Wednesday, December 09, 2009

Clamping challenge

Clamping the boxOnce I was comfortable making dovetail joints, a process that took another test piece and quite a bit more chiseling, work started on the carcase of my tool chest.

First job - prepare the wood. While I had planned down (in a machine thank goodness) the oak for the outside, so much wood had been removed that the leftover plank threw a strop and warped slightly. Luckily I had been paying attention when first instructed in the art of the thicknesser I'd remembered the instruction not to take more than 10mm off any wood, "or it could move". My wood certainly had, on a flat surface it wobbled. Not much and a skim of a couple of mm sorted it out but this prompted me to get on with the other lumps of tree and get them within spitting distance of the right thickness so they too could settle.

Anyway, with the plank ready for use I carefully marked and then cut my dovetails. Things went well and I was chiseling away quite happily. The fit of some joints was best described as "snug" but they could be persuaded in. Handy hint: don't bash the bits together with a mallet, it attracts attention in the workshop. Use the vice, it's much quieter.

Before assembly, the front and back edges were routed out to give me a rebate for the plywood. It's a job that takes longer to set up than to do but will make the resulting box look better than it would if I just nailed the ply to the sides.

Once all had been glued up, I needed to smooth down the joints. My preference would have been a sander but apparently you are supposed to use a plane for this job. Well that's what proper cabinet makers do.

So the box had to be held in place which is where the problems started. Gripping a box this big isn't easy and as you can see we had to improvise with 3 sash clamps and an off cut to get the thing fixed to the bench.

After this I attacked it with a plane. Attacked is the right word. I don't know if it was the wood, the plane or that I'd started a new job the day before, done 12 hours work that day and hadn't been sleeping properly, but things just didn't go well. The blade would shave the wood and then dig in for no reason. By the time I'd worked over three sides my previously smooth sides were like a rutted field. I knocked off early before I did any more damage.

A couple of days later, at home in the garage, the box was clamped to the bench and worked over again. First with a plane that I had freshly sharpened which did improve things a little. Then with the sander and gradually finer grades of paper. This improved things a lot. Cabinet makers know nothing. Machine tools are better.

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