Introduction to building a set of composit forms.

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The first step to composite forms

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When I first read Wayne's book and considered building a set of forms for myself, I was concerned about the use of metal. I hadn't worked in metal and wasn't sure I could be accurate. Later I learned that a lot of rod builders started with wooden forms and many still use them. I considered my level of expertise and could see that I'd probably butcher a set of wooden forms in short order. (Practice makes this less likely. It was the practice I was worried about.) My solution was to build a set of composite forms using material I had easy access to. All the material in this list came from a hardware store, a home improvement store or a hobby shop.

There are two basic ways to built composite forms. Both are based on wooden forms. The addition of a metal planning surface adds durability. For the metal surface I've used both aluminum and steel. Both have their strong points and drawbacks. You'll find working with aluminum is different than working with steel. In some ways aluminum is easier to use, but it binds and fills files easier than steel. If I could get square edged steel strips I would go for them. Unfortunately most of the steel strips I found lately were beveled on the edge, meaning a lot of work (or a trip to the machine shop) to get the square edge you need for the "V."

The basic wooden form

I'm assuming you're making 5 ft forms. You'll have to adjust of other sizes.

Material I used:

2 - 1" x 2" x 6' milled red oak
12 1/4" x 2 1/2" carriage bolts. (machine bolts would work as well)
12 1/4" x 1 1/4" machine screws
24 1/4" hex nuts
24 1/4" washers
24 1/4" lock washers
24 1/4" wing nuts
2 9/32" lengths - thin wall copper tubing
2 5/16" lengths - thin wall copper tubing

Tools I used:
square 1/4 chisel saw at least 4 3" clamps adjustable wrench screwdriver. drill press drill bits drill vice or drilling jig * hobby miter box and saw	hammer small file course triangle file. block sander sand paper dial caliper depth gauge router ** V making tool * V making file *
( You'll make these.) *( not needed for the first design.)

Stuff to make

The tools you can't buy really are easily made. They'll only take a little while to build and once built, will last forever.
    -drill jig
    -V making tool (for the metal "V" grove)
    -V making file

Squaring things up
I started by building a jig for my drill press. My original attempt was to buy two metal 90º brackets. The problem is, 90º brackets aren't really 90º. I had to come up with another plan. Milled hard wood is square so I used it.

The Jig I ended up with is made of 1"x 4" kill dried, milled hardwood and a 1 X 6" piece of kiln dried, milled hardwood about 18 in long. I chose this material because it was the most likely to be flat and square.
I cut one 3" piece from each end of the 1" x 4" for back supports and used the rest as my back piece. I drilled three holes in a line three inches from the back, through the bottom of the base. I used wood screws to attach the back piece to the base. I then put the two 90º back supports I had previously cut against the back of the back piece, drilled holes through the back piece and into the ends of the two supports. I screwed wood screws into the holes. Next I put wood screws through the bottom of the base into the two supports. the last thing I did was drill a 1/4" hole for a bolt that I use as an attachment point to my drill press. This jig took little time to build and is very square.

That V grove

Creating the "V" grove can be easy or hard. It's up to you. The hard way to do it is to measure and file each side. That's because the chance for error is fairly great when you file a tapered "V" along two 5 ft pieces of wood.
I came up with a fairly simple way to get the "V" grove fairly accurate without a lot of fuss. The idea came from The best of the planing form in an article by John Bokstom, titled "Don't Laugh-It Works or How to Make Better Splines with Less Effort." The article described how to make outriggers for a block plane, to hold it square with the top of the form. I took the idea, simplified it and made a tool to cut my "V."

The tool's made with two pieces of 1"x 2" about 6in long for the outriggers and a 6in piece for the center.
The two outriggers are joined in the back by a 2" 1"x 2". The centerpiece is held on it's axis by a bolt, but is free to rotate up and down between the two pieces of wood. Part of a triangle file is glued to the center piece.

Make sure the bottom is flat and the back is square. If these two measurements are off the "V" grove will be off by the same amount.

Getting started

Once you've to the above built you're ready to start on your forms. Starting with the two 1x2 strips make sure they're square. If you buy good hardwood they should come from the mill square enough for your work. They should be strait. (That's hard to find, now days but do the best you can.) Cut to 5 ft.

Cut 12 lengths of 9/32 copper tubing and 12 lengths of 5/16" about 1 3/8" long. Put the 9/32" in the 5/16" for support. Put a 5/16" drill in your drill press and line up your machine vice or jig so that the 1" x 2" is longitudinally centered (on it's side) directly under the drill. Clamp both sides of both pieces to the drill press so that the bit falls app. 2" from the end of the work. After you've drilled the first hole place one of the 1 3/4" long tubing through the hole to keep everything lined up. Move the work 5" and repeat. Continue to do this until you've come to the other end of your forms. You should end up with 12 5/16" holes, starting 2" from one end and ending 3" from the other. This is the "pull" of the form

Now separate the two boards, remove the tubing and set it aside. Replace the 5/16" bit with a 1/4" bit and drill holes in one of the 1 x 2's app. 1" from and in line with the first hole. You can put the holes on either side of the original holes, it's up to you. This is the "push" side of the form.

My drill press with the two 1X2's clamped in place. Notice the clam at this end of the boards. Notice the bolts through the end that has already been drilled. All this holds the two boards parallel to each other.

You now have two strips of 1x2 5 ft long. One has a 5/16" hole drilled square through it every 5". The other has a matching set of 5/16" holes and has a set of 1/4" holes next to the 5/16" holes.

Now place the inside of the "push" side of your form (the one with the 1/4" holes) face up on your work surface. screw a 1/4" nut on a bolt until about 1/2" of thread is extending through the nut. Place the screw in the first 1/4" hole and draw around the outside of the nut. Repeat for the other 11 holes. When you remove the screw and nut you'll have an outline of the HEX shaped area you want to remove to counter sink the nut. Use the 1/4 chisel to create a hex shaped hole just deep enough to hold the nut.

Put a wing nut, lock washer, and washer on each machine screw push them into each 1/4" hole from the outside. put a nut on the inside and screw it into the hole. You've now completed the "push side.

Use a "hobby" or jewelers file to file a "V" in the each of the head of the 12 - 2 1/2" bolts or machine screws.

Now cut all the lengths of 5/16" tubing in half. Put one piece in each hole. put the 9/32" tubing over the 1/4" bolts (or machine screws). Push the bolt through both form half's from the "push" side. Put a washer, nut, lock washer and wing nut on the bolt. Continue until you've completed filling all the 5/16" holes. Hammer a small brad into the "V" you filed in each bolt. This will keep the bolt from turning on you as you tighten the forms.

Exploded cross section of the form (not to scale)

If the 5/16" bit you used is truly 5/16", you now have a set of planing forms that should be tight.

Adjusting the forms
You'll need a screwdriver and a wrench. Start by backing off the wing nuts. Make small corrections. After you make an adjustment to the forms, go back and visit the last station you adjusted. Adjusting one station can throw another station off.
To open, back off the nuts on the "pull" side. Using the screwdriver make about a 1/2 turn on the "push" side screws for each .010 inch you want to move the forms. If you have to open the forms more than .010", make two or more passes down the length of the form. Once you've got the form adjusted tighten the nuts on the pull side. Measure the V grove. If every thing's okay, hold the nuts in place with the wrench and tighten the wing nuts. Do the same to the other side, holding the screws in place with the screwdriver. Once you've got the wing nuts locked down measure the form again.

Once everything is tightened the forms will not shift.

To close, back off the "push" side screws until they are backed into the form. Tighten the "pull" side with your wrench. Measure as before. Once you get the forms adjusted, tighten the "push" side screws against the "pull side. Measure again. Adjust by turning one side or the other a fraction of a turn. Do the same to the other side. Once everything lines up lock in place with the wing nuts.

A look at Composite planing forms

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