Sunday, March 16, 2008

The Fear and Loathing In My Basement Workshop

Today, Sunday, I decided to do a job I've been putting of for a year.

Two years ago I built a display case for a friend who sells pewter jewelry and statuary at Renaissence Fayres, conventions and the like. He had broken his roatating case he used to display small pewter amulets and I said I thought I might be able to make him a new one. A year of design doodling went by and then I actually got my finger out and built a rather nice hexagonal case. He'd asked for a square one, but I pointed out that with a hexagon he had about 25% more display area for less footprint on his table. You can check this for yourself with paper shapes - the space you need is a circle traced out by the corners. Given that any empty space will silt up as the day goes on, a square case would soon end up non-rotatory.

I built the case out of maple wedges, and it loked good. The guy was absolutely flabbergasted when he saw it and I felt good, even though I took so long to get it to him he had already set up at I-Con (where we see each other each April) and so couldn't use it that year.

The next year I expected to see it in use, but disaster had struck. It seems my joinery was distinctly second rate, because during the time the case had sat in storage (in a damp garage, but it should have been good even so) the top cracked along one joint. I took it back and vowed to fix it.

A year passed.

Today I decided to try and repair the wretched thing. I undid the truss rod that ran from the top to the base and lifted off the top. the rest of the case promptly fell into its component parts. Magic. Now I had a fiendish 3D jigsaw puzzle to do on top of everything else.

A couple of taps with Mr Hammer and the top separated into two halves along the broken joint. I peered at the edge closely, and divined the trouble: the joint was not square on either side, rather what I had suspected.

My miter saw was clearly slightly out of adjustment such that when the cuts were made they were on a slight bevel. Not much, but the damage doubled up on each joint on account of the bevel being on both faces.

I had a think and came to the conclusion that I would probably have to replace one wedge of the top, and set out to Home Despot to purchase a small length of 4 inch wide maple, a stock item. I took with me a sample left over from the machining of the original wdges that I would need to set up the tooling for the router. Each wedge requires a number of machining operations to accomodate the glazing and the central cylinder, and I long ago lost the measurements I used.

It should come as no surprise that the first obstacle was that the 4-inch wide maple stock was now of a different width to that I had used two years ago.

"How can 4 inch wide wood be anything other than 4 inches wide?" I hear you ask in a bewildered tone.

That's easy. The measurements used on any machined lumber, from the nasty 2x4s used to make houses to slabs of oak used to make sideboards are "nominal", which is a trade phrase for "lies". 4-inch wide lumber is, or used to be, about 3½ inches wide when measured with a ruler. The lumber industry claims this is because the wood started out as 4 inches wide but some gets lost in the machining. It should be obvious they play the same mendacious game when it comes to thickness too. Today I discovered that the guys who set up the planers at Weyerhouser or whoever Home Despot is using these days for hardwood have added, which is to say subtracted, another 1/16th of an inch or so. All the measurements will have to be changed to match. Not only that, the standard length appears to be 24 feet. I found one seven foot length but it was bent as a donkey's hind leg and therefore useless for the task. Even though I could find enough straight stuff to make the wedges from, I'd need the bloody plank to be flat so I could cut grooves in it. Putting warped wood though any of the router table operations I would need would be akin to playing Russian Roulette with an automatic pistol, since violent kickback1 of the workpiece is guaranteed under such circimstances.

I glumly surveyed my options, when suddenly I was bathed in sunlight and a heav'nly chorus rang in the air. The Rule! I had forgotten The Rule![

The rule says that for every job I have to do, I am entitled, nay, obliged to purchase a new tool to aid in the completion of said job, and that refusal of requestors of said job to countenance tool acquisition is grounds for refusal to complete said job. I usually phrase it more succinctly as No Tool, No Job but this terse rendering of The Rule obscures one of the subtleties of it, namely that the aesthetics of The Rule require that the new tool should be used as little as possible. Nirvana would be to purchase the new tool and then finish the job without the need to actually take it out of the box (other than for the completely correct and understandable fondling that any tool owner occasionally feels the need to do with his or her new acquisition). The closest I've come to that was justifying the purchase of Mr Chopsaw for the Bannister Installation Project, taking it out of the box, making two cuts then putting it back in the box as Mrs Stevie hopped up and down in appoplexy and screamed "THAT'S IT?" at volume number 11. It was a great triumph. I digress.

I could use The Rule to justify the purchase of an oscillating spindle/belt sanding table, which would allow me to properly joint the wood and perhaps salvage the pieces from the original structure rather than make them over again. From Mr Brain to the shopping cart, twas but a short dash to the tool department, and to cut a long story slightly less long, my workshop now has a rather nice sanding machine in it.

I sanded the parts in quastion and they fitted up a treat. so well I decided to fix every join on the lid, which required that I separate the pieces with a couple of taps of the hammer, sand them square and reglue them. Unfortunately, this also means the parts have all changed shape and I may end up having to remake them anyway to accomodate the other bits. Oh well.

One of the problems I had with the original was that the biscuit joiner couldn't grip properly on the small, odd-shaped parts and so the slots for the biscuits (little pieces of wood that span the joint and give it strength) couldn't be used. I decided to strengthen the joints with plates of metal screwed across the joints on the underside where they won't be seen. This is where fiasco struck.

I cut some lengths of metal and went to chuck a drill bit into my drill press so I could make the holes fo rthe screws. The chuck wouldn't open wide enough. This was odd because the drill was about 1/8th of an inch in diameter and the chuck is supposed to open up to five times that. It is the primary reason I bought that model of drill press. I messed around with the chuck for a bit, during which time it loosened up, then bound up again. I oiled it, but no joy. It felt like maybe loose metal had gotten into the mechanism (not possible, but that's what it felt like).

I was well annoyed. I don't use this tool, or indeed, any of my tools enough for them to start breaking. The only tools that I've had bite the dust have both been small drills. The Black and Decker gave years of good service and burned out because it was used al the time for every damned job I ever did. The Ryobi one quit because it was a piece of junk. 7½ volts, with naff battery technology. It really had no chance.

But the drill press? It has seen only light and sporadic use, partially because the quill runs out by a thou and can't be used for doing things like long boring operations2 or attaching a mortising bit3.

I heaved a sigh of annoyance and decided I would have to break the taper between the arbor and the quill.

Why are you looking so cross-eyed? Are you not conversant with the workings of a drill press? Okay, one crash course coming up:

The drill press consists of a motor that is stationary and which transmits its rotation through pulleys and belts you can jigger with to select different speeds at the drill bit, 15 speeds in this instance. It's a bit like a racing bike chain and gear set, except that there are two belts instead of one chain and none of the speeds duplicates any other like they do on so-called twelve speed racing bikes that only have about seven gears, and you have to dismantle the belts and move them by hand instead of having a little lever next to your crotch to move the chain about. Also, there is little chance of getting your trouser leg caught in the drill press gubbins as they are up around head height, but on the other hand you can't use a drill press for a quick jaunt to the shops. Where was I? Oh right.

The rotation is fed to the spindle, which is hollow with a taper machined into it, wide end pointing down towards the table. The taper is a machine standard, called a Morse taper. The name is a coincidence. It has nothing to do with David McCallum on the Titanic in A Night To Remember. The spindle is housed in a bearing/tube assembly called the quill. The quill holds the spindle steady while it moves up and down when the operator rotates the handwheel. This is how the drilling is done. A rod of metal called the arbor is inserted into the spindle. It has a matching taper, and a nice tight joint can be made just with friction between these two precision machined parts. The other, lowest end of the arbor is also tapered. Onto this taper is pressed the chuck, a three-jawed vise that holds the drill bits centered. Here endeth the lesson.

The mechanism in the jaws of the chuck was what had frozen up, but at this point I was still hopefull that a little WD40 and some elbow grease would loosen it up. And what do you know? A mere five minutes later and it was frozen so solid it could have had mammoths preserved inside it.

I tried turning the chuck key to no effect. I tapped the jaws gently with the hammer and got some movement, but the chuck was just taunting me before it set solid again. I tapped the jaws some more, but that was all she wrote. I tapped harder. It was about this time when Mr Brain informed me that the chuck was certainly a lost cause and that I would now be better employed getting upstairs and googling for a new one. I tapped the chuck a little harder with the hammer but nothing budged, and a momentary surge of pure rage surged through me, obliterating all rational thought for a few seconds as I contemplated the treachery of this underworked tool in my moment of need.

Letting loose a stream of the most potent words of power in my lexicon I belted the bloody thing so hard with Mr Clawhammer that sparks shot off it. The rage passed in the catharsis of the hammering and I set the instrument of my new found calm on the bench. Then I set the arbor carefully in the bench vise, gripping it by the little tag on the end put there for such purposes, and belted the chuck's rear with the hammer until buggerybastard paperweight flew off the arbor. I inspected the arbor for damage (none, than Azathoth), grabbed the handbook and recorded the model number of the drill press and the chuck and prepared to do battle with the interweb.

I should point out that a good part of my anger was because Sears, the people who sold me the drill press about 13 years ago, long since stopped selling this model, and although Sears used to have a reputation unrivalled anywhere in the world for having spares for tools long after they had gone out of production, that reputation has been steadily eroding for years. On the off chance, I loaded the Sears website and, after a couple of false starts, found the parts department of it.

Whereupon, on typing in my drill press's model number, up sprang a list of parts and diagrams for it. Some of the bits were flagged as "Discontinued" but not the chuck, chuck key and bearings. The chuck was priced to sell at around $65 (no silver lining without a cloud) but I was over a barrel. The bearings I bought because it has been suggested to me that the wobble in the quill might be due to a duff bearing. It's worth a try. The chuck key is just becuase there's little point chewing up a new chuck with an old chuck key. The original isn't so badly worn I'll throw it out, but it makes sense to buy a new one now while they still have them.

  1. An exciting part of powertool usage in which all the energy of the high-speed whirling bits of razor-sharp steel is converted into kinetic energy in the workpiece, which uses this energy to seek its freedom in unexpected directions. It is not unusual for pieces of the handyman to be torn off or poked out at this time, which adds a frission of terror to any job
  2. boring long holes down poles rather than driving people nuts with endless droning on about uninteresting stuff
  3. I nearly went mad from frustration when it became obvious that the mortising attachement was right out - it is one of the most basic conversions you can do with a drill press and the other big reason I bought it

No comments: