Sunday, 16 January 2011

Marking knife

I bought an Ashley Iles right-handed marking knife several years ago from  Workshop heaven but never used it, when it arrives unpacked it, handled it and decided it was too short to use and could be deeper in its depth, put it back in the wrapper and stored it away.

Well now it time to use it as  I now have a load of dovetails to cut, my old Stanley marking knife is now getting a little short in the length of its blade I only have the one a right-hander, so time to retire it.

I decided to make a handle for it as it's just a flat piece of steel to make it comfier in the hand whilst using it between the thumb and index finger so you actually had something to hold onto.  I also decided I would like a matching pair this time around a  left-hander and right-hander to mark flush with the edges of the dovetails for more accurate cutting, so an order went off yesterday for a left-hander.

I felt by adding a handle to the exiting blade I now could extend the blade cutting length giving the whole knife more length so in my design I have allowed from the front edge of the brass ferrule 60mm of a steel blade that is usable, I have not altered the depth of the steel blade that is in front of the brass ferrule at all, nor it's thickness, the only grinding done was to the remaining 68mm  of the blade that was ground down to slide and fits snugly into the internal diameter of the brass ferrule but only for the depth of the ferrule, then it's ground down to a 5mm depth for the remaining blade length.

 I am not a professional turner, in fact, I have only resent purchase a new second-hand lathe back last year, the last turning I did was back in the seventies and then only a very little, before then when I was at school some  45 years ago, so you will see from here on is from memory or I make it up as I go.

Below a dummy run a temporary handle, for now, I decided to play around with the design for a while to see if I can improve on it whilst waiting for its left-handed partner blade to turn up. This handle is just an odd offcut from an old broom handle.

Today the left-hand blade arrived, I cut off a slice of Bali from a large chuck I bought back last year.

Here is shown the dummy run on the right-hand blade plus the new left-hand blade yet to be altered along with the first attempted handle for the left-hand blade.


Showing left-hand blade ground to allow brass ferrule to slide up to the set 60mm shoulders, setting the depth of drill to 70 mm to take the remaining 70 mm of the handle, plus turned to handle ready to have the interior tang hole drilled.




Whilst the turning was successful, when it came to fitting the blade I started to have problems as shown here with the third and fourth attempt splitting the handle when they wear very nearly driven fully home, in fact, the fourth attempt split on the very last tap of the hammer, fiddlesticks, so back to the drawing board time to redesign.


Finally as seen here in the last photo, I added extra bulk directly behind the brass ferrule plus gave the handle a little extra girth and shortened the tang inside the handle down to 40mm, success. Now I have a matching pair, I am really chuffed with them, in particular, the finished burnish, just ordinary sanding and burnished with shaving. ENJOY.