Planer knife jig.

Digit · 14 Feb 2009

Some time ago I asked if anybody had ever seen the Jim Kingshott planer knife sharpening jig.
Unfortunately it seemed that no one had.
This is my copy,

This is the parts...

and here the set up. (My apologies for the cluttered image.)

The black triangular piece in the first image is for pushing the knife past the grinding wheel, there are two rare earth magnets built into it to hold the knife as it is pushed passed the wheel.
The knife sits in a recess so that it can't topple over the front edge of the jig.
The two alli knobs are to adjust the knife forward.

Roy.

mikec · 17 Feb 2009

Hi Digit,

I am intrigued by your jig as its something I am thinking about making. Could you post a few more details of the materials and construction and a few photos of a planer knife in situ.

Thanks for the photos

Regards,

Mike C

Digit · 17 Feb 2009

Will do Mike but it might be a day or two as me and the wife are catching up on gardening now that the weather's a bit better.

Roy.

Digit · 17 Feb 2009

Evening Mike C!
First pic for you. I decided to do this in dribs and drabs as it's easier for me to explain that way.
Firstly, my pillar drill does not have a hollow spindle so there was no way of fitting a draw bolt to hold the wheel arbor into the quill, and as the idea of the spinning wheel dropping out was not good I had to find another way of securing the arbor into place,
The stub arbor came from Axminster and is a No 2 Morse taper, part No 340307-14 the thread in the top is 3/8 Whit, the stub is 1 inch in diameter
I machined the stub to 1/2 inch diameter as that is the size of the large washer that fits on each side of the grinding wheel on my bench grinder, I borrow the washers from that source as required.
An 8 mil thread was then drilled and tapped into the stub to hold the wheel in place.
A 3/8 whit bolt was then drilled and tapped 5 mil across the flats and the bolt head filed to enter the the quill at the point where there is a slot to eject the chuck.
In use the 5 mil screw is removed, the 3/8 Whit bolt inserted into the arbor and the assembly fitted up into the quill with a hard push. The 5 mil screw is then fitted and tightened to stop the assembly from coming adrift.
If your drill has a hollow spindle then of course a simple draw bolt will crack that easily.
Hope that all makes sense.

Digit · 3 Mar 2009

As requested, finally, a pic of the jig with a planer knife in situ...

The jig is made from one centimetre thick Paxolin, (cos I've got lots of it!)
The knife sits in a recess in the top strip of Paxolin which is adjustable back and forth by turning the two knurled knobs at the front.
The angle at which the knife meets the wheel is adjustable as I was experimenting with different angles, but frankly it was a waste of time.
The jig might just as well be made with a fixed angle.

Roy.

mikec · 16 Mar 2009

Thanks Roy,

Sorry it took me so long to pick up this thread again

That is an ingenious jig

I will see what I can put together, my metal working is a bit limited as I only have a small Unimat modelling lathe. I have a small sheet of 6mm Tufnol which could be usedplus a number of chunks of various plastics.

Many thanks for your posting.

Regards,

Mike C