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How to Make a
Set of
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A serviceable set of school size blocks can be made at home by a practiced woodworker. Aside from gathering materials, expect to spend 20-40 hours at this. We give directions for making hardwood blocks but the instructions can easily be adapted to making blocks from SPF stock from your local lumber store. The plan is based on our "Base Set A," and a contents list can be obtained by going to the List of Pieces for this set and printing it. Other sets are similar, but you will have to recompute the required quantities of lumber. Buy Stock If you value your fingers, forget the idea of using all that lovely scrap you've been saving. We see this foolish idea repeated over and over; it's an invitation to injury. Buy about 35 board feet of Kiln Dried, 8/4 hardwood lumber and about 8 bd. ft of 4/4 from your favorite hardwood dealer. #1 and #2C should do it. If you can obtain 7/4 this will be cheaper, but 6/4 is usually too small unless it is very robust. If possible, get the 8/4 lumber pre-planed to about 1-5/8 (both sides) or 1-3/4 (one side). Get the 4/4 planed to about 7/8. Hard Maple is the best. Soft Maple will work but this may vary considerably in quality - particularly Silver Maple. Oak and Walnut are pretty porous. Beech is good, but watch for checking. Cherry is good. Poplar is good but a little soft and often streaky. Sycamore is excellent but often badly dried and with a lot of tension. You can use anything, but consider the investment in time and effort. This should cost well under $200.00 for Hard Maple. Using SPF and Other Woods You can also use SPF (Spruce, Pine, Fir) from the lumber store. It's cheap and you can obtain the same footage for around $50. However, this lumber is always very, very wet (even if it says, "kiln dried") and your blocks will shrink and warp when you are finished. If you sticker it in a pile, and leave it to air dry for a month or so in a warm, dry place it will shed some of this moisture but it will still shrink somewhat. The standard for calling SPF "kiln dried" is utterly different than the standard for hardwoods - so don't be fooled. SPF (particularly Fir) is also considerably more likely to produce splinters. Whereas hardwood knots are usually sound, SPF knots are usually loose and must be eliminated. Seek out lumber that is pretty straight and has the fewest knots. Needless to say, you shouldn't
use treated lumber
unless the kids have become a bother. Be cautious about imported
lumber. Rubberwood is
universally soaked in Borates, chemicals that are lethal for cockroaches, and
though it's not considered hazardous to young
children I wouldn't use it. Rubberwood is also derived from actual
rubber trees and could potentially adverse reactions to latex from
those who allergic. Animals, such as horses, react badly to
sawdust from most nut trees including Walnut, Butternut, and the
like and these woods are reported to cause some reactions in humans. Use your planer to plane the thick stock to 1-3/8. Plane both sides and use a caliper to get it exactly the correct thickness. Use your planer to plane the thin stock to 11/16. Use sharp new blades in order to avoid sanding. Do not trim off the snipe at this time as you will also be using the planer to plane for width at a later stage.
Using a sharp rip blade on your table saw, rip the following stock. You should have plenty of lumber to do this and you can easily end up with extra if your original lumber was high quality.
Take pains to make sure that your saw blade is exactly perpendicular to the saw top and that the material is lying flat on the table. If the material is at all warped, cut it into shorter lengths. In order to plane the edges you will have to rely on the ripping having been square. Angled cuts will persist, even after planing in the next stage.
Plane the edges Use your planer to plane both edges of the wide stock stock to 2-3/4. Use your planer to plane both edges of the narrow stock to 1-3/8. Be very careful with the wide, thin stock as this has a tendency to tip in the planer. If you've gotten this far you should have four sizes of S4S stock, with smooth, perfectly square faces. At this point be sure to cut off any snipe on the ends as this will haunt you if it gets mixed in with the blocks. Rout the edges Using a small rounding bit on a router or shaper, round or chamfer the edges of the sticks. This is easiest on a small router table, but it can be done by hand. If you use a router table, be sure to use short fences as longer ones will push warped material away from the bit. Use a sharp, carbide bit and watch the direction of the grain to avoid chip-out. It is also possible to use a belt sander for the same purpose. Try to establish an even bead with a small radius (about 3/32"). This is the place where you need to be most vigilant about potential splinters in your stock, so inspect your final work carefully and sand any proud slivers. Use chalk to mark for elimination any sections where a splinter has made itself apparent and sanding won't remove it. Customers are usually confused about splinters and suppose them to be the edge frass that sometimes flops around on the end edges after cross cutting and sanding, but this is harmless. Free floating splinters can't leap up and penetrate the skin even on little hands. Real splinters are intact tips projecting from the blocks in the long dimension where the grain is separated slightly. This will hardly be a problem with maple as the cells are too fine, but more substantial splinters may occur in Oak and other woods with bigger cells - particularly Pine and SPF. Pause You should now have molding more or less in the amounts given above. Chop the Blocks Chop the blocks to length on your table saw with a crosscut sled or a miter bar using an ultra sharp crosscut blade (about 60 ATB teeth for a 10" saw). The object is to make the requisite number of 22 inch, 11 inch, 5-1/2 inch, and 2-3/4 inch pieces. You can eliminate all of the knots if you wish or, if there are sound knots, leave them. In general, a simple miter saw won't work very well as it tends toward a lot of edge chipping. Some of the new sliders may work better, but a table saw is probably the best. A radial arm saw may also work, but most of them have a lot of slop in the track. A carefully set stop is required for repeating lengths. Take pains to set this correctly and to fasten it firmly to the table top as it will get "tapped" quite a bit and this has a tendency to move it. There are some inherent dangers when cutting lots of identical rectangles with a miter bar- particularly small ones. Use a tall wooden backstop attached to your miter bar and be sure that it is flat. If it is at all concave, the blocks will tend to pinch inward just as you are finally finishing the cut, the blade will pick up the block on the blade and hurl it toward you. It is best to provide a back stop that is quite tall (just small enough to fit under the blade guard lid when pushed forward). Remove or disable the anti kick-back pawls and replace the guard lid with a larger one. Slit the miter bar backstop specifically for this job and also use a fresh, nicely slit zero-clearance insert in the table top. The tall backstop will contain most flying blocks (though they may ricochet around a bit) and the insert will reduce the chip out on the edges. Clamp a fixed length stop to the saw table top for cutting identical lengths. You may have to undercut the backstop to clear the length stop. Safety glasses are a must. You should easily obtain the following (more or less):
These numbers are a minimum based on the assumption that you are eliminating all knots and dings - if you are more relaxed about defects you can get many more blocks. Be sure that your lengths are exact, that your sled or miter bar is running exactly perpendicular to your saw blade, and that the blade is dead-on vertical. Test to be sure that two 2-3/4" blocks equal one 5-1/2" block, etc. Some additional 22" blocks are good if you have enough material, but avoid the temptation to cut too many big blocks and too few small ones. The small ones are generally more useful. Out of the 1-3/8" by 1-3/8" material (square columns) make the following:
Out of the remaining road plank and roof plank stock, cut the material in the proportions that you want. If you copy our list of pieces in the Base Kit A page, you will get a good idea of what you need. Be sure to cut plenty of roof planks as these are most useful in building complicated designs. Reserve blocks with a defect in one corner for making triangles. Reserve blocks with a defect across one face for wedges. Reserve blocks with a defect in the middle for making arches. The biggest mistake our customers make in purchasing block kits is to favor sets with mostly big blocks. This is fine for younger children, but to make really neat stuff a lot of little blocks are needed. Triangles, Wedges and other stuff Making these pieces requires a band saw
complete with a fence, a circle cutting attachment and numerous jigs.
The latter can be made by slitting a piece of Masonite to run along the
fence on your Band Saw and then gluing stops in place to hold a blank at
the proper angle. Using a jig
and the fence, cut triangles and wedges out of the 5-1/2 inch and 2-3/4 inch
blocks by cutting them diagonally. Because you want the triangles
and wedges to end in a blunted lip (about 5/32), the diagonal should be
offset at the lip edge by that amount. You can use the defective
blocks (above) for this. The resultant small half is usually thrown away. Round Columns These are made from dowels which can may be hard to find. The largest dowels in lumber stores are 1-1/4 (Ramen). Anything bigger is a special order. Sometimes Closet pole and banister rail material is available in 1-3/8. This is usually Fir, so be careful about splinters. If you have a lathe, here's your chance to make some spiffy columns out of anything you want. While you're at it, make a few onion domes for minarets and churches. Sanding Sand the end faces, sweep the end-edges, and bump the corners of the blocks to round them on a stationary belt sander or a belt sander held upside down in a vise. This is very time consuming and requires a sure hand and a good eye to do uniformly. It helps to have a dust collector attached to the sander and it's best to use a respirator. Practice on scrap for a little while. Be sure not to sand too much or your blocks will be shortened. Some people like a lot of rounding for reasons of imagined safety, but this makes blocks unstable, and I prefer them just slightly softened. This is a matter of personal preference. (It's more important, in the long run, to keep an eye on children at play and to nip naughty behavior in the bud). Finishing Unit blocks are best left unfinished. They can be painted with child-safe paints, but it is always a mistake to varnish or shellac them. In the long run this surface will chip, darken differently than where it is still varnished, and develop a mottled look that is extremely ugly. Exactitude Considerable care should be taken to assure that sizes are correct and angles are square. Aside from driving around to gather materials, expect to spend quite a while at this task. Blocks are a wonderful toy for teaching math skills, but crooked blocks are likely to accomplish nothing but frustration. A certain amount of random error is allowable. Be safe with power tools and enjoy yourself. Don't tell anyone you've made blocks or the whole neighborhood will be stopping by . . . Or You can buy the molding from us . . . .
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