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Adjustment Knob

The adjustment knob is the handle that tightens the T-Slot Nut against the angle bracket, securing the angle head in the position that you require. There are various methods of making the adjustment knob, from turning to cutting the shape out of plywood. There are many variables, it is a case of deciding which is the simplest method for you.

 

Components for the angle bracket knobs

 

The photograph on the left shows two adjustment knobs that have been turned out of pine. The socket head cap screws are 1 1/2"x 3/8"-16NC.

 

A piece of 7"x 2"x 2" pine was set-up in the lathe and turned to an overall diameter of 1 1/2". The width of the handle was then marked on with a pencil at each end of the turned piece (3/4").

 

The material between the handle widths was then turned down to 7/8" diameter giving a turned up dumb bell impression. From the inside of the handle, mark a length of 3/4" with a pencil, this represents the length of the shank.

With all the lines marked on, remove from the lathe and trim to length on the bandsaw. Make sure to support the middle of the turned piece with a scrape of 1/4" plywood or MDF board. This will prevent the bandsaw from "grabbing" when the blade cuts finally through.

Alternatively, cut to length with a handsaw. The total length of the handle should be 1 1/2".

 

Now that we have two blanks for the knobs, clamp the shank of one in a drill press vise. Set-up the drill press with a 9/16" spade bit and adjust the stops on the drill press so as to only counterbore the handle to a depth of 1 1/4". Remove the spade bit and replace with a 3/8" drill bit. Drill through the last 1/4" of material. Repeat for the second knob.

 

Line drawing for the construction of the angle bracket knobs.

On the inside of the head, mark-out a four spoke shape. This will provide the necessary grip for tightening the adjustment knob. This can be achieved by making a quick cardboard template to pencil in the lines of the spokes.( see sketch below ) 

 

Line drawing for transferring lines to the angle bracket knob.

 

Now that the spokes have been marked out, set-up the drill press with a 5/16" Dia. drill bit. 

 

Where the lines of the spokes intersect the handle shank, drill the 5/16" holes through the head of the knob. This will provide a clean finish to the spokes.

 

Take the knob and bandsaw down the spoke lines to remove the excess material. Clean up the band sawn surface with sand paper and radius off any sharp edges.

 

You will now have a four spoked handle.

As you can see from the photograph on the right, the knobs are complete apart from installing the       1 1/2"x 3/8"-16 socket head cap screws.

 

De-grease the heads with acetone and insert through the 9/16" hole. The socket head cap screw will have to be screwed into position as the 3/8" hole at the bottom of the handle is not quite a clearance hole. Use a 5/16" hex key to tighten the screw into place then secure with a mix of two part 5 minute epoxy resin.

 

Finished blanks for the angle bracket knob.

 

With the adjustment knobs finished you can fill the 9/16" hole with a wooden plug or leave it open just in case the socket head cap screw has to be replaced at a later date.

 

The adjustment knob can now be offered through the angle head hole and attached to the T-Slot Nut. Slide the T-Slot Nut into the center slot of the angle bracket. The total combination of angle bracket, angle head and adjustment knob is now complete.

 

For an alternative method of constructing the adjustment knob, go to Adjustment Knob2

 

One pair of complete angle brackets.

 

Copyright © 2004 - 16 Steven Austin

 

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