I had a good idea (making a template)

[Greg Guarino]

I thought of this back on my last project, but hadn't tried it until today. I'm making a simple template to rout an arc into the top and bottom rails of my cookbook shelf units, but unlike the previous project, this arc is concave.

To make a long story short, I used a saber saw to cut it to within perhaps an eighth of the final line. Then I used a straight file to get pretty close. But for the fine tuning I took a block of scrap (actually chipboard, I think it may have been packing material) about 1" thick and filed one *edge* into a very approximate curve. I used spray adhesive to attach a strip of 60 grit sandpaper to the curved edge.

Now I had a block with a curved sanding edge, but a smooth bottom that made a 90 degree angle with the curved edge. With the mdf template flat on the bench, I was able to slide the block along the edge of the template, concentrating on the areas that weren't quite right, but keeping a square corner at all times.

This video is terrible (tip: don't rest the camera on the surface you're working on, especially if it's just a board on saw horses) , but I think it demonstrates the concept.

If the usual rule holds, here's where I find out that I have once again "discovered" a well-known technique. Anyone want to be the first to tell me?

[G. Ross]

Looks like an ingenious solution.

[Swingman]

LOL ... yes, you have indeed reinvented the wheel for one method of "fairing a curve".

But good thinking, and kudos nonetheless, as it shows an inventive, problem solving mind ... the hallmark of a better than average craftsman.

The method you discovered, using a curved sanding block held against a bench top, or flat surface (see below), in order to keep the curved edge perpendicular to the work piece face when "fairing", is a commonly used variation on the many different methods of fairing a curve ... and one of the reasons why we keep a spray can of Elmers spray adhesive handy. ;).

The same principle even has its modern, tailed, descendants in the form of table mounted "spindle" and "edge" sanders, both fixed and oscillating, that use the same principle to fair curves: a table, and the curved edge of a belt, and or sleeve, at right angles:

Same idea/method, except that you move the work piece against the "table", instead of the sanding block in the manual method.

Something to add to your wish list: a "pattern maker's rasp", which is another handy tool used in the various steps of making patterns/jigs to reproduce curves:

[Greg Guarino]

Our Motto: "We Reinvent the Wheel Every Day"

3M in my case.

"Tailed" = "corded", I assume?

descendants in the form

That I was aware of. My Dad has an old belt sander somewhere, and he's (sadly) long past using anything like that. I considered unearthing it and perhaps even fastening it down somehow, but my (re-)invention seems more controllable to me. The best thing about it is that it pretty much ensures a smooth curve if you make some passes across the full length.

On my list. This time I used a straight file to get pretty close to the line. It was too fine, in addition to being straight. Luckily this is a very gentle curve.

[dadiOH]

I doubt I will be the first but yes, it is pretty standard.

Another standard way is to put a router on a pivot, adjust the radius as desired and cut away. What you did is better if you are going to be making a bunch of identical parts at various future times; for a one time thing, I prefer the router way.

[Swingman]

While still a marketable skill in the manufacturing sector, "pattern makers", and their unique tools, doing work exactly like you were doing to make your "pattern" to use in your router jig, were once found in every factory around the country.

The Nicholson #50 is my preferred pattern maker's rasp. There is a #49, but the #50 makes a finer cut in both plywood and mdf, which is the material I use most of the time for routing jigs.

They're pricey, but when you need the results they give there is nothing else that will do the job as efficiently and effectively, and they are particularly handy when your curve is not a two point arc.

[Swingman]

Oddly enough, and on longer two point arc curves, like you would find on the bottom aprons of wide/deep casework, you don't even need a curved sanding block.

You can actually use a small rectangular sanding block, or a quarter sheet sander, and with a little bit of practiced carefularity, fair a curve nicely.

I often do this with my Festool DTS 400, with the pattern I'm working on in a vice.

Often times just getting as close as you can fairing, without being too anal, and depending upon the diameter of your router bearing, small irregularities in your pattern won't necessarily show up in the pieces being routed.

That said, I generally take my patterned curves to the OSS for that final touch up.

[Greg Guarino]

Have you seen this?

[Swingman]

Too bad, all good things must come to pass. Glad I take good care of my American made one.

Similar item as the older Nicholson's:

Also "Auriou", well know and respected French made rasps are expensive but high very quality:

There are also some German ones, pferd, or something like that?

Look at it this way, you pay for quality. If it costs $100 and it serves you well for 30 years...

[none]

On Mon, 2 Jun 2014 08:20:24 -0400, "Mike Marlow"

Considering the relative ease getting a divorce these days, there's quite a few men who don't feel that way ~ just as long as the prenup is properly done.