I used a random-orbit disc sander and some 150 grit paper over the entire top before applying the Watco.

Saturday, September 21, 2013

The Anarchist's Litterbox

With apologies to Chris Schwarz.  Or maybe not.  Do anarchists apologize?
The Anarchist's Litterbox

It's just a plywood box with poplar bracket feet and trim, built in a similar style to his "Anarchist's Tool Chest" except with a 8" x 10" feline access portal in one end.  With the exception of the plywood panels, everything was cut, shaped, and joined by hand, which was a lot of fun.  I didn't dovetail the trim because this chest won't get much physical abuse, and I didn't want any more chances to screw up, but I did glue up an acrylic tray for the bottom, to fend off the inevitable splatter of cat wizz.

Inside view - it holds all the feline sanitary accoutrements,
including a minimal but sufficient tool set and a box of fresh
litter below the sliding tray
The hinges are crap from the borg, stripped of the ugly zinc plating by an overnight bath in white vinegar.  There's a sliding till in the top, made of reclaimed old-growth Douglas Fir, dovetailed by hand (badly) and riding on waxed rails of quartersawn white oak.  I carefully considered each tool stored in this till, and for a few bucks I'll send you a DVD with a video where I go through them.  Ha ha.
Look at those authentic iron stains
from olde timey construction methods

The inside is finished with shellac, because I hear it's a good barrier to objectionable odors.  The outside is interior latex house paint.

Friday, August 9, 2013

The Overly-Complicated Through Tenon

I'm helping my friend Lori with her maple dining table project.  It's a trestle design, with a single stretcher, through-tenoned into the trestle legs.  It's intended to be a knock-down design with tusk wedges holding the tenons.  The stock was only 4/4, so the finished stretcher is only about 7/8" thick, which means the mortise and tusk would only be a little over 1/4" thick if the joinery is done vertically.  That would probably work ok with a tough wood, but I feel like there's a small risk of racking forces splitting the leg with that narrow pressure point, and the proportions just aren't right in the context of the piece.  The easy solution is to put the tusk tenon through sideways, but then it's just pinned and you lose the beautiful gravity-assisted wedge action that keeps the joint tight as the wood moves with the seasons.

So I came up with this.  It's got a cross piece horizontally through the end of the through tenon.  That cross piece is relieved in the back so that wedges can be put in to pull the joint tight.  I did a quick prototype last night and Lori likes it.  I think the madrone cross bar with walnut wedges looks nice.  If it turns out ugly or fiddly, I can always just cut a single horizontal pin and do it that way.

Through Tenon, Pinned and Wedged - this is just a mockup using some blocks
Update:  This turned out great.  The maple and madrone came out remarkably close in tone after a coat of Watco "natural" so I lost the coloring, but the physical aspects of the joint are solid.  I did the joint the same way for the bench that goes with the table.  The only trick I have to share is in fitting the wedges.  I cut them really long (~16") with a tapering jig at the table saw.  Then I tapped them into place, with all the rest of the parts cut, and marked where to cut them to length.  That way I don't have to worry if one side is a bit tighter than the other.

Monday, February 25, 2013

Using a Concrete Edger

I poured another set of curbs for a new fence I'm building along the east side of our property.  Using an edger to put rounded corners on a concrete job is the easiest thing to make it look professional.  The key is to wait until the proper time to use it.  Too soon and the shape doesn't hold, too late and it's very difficult to work.

Basically, I fill the forms, level them off and then float them with a metal trowel, then go away for a while.  The amount of time depends on the temperature.  It was about 45˚F when I did this job, so I waited about 50 minutes and it was still plenty soft and workable.  In the summer, it might be less.  Usually about 15 minutes after you pour and screed and whatever you do initially, there's some water that bleeds up out of the concrete.  Don't touch anything while this is present.  Wait until it soaks back in, then give it a few more minutes.  If you start the process and the surface is still really soft, you can always come back later.  You want the consistency to be a little softer than modeling clay.

Start by digging in with the trailing corner to define the edge of the concrete

I use an edger in two steps.  First, I hold it up at an angle and drag it against the form to define the outer edge of the curb and create a track for the tool to follow in the next step.  Then I lay it down and use it to float and shape the surface.  Just apply light pressure and slightly lift the leading edge of the tool.  It's really pretty easy.  If the concrete is still pretty fresh, you can float up a lot of water and make the surface soupy.  Stop and come back in a few minutes if this happens.  Just work it until the shape is defined - and stop, or the cured surface will wind up weak and crumbly.  If you want to float it really smooth, come back when it's firmed up a bit more and give it a final pass.
Then lay the edger down to form and float the surface

Wednesday, February 13, 2013

New Turning Tools from Glen-Drake Toolworks

Lie-Nielsen's Hand Tool Event came to town last weekend.  It's a great place to play with all their offerings, and ask questions about maintaining and using them.  I got some solid advice on sharpening small blades, and bought one of their small bronze spokeshaves.  What a sweet little tool, especially compared to the crappy Kunz (Stanley knockoff) I have at home.  I also made several cuts with their thin-plate dovetail saw, and now lust for it even though I have a perfectly functional Veritas model.  It cuts like a shark with lasers attached.

Anyway, there are typically also other vendors there, and Glen-Drake was one of them.  Kevin Drake was demonstrating some new spindle turning tools he's developed, and I'm definitely intrigued.  There are six of them, two sizes each of three types:  a rectangular-shaft skew, and round-shaft skew, and a round-shafted chisel ground with a bevel on top and bottom, like a non-skewed skew...  He calls it a duckbill.  That's it.  No gouges.

Kevin Drake demonstrates his turning tools

The tools are short, only about 14" long, more than half of which is handle.  The business ends are stout, and made of O1 steel instead of HSS that's the standard for turning tools these days.  The steel is tempered differently along it's length to make the shafts tough and strong, and the cutting end hard and sharp.  O1 is generally regarded to give a keener edge than A2 or HSS, although I think most turners will have to rethink their sharpening methods.  These tools are meant to be sharpened like a carving tool or bench chisel - shaped once in a great while on the grinder, and maintained with regular light honing on a stone.  The payoff is the smooth surface right off the lathe.

I ordered the smaller of the rectangular skews.  All the tools are around $80, but he said that's some kind of introductory pricing.  After I get it and have a chance to play with it, I'll do a little review.


I like it.  I'm no expert turner, but I use my skews quite a bit.  I've got a Sorby that's my go-to tool; tough, not particularly sharp, fairly cheap HSS tool.  I'll use it for roughing some blanks, and the coarse shaping of larger parts.  Where I really like this Glen-Drake skew is for fine shaping, slicing with the tip, and putting a nice smooth finish on a cylindrical or tapered part.  I keep it sharp and clean, and that's how it performs.  When I have a catch with a skew, it's usually the kind where the edge catches and spirals back along the workpiece, not the digging in the point and punching out a deep wedge type.  I have far fewer of those with this skew than with my Sorby, for whatever reason.

Tuesday, February 12, 2013

Cutting Concrete with a Regular Circular Saw

If you're nervous because all the contractors are using big expensive specialized saws, I'm here to tell you it's easy.  Just go spend $25 on a 7" diamond blade, put it on your regular circular saw, and slice away like you're cutting thick lumber.  If you have a nice saw, you might want to just buy a relatively cheap new one, or get a nice new one and retire your current one to rough work, because the motor will be eating a fair amount of grit.  I just cut up some pavers, and it was a piece of cake.  I was hesitant and thought such a cheap solution wouldn't work, but it worked great and the only issue is the amount of dust it generates.  Work with the wind at your back, wear a mask, and  use eye protection.  That's not some kind of liability disclaimer, just realistic advice.

There are three types of blades available at the borgs:  continuous rim, segmented rim, and "turbo".  I used the turbo type because it's supposed to be the best compromise between fast cutting and smooth cutting.  Just make sure it says it's for dry use or it won't last more than a couple of minutes.  You can also get the blades in smaller sizes for angle grinders and the like.

Monday, February 11, 2013

Installing Turf Block Pavers

I park one of our two cars in the back yard.  There's no driveway, I just drive it up over the curb, across the grass street strip, over the sidewalk, and through a gate.  Classy, I know.  I only drive the car about once a week, and it's only a temporary thing until I get a new garage built or something.  I've been temporarily doing this since 2007...

The part where I drive across the grass strip has worn into a couple of muddy ruts, so I looked into some paving options.  Poured concrete would have been the easiest and cheapest, but turf block / grass block is less obtrusive, easily removable, and doesn't create runoff.
The blocks are 18" x 24" x 3-1/2", and I got them at Mutual Materials in Clackamas for about $8 each if I remember right.  I laid them out and scored the ground to mark the locations, and excavated down about 7" from a levelling board I laid across the area.  Then I laid down several inches of 3/4"-minus crushed rock, and packed it down with a hand tamper until it was 3-1/2" below my board.  A little 1/4"-minus on top gave me a layer to set the stones into.

The stones had to be cut to make a clean fit in the 7' long strip.  I cut them with a $20 "turbo" diamond blade in an old 7-14" circular saw I keep for this kind of rough work.  Trying to cut masonry with something other than a chisel was a new thing for me, and aside from being a dusty mess, it was a piece of cake.  Advice from a newbie to anyone trying this:  cut the top / show face of the masonry first, about half way through, and then flip the stone and finish the cut from the back.  The last bit always breaks off, and you don't want that to be a corner on the top.  And just go slow.  Let the saw find it's own happy cutting speed, and don't push on it.

Cutting the pavers with a diamond blade in a circular saw is easy

I filled the holes in the pavers with compost and soil, and I'm going to plant sedum in them.  It will take the summer heat and drought better than grass.
Finished Turfblock Strips

Monday, January 7, 2013

DIY Angle Gauges for Cutting Drywall

You don't have to be that accurate when cutting a piece of drywall / gypsum board / sheetrock.  Within 1/4" is usually fine.  Mud and tape covers a lot of evils.  Fitting pieces in odd-shaped areas like angled soffits or ceiling transitions, or anywhere in an old house can be a real challenge though.  When I refinished our baby room, I don't think there was a single square corner in the whole job.  After cutting a funky piece based only on the dimensions and finding it was off by over an inch, I went down to the shop and made these.

Three foot angle gauge for drywall
Simple but effective lock mechanism
They're nothing more than a couple strips of thin plywood, held together with a short carriage bolt and a wing nut.  I glued a patch of 160 grit sandpaper to one of the pieces at the joint, which really helps them lock together when the wingnut is tightened.  I made two sizes to accommodate my work, one about 3ft long, and the other about 18 inches.
To use them, just hold them up against the corner you need to fit, and then lock the angle.  Lay the gauge on the piece of drywall and mark your cuts.  By taking angles at all the corners and making sure all the angles and side lengths were correct, I cut a lot of weird triangles and trapezoids to very close tolerances.  Super handy.