Tom's Workbench

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Archive for the ‘How-to’ Category

The right grind

Wednesday, February 1st, 2012

I’m always amazed when I go to a specialty coffee shop. Not only is there a bewildering array of beans grown and harvested from areas around the world, there are also numerous levels of roasting that have been put on them to create a different cup of coffee. How about a light roast from Kenya, or a darker roast from Hawaii? And, once I make my choice, the questions keep coming at me… How do I want it ground? For a drip machine? A French press? Espresso? At this point, I’m usually looking for someone to just hand me a steaming cup of Joe and send me on my way.

When it comes to sharpening, the question of grinding comes back into play. Flat or hollow ground that is. And, depending on how you sharpen, you will come to understand and appreciate the difference.

Let’s start at the beginning, shall we? When a woodworker sharpens a chisel or plane iron, you are looking to get an edge where two faces of the tool intersect with zero radius. One face is the flat back of the tool. That’s why it’s critical to get the back of a chisel or plane iron flat and smooth, so it will intersect with the other side as cleanly as possible.

That other side, of course, is known as the bevel. Depending on the purpose of the chisel or plane iron, that can be any one of a number of angles. For most bench chisels, that is somewhere about 25 degrees.

Now, there are two different ways a factory – or a woodworker in his or her shop – can get a bevel into that shape. That can be done first on a flat sharpening medium. In that case, the bevel rubs against a flat surface, grinding away steel from the bevel from tip to heel. This is how people who use stones or flat-platen grinding setups create their bevels. Some experts say that because this is a tough way to sharpen and hone an edge, because at every phase of the sharpening process, you are abrading the entire bevel, a relatively large area to grind.

To help make restoring the tip of the bevel an easier task, many people who flat grind will take a few passes with the tool tipped to a slightly higher angle. What this does is polish just the tip of the tool, creating a very narrow band of honed steel at the end. This is known as a microbevel, and it can make keeping your tool sharp easier if you are going on the flat.

Now, if you are using a wheel to grind your bevels, you are looking at a hollow ground. When I’m working with a tool at my Tormek, The bevel of the tool is rubbing against the surface of a large-diameter wet grinding wheel. As the bevel touches the stone, it’s working against a rounded surface, which means if I have my guide set properly, the middle of the bevel is going to make contact with the stone first. In order for me to grind the bevel from tip to heel, I have to remove more steel from the middle of the bevel. This means that the bevel is being ground into a slightly concave shape. Remember, we’re not talking about a huge curve here… the surface of the bevel is relatively small compared to the diameter of the wheel.

This hollow ground, though, provides an interesting effect should you want to hone the tool on a flat medium later. As you sharpen the bevel, it will make contact on both the heel and the toe, removing material in two bands. This effectively reduces the amount of contact with the sharpening medium, making for easier honing later.

Are microbevels or additional flat honing required? Nope. A sharp edge will slice wood beautifully.

Which leaves more time to take a break and sit down with a nice cup of coffee.

 

Mitered door frames

Wednesday, January 18th, 2012

I’m currently in the middle of a project, and I needed to build a set of inset frame and panel doors. Time to break out the cope and stick door frame bits, right?

Not so fast, bub. I thought this project would look better with some mitered door frames instead of the plain old plain old. To make this happen, I reached back for a trick I had used on the first project I built with doors – a mitered door frame.

As you can guess, each of the four sides of the door are joined at the corner with a 45 degree miter joint. A few benefits of building a door this way are that you don’t have to buy specialized router bits to do the joinery – a table saw, miter saw, hand saw and miter box or any other method you use to make crisp, accurate 45 degree cuts will fill the bill. Also, if you want to rout special features into the face of the panels (Maybe a bead on the inside edge and other fancy molding profiles), when you cut the miters, the design will wrap all the way around the frame. Also, if you carefully measure the inside opening, the long side of each mitered piece will be the exact measurement of the opening you are trying to fill. No crazy math with subtracting style width and adding on tenon length.

The downsides? Your miters have got to be very accurate, or you are going to spend a lot of time and use a lot of wood putty to make the piece look good. Also, miter joints are very weak when compared with other traditional joints – and they slip like crazy when you try to glue them up. That’s why some method of reinforcement when building a mitered door frame is a must. And, if you have to fine-tune the door to fit the opening, you have to remove equal amounts from each side to maintain that crisp miter point (you can fudge a little, but not too much).

For my doors, I milled a piece of tiger maple for the door panel and milled up the door frame pieces out of walnut. After plowing a groove in the edge of the frame pieces (using my table saw blade and moving the rip fence to center the groove) and mitering them to size, I laid everything out on my bench. It looked pretty good. After I rounded over the inside edges of the panel, I moved to the next step.

For reinforcement, I went with a pair of dowels in each corner. I could have gone with biscuits, pocket screws, splines or the like, but I have my fancy Joint Genie dowel joint jig, and it took mere minutes to get things lined up.  Notice how I kept the dowel holes away from the outside of the miter, lest I drill all the way through the board. I was going to slather on the glue really well, and I knew the dowels were going to hold really well.

Of course, when you are assembling a frame using dowels, you should join two opposite corners together first, and then bring those two halves together… don’t ask me how I came across this valuable piece of information…

The result? Not too shabby. The door needed some sanding to even things out and get the glue marks off of it, but, all in all, it wasn’t a bad little door to work on.

What is it a door to? Well, you are going to have to stay tuned… I should have the entire project put together this weekend, and you’ll see it this coming Monday…

 

Strop! In the name of love

Monday, January 9th, 2012

I remember the first time I was able to get a hand plane to work properly. I had this nasty old Stanley No. 5 that I bought from eBay, and I had spent a lot of time cleaning rust and other crud off the body, freeing the adjusting screws and just cleaning the heck out of things. I also took the time to sharpen the iron, reading the instructions on how to do the deed at the bench while I worked on the edge. When everything was back together and the first curl popped off the board, I knew I was in love.

Unfortunately, I didn’t really like sharpening at the time, and the job I did was barely passable. And, after some serious use, I struggled to get things sharpened. After that experience, I shied away from hand planing because I didn’t ever want to go through the whole process.

Since those early days, things have certainly changed. I have improved my sharpening technique and, with the Tormek setup, I can get things done in very short order. The thing I did discover, though, was that while using my chisels and planes, the edges never really got totally dull. Not like a sit down and spend some serious time sharpening kind of dull, just a little difficult to push. That’s when I discovered the joy of stropping.

What exactly is stropping? Well, when you sharpen a blade, there are three phases of technique that you have to consider. First is grinding, which is working at the blade to recreate or reshape a bevel. If you get a beat up old plane, you may need to grind that edge into a usable shape. This is done with a coarse stone, a high speed grinder or some other contrivance.

Next up would be honing. This is when you have the shape of the bevel, but you are looking to start refining the edge. This is typically done by hand on finer stones to get a good polish on the bevel.

Stropping takes honing to the next level. Rather than use a hard surface like a water stone or sandpaper on a piece of float glass, you use something a little softer – typically a strip of leather. The leather itself doesn’t do the cutting – there is a compound that you would rub onto the strop. It contains very fine abrasives and really perfects the cutting edge. Just a few passes is enough to do the job.

This is what barbers used to do to get ultra-fine edges on their straight razors. And, if you notice how a barber uses a strop, he or she never pushes the blade into the stroke, it is always pulled. This way, the sharp edge you are creating won’t slice into your strop, leaving a cut up mess.

I have a hand held strop made of leather glued to a wooden handle. This worked well when I was doing all hand sharpening, and I still use it when stropping smaller tools. The Tormek also comes with a leather strop wheel which turns on the same arbor as the main sharpening stone. The set up comes with a tube of stropping compound, which gets rubbed into the wheel, allowing for a nice polished edge.

While stropping after sharpening is a great way to go, I also have a trick I use in the shop. When I’m working with a chisel or a plane, I will stop from time to time and bring the blade over to the stropping wheel at the Tormek. Just a couple of seconds on both sides of the bevel, and I’m back to work, cutting well again. Obviously, it’s not a full sharpening job, but just as a chef may use a steel to hone his knife during meal preparation, it gets my blades back to a ready-to-roll state quickly.

 

Holding some runners

Monday, December 12th, 2011

You know, next summer, the city of London will be hosting the summer Olympics.  Since I saw my first Olympic games (the 1976 Montreal games), I have always been fascinated by them. I mean, how else can you get that many folks together from around the world without all the diplomatic saber rattling?  OK, there were a few boycotts through the years, but for the most part, they have been peaceful affairs.

I’m looking forward to seeing the competition. The swimming. The diving. The biking. The crazy sports. (When the games were in Atlanta, my brother went.  He said he couldn’t get anywhere near the track and field, basketball or volleyball events, but it was a piece of cake to get into the judo and weightlifting venues.)

One of the events I look forward to is the marathon. The men’s race is the last event of the games, and both the men’s and women’s races are interesting to watch. There’s endurance. There’s determination. There’s a surprising amount of strategy. And, I discovered during the 1984 Olympics in Los Angeles that you can’t help a runner cross the finish line. That’s when Swiss contestant Gabriela Andersen-Scheiss entered Olympic Stadium overcome with heat exhaustion and staggered to the finish line, refusing help all the way.  Talk about an indomitable  spirit.

While Olympic runners can’t accept help, I think most woodworkers need it – especially when it  comes to installing drawer runners. There are many purpose-built jigs you can buy to help make setting runners easy, there is one easy installation method that is so foolproof.. heck, I don’t know if I could foul things up with it.

When you build a plywood project like the pantry I’m building, you end up with a bunch of odd sized offcuts. Some are very small, while others can be long and narrow. I found a piece of 1/2 inch ply that was about five inches wide and six feet long. That was going to work for what I was doing. I took the piece and crosscut it to a length that represented the distance from the floor of the piece to the bottom of where I wanted to bottom of the uppermost drawer runner to end up.  I marked out the heights of where I wanted the other runners to end up for later, and clamped the plywood strip to the inside of the case.

Of course, you want to orient the jig properly as you work with it, so, it pays to mark which end is up on your strip. Trust me, pencils are cheap, and it’s better this way.

Once I had it set up, I laid the part of the runner that connects to the case side on top of the strip and screwed it in place. I then moved the jig to the other side of the case and attached the that side’s runner there.

The next step was to head back to the table saw, carefully line up the cut mark with the blade and crosscut it to the new length where the next lowest runner was going to have to be mounted.

The next steps are very repetitive. Mount both runners on the two sides of the case, cut the jig to the next level and you are off to the races.


This method beats the tar outta measuring, marking, cursing and the other fun and excitement I have experienced over the years trying to do this stuff. And, if you aren’t working with a plywood case, you could fish around at an offcut bin at the local home improvement center or purchase a piece of inexpensive particleboard to serve as your guide.

Either way, it’s a simple way to get things right.

 

The unheralded sharpening tool

Monday, December 5th, 2011

Sharp tools are important in any shop. They cut better, are much safer to use and provide hours of satisfaction.

And, just as there are many different woodworking personalities, there are many different ways to sharpen those tools. High-speed dry grinders. Water stones. Diamond stones. Slow wet grinders. Sandpaper… The list goes on and on.

The only essentials that are truly needed are a sharpening medium that is harder than the steel it is grinding and a way to put a consistent bevel on the tool.

Oh, that’s the tough part for any novice – and many experienced – tool sharpeners. Getting that bevel correct and consistent can mean the difference between a tool that cuts flawlessly and one that won’t work nearly as well. And, steeper angles make the edge stronger – so a 30 degree bevel on a mortising chisel will allow the edge to cut, but a 20 degree angle will chip like nobody’s business.

While you can often regrind a tool to change its bevel for a different task, most times you simply want to keep the bevel where it is and simply hone the blade to get a sharper cutting edge. And, there are plenty of gadgets and gizmos out there you can use to hold a tool at a certain angle, how sure are you that you have that angle perfect? A degree or two off can mean the difference between an edge touch up and the complete regrinding of the edge.

To help make things easier, you need to go a little more low-tech. In fact, you probably want to avoid the home centers and specialized woodworking stores altogether and head to the office supply places to pick up a permanent marker.

Yes, the tool your mom used to write your name on your underwear before sending you off to summer camp is a very handy accessory to have around when sharpening your tools. The ink is very durable stuff, and it writes beautifully on steel. While this may be nice if you are trying to mark which chisels are yours if you decide to go off to woodworking summer camp (does that stuff even happen?), it is a great characteristic for sharpening.

For a single bevel tool, think about how you sharpen it. First, you have to flatten the back of the tool, right? If you don’t it’s going to be mighty tough to get a nice, crisp edge on the bevel. If, before you attempt to sharpen your chisel, you color the entire back of the tool with marker and allow it to dry for a while, when you start to grind, the sharpening medium will wear away the ink in the high spots, showing how far out of whack your blade is. When I was sharpening a set of antique chisels I had purchased, it showed me that the tools were a little bit too far out of whack for my tastes.

Once you get the backs in shape, you will want to make sure you are duplicating the bevel angle already on the tool (unless you are trying to change the angle altogether). So, you simply flip the tool over and color the bevel with the marker. Once you allow it to dry, it’s easy to check at what angle you are grinding.

Even on my Tormek, with its fancy tool holders and angle setting guide, the instructions advise you to use the marker method to color the bevel. From there, I mount the tool into the guide and press the bevel to the stone. Using my hand, I spin the stone maybe one turn. That simple turn will show me exactly where the bevel is making contact with the stone, and whether I need to make any adjustments to get the bevel lined up correctly. This method works very well for freehand honing as well. In fact, by using the marker as technique feedback, you can train yourself to set the proper angle without any guides. It’s that simple.

When you are done with the grinding, the edge should be nice and shiny, with all of the marker worn off. By that point, you will be ready to add your microbevel – if you use one – and get back to the bench.

Not bad for an inexpensive sharpening aid!

 

Silly rabbets…

Monday, August 15th, 2011

OK, so now that I’m back on track with this bookshelf project (doesn’t it seem like this project is taking longer than it should?), I am moving on to the joinery.  When last I left the frames for this project, I had cut the dadoes and grooves in order to put the shelves into place.

For the upper and lower shelves are a piece of cake – 1/2″ wide parallel grooves at 3/8″ deep along the length of the top and bottom boards to capture the shelves.  Since there is no problem with a cross grain situation, I will be gluing the shelves along their entire length to get the best contact possible.

Cutting these rabbets was pretty straightforward, but it did require a bit of care. I am having each of the shelves extend past the front of the unit by one inch.  This means that I had to hold the rabbets back that one inch from the front in order to keep the that extra material there to work with.

I went with my hand-held router and a rabbeting bit to cut the joints, and they were plenty easy with my DeWalt router. I held back from my one-inch line from the front, and simply squared the rounded edge the router bit left with a sharp chisel.

These were the easy ones.  I’m now going to figure out how to rabbet out the two middle shelves for the unit.  They are attached to the bookshelf sides with a groove that spans both the front and back uprights, and the front upright is at a slant, meaning my rabbet will need to have angles cut into it to match up with the sides…

This should prove to be  pretty fun…

 

My abrasive personality

Wednesday, August 10th, 2011

Being originally from New Jersey, I have many mannerisms that people here in Florida either love or hate. Sometimes, I have to speak a whole lot more slowly for folks to get me. Where I’m from, people talk fast because we have a lot to say.  Sometimes, people tell me I drive too fast. Well, I learned how to drive in a place where people drove with a purpose.

And, there’s something about my personality… I’m not sure what it is… but it makes some of the folks down here think I am obnoxious. Abrasive. Quick to judge.

No way… not me.  I’m as easy-going as the next guy.

But, there’s one thing that has me seeing red and using colorful language as of late… I’m still having issues with my panel glue ups. Even with very straight edges, biscuits and cauls, I still get the occasional slipped joint. Oh, my technique is so much better now, and the steps are no where near as bad as they used to be… but they are still there.

In the past, I have used my jointer plane to cross plane my boards to get them to size. But now I’m relying on an easier technique – for me at least.

Welcome to the world of abrasive planing.  That’s right, I’m using my belt sander to get my boards smooth and level when there are issues. Why the belt sander?  Well, I seem to have a whole lot less splintering or tear out to worry about when I use the sander.  And, with the right grit belt, the work seems to go faster.

I have been starting with a 50 grit belt.  “WOAH!” you may be thinking. Sure, that’s kind of a pebbly grit to be using on fine boards, but, believe me, sanding is all about starting with the right grit and working finer.  If I had started this with a 120 grit belt, I would be out in my shop forever trying to get even the smallest imperfections out of the glue ups. With that powerful grit, I can take the board down to smooth (well, level… smooth is next) in very short order.

My method starts by working across the grain…

“GAAAAAAK!”

Would you please chill out?  Shesh… By working across the grain, it’s sort of like planing across the grain… my goal is to get all of the boards in the glue up level to each other.  If I sand with the grain, I’m just going to get individual sanding rows nice and flat, but the board may still be out of flat across its width.  Sand back and forth across the entire width of the panel. Don’t leave anything out… you don’t want to wear channels out where the glue ups are.

Oh, and remember that the other nickname for this tool is the belt saw… so never leave it in one place or you will dig a hole clean through your board. And, those kinds of sanding divots don’t come out easy.

Once I get things flat across, just as you would use a jack plane, I have to then go across the board diagonally. This helps even out any spots that may be higher than the others on the flattening operation.

Finally, I make a few passes on the board from one end to the other parallel with the grain.  By this time, any irregularities in the board are gone and the panel is nice and flat.

From here, you could go and progress through the grits… 80 and 120 in the belts, followed by 120 and 180 with an orbital sander.  If that’s how you work, more power to you.  But, I’ve found that a hybrid approach works well for me. The first thing I do is brush any sanding grit off the boards. Then I take my Veritas Low Angle smoother, get it set for a fine cut, wax the sole and get at it.  Usually two passes on the board gives me nice smooth results, but the first pass is actually pretty darned good.

Is this the ideal situation?  No.  Gluing up by boards perfectly would probably be a much better solution.  However, if you do have some irregularities, this isn’t the worst way to work.

What? You got some kinda problem wit that?