Shop Built Guided Knife Sharpener

Terrry wanted to build a guided knife sharpener similar to ones he had seen on the Internet.

Sketchup of Prototype

Design Ideas

Wood Selection and Milling

Assembly

Testing

 

Design Ideas

In particular he had liked the model shown in this video on youtube.

 

We decided to build a prototype out of 3/4 inch Baltic Birch plywood and yellow pine... Sketchup of main elements of the base...
...with dimensions...

base = 11 x 5 x .75

angle adjustment riser (2) =10 x 7 x .75

knife rest 6 x 5 x .75

Angle adjustment shaft...

block = 1.75 x 1.75

dowel = 1/2 x ~6.5

Sharpening device

sandpaper plates = 1 1/8 x 1 1/8 x 11 inches

guide rod = dowel 1/2 x 14 inches

Lateral guide block...

1 x 1.75 x 3.5

1/2 through hole for angle adjustment shaft

1/8 inch hole for threaded screw

Angle guide block

1 1/4 x 1 x 1 inchesS

1/2 inch through hole for sharpener guide rod

1/2 hole down to ~ 1/4 inch thickness remaining for lag bolt and washer

   
Wood Selection and Milling
Baltic Birch plywood...for the base and sides...cut out 20° angles...multiple 1/2 inch holes for dowel and guide block assembly...glued and screwed sides to the base.
Maple cutoffs were used for guide blocks...had to drill a hole through the lateral guide block...difficult to get the throw of the quill on the drill press to make a clean cut...unhappy with the first model...
Second effort...drilled the hole a little short of halfway...then flipped unit and drilled from the other direction...used rear fence and a side stop block.
The plug left in the center was cleared out with a bit and brace...
The two holes met slightly askew...reamed it out a bit...
The 1/2 inch dowel goes through the two sides and the lateral guide block...this fit needs to be snug, a friction fit...but still easy to move...removed wood in hole with a rasp...sanded the dowel...

For the sandpaper haft...we had to drill a 2 inch deep 1/2" hole in the end of an 11 inch long rectangular shaft...1 1/8 x 1 1/8.

It would not fit on the drill press...so we did it free hand...had a faulty non-square hole...tried it again with a guide block...it was still not square...

Terry and I were beginning to think that we would not get this done...he decided that we should return to the drill press...and I decided we needed to shorten our bit exposure...
We went back to drill press...lowered table to absolute max...took a shorter drill bit...FAMAG Forstner...and then placed it as high up in the collet as possible...we had clearance of about a 1/4 inch...we then used a couble of 2x4x6 blocks to square up the blank and provide some stoutness...we were able to drill a hole that we decided was square enough...will secure a metal 1/2 rod to eliminate bow effect of dowel.

Final milling was to drill stopped holes that would hold the magnets that will secure the blade to the unit.

Forstner bit, 2 1/8 inches was used...at the drill press.

The holes were drilled so that the magnets would be out proud of the edge of the board. This should make it easier to make sure that the knife edge is off the wood.
After magnets were secured with screws, the knife plate was secured to the base.
A secured knife...
Working on strategies for alignment...
The metal rod was inserted through the guide blocks in a dry run.
Testing
 

 

 

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