Construction of the Baseboard
Step 01: On the topside of the 36"x22" particle board, cut a groove 1" wide and 3/8" deep, that runs the width of the board 2 inches up from the bottom. This is the track that the rail on the bottom of the "T" square will run in. Cutting this groove too deep will weaken the baseboard unnecessarily, and cutting it too shallow will not let the ruler mounted on the rail to rest on the top of the baseboard. Note: There will be less friction in moving the rail along the track if the rail does not touch the bottom of the track, but is instead, suspended in the groove by the ruler.
	Step 02: Mark the center of the baseboard from top to bottom. Centered on this line and 1" up from the bottom of the baseboard, drill a 5/16" hole through the baseboard.
Step 03: Pound the 1/4" jack nut into the hole.
	Step 04: Using a router with a 5/16" veining bit and a jig as shown. Cut an arc completely through the baseboard as depicted. The pivot point for your jig is the 1/4" jack nut installed in Step 3. The important part of this procedure is to have the arc with a radius of 18 1/8" so that it falls directly beneath the second hole in the cutting bar (refer to Step 6 of cutting bar construction). The jig itself could be made out of any piece of scrap material. I used 1/4" hardboard. To see an animation of the process click here. Slow modems may take a couple of minutes to load.


Complete step 5 using a router bit similar to the one shown below.

Step 05: Turn the baseboard over and widen out the slot cut in step 4 to a width of approx 7/8 of an inch and a depth of 5/16 of an inch.
Step 5 completed

Step 06: Turn the baseboard top side up again and insert the "T" square into it's track. With the square installed, measure 1/4" down from the bottom of the ruler and 5 3/8" over from either side of center of the board. Drill a small (1/8" or less) pilot hole through the baseboard. Make another pilot hole in the same position on the opposite side of the board.
	Step 07: Turn the baseboard BOTTOM side UP again. Drill out the pilot hole to a width of 3/8" and a depth of 1/2".
Step 08: Now once again from the TOP side of the board, enlarge the pilot hole to 13/64".
Step 09: Apply some silicon glue to the outside of the threaded insert and insert it into the hole on the bottom of the board. Repeat this procedure for the other pilot hole drilled in step 6.
Note: This next step involves modifying a washer such that it can be used to act as a brake to hold the "T" square in place. Two threaded knobs are placed through the washers and then screwed into the inserts placed into the board in step 09. The following picture details the end result. Note how the rulers slip slightly underneath the nylon washers. The knobs and washers I used are shown below.
Step 10: Make ruler brake washers. Although you could probably get by with just using a 3/4 " flat washer with any size hole that would accommodate the shaft of the knob, I used a shoulder washer and filed the shoulder down so that it was just SLIGHTLY narrower that the thickness of the ruler. The purpose of using TWO brakes instead of just one, is so that when the "T" square is all the way to the right or left - at least ONE of the brakes will still hold it. Now if you use an ordinary flat washer, when you go to move the square back to center, you will run into the washer.
The next step involves yet another modification to a piece of hardware so that the desired result is obtained. It involves making the screw assy that goes through the cutting bar at the top end.
Step 11: Install a 2" length of 1/4" x 20 all thread rod into a 1/4 x 20 wing nut. Prior to the assy - put a drop of high strength Loctite® Threadlocker (red p/n 27106) on the threads. You do not want this nut to come loose again!
	Step 12: File the wings of the wing nut flat. This reduces the height of the nut so that when place in the channel cut into the bottom side of the arc (step 5), it will not protrude from the bottom of the board.
Step 13: Place a thin nylon washer on the assy, and from the bottom side of the board, place the screw through the arced slot. There should be at least a 1/16" space between the bottom of the board and the filed portion of the wing nut. The wings of the nut should hit the sides of the channel such that the nut is not free to rotate completely.
	Step 14: From the top side of the board, place a nylon washer over the screw just installed in step 13. The size and shape of the washer is not critical but it should be sufficient enough to keep the spring from traveling down the slot.
Step 15: Place the cutting arm over the screw assy as shown.
	Step 16: Place one of the knobs on the end of the screw.
The last assembly to make is the knob assy that fits into the pivot end of the cutting arm.
Step 16: I couldn't find a ready made knob that fit my requirements, so I fashioned one out of a knob that was made to screw onto a 1/4" x 20 stud. The screw I started with was a slotted round head 1/4 x 20 x 2". Cut the screw length to 1 and 7/8 inch. Since the screw head was too large to fit in the hole of the screw, it was necessary to grind down the circumference of the screw head until it was .040".
	Step 17: Put some Locktite® Threadlocker #242 (blue) on the threads of the screw near the head and screw it into the knob until it is tight.
Step 18: Insert the knob through the nylon bushing and spring in the pivot end of the cutting arm as shown.
Your glass cutting system is now complete.
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This page or any code or content contained within, may not be linked or published elsewhere without express permission of the author. Author: Phillip D. Speed Copyright © 2001 [Pane In The Glass]. All rights reserved. Revised: June 24, 2006 .