Sunday, 16 January 2011

Marking knife

I bought a  Ashley Iles right handed  marking knife several years ago from  Workshop heaven  but never used it, when  it arrive unpacked it, handled it and decided it was too short to use and could be deeper in it's 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 it's 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 more comfy 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 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 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 it's left handed partner  blade to turn up. This handle is just an odd off cut 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 depth of drill to 70 mm to take the remaining 70 mm of handle,plus turned 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 the them in particular the finished burnish,just ordinary sanding and burnished with shaving. ENJOY.


Matthew said...

A very nicely executed modification Martin, but then I wouldn't expect anything less from a man of your considerable talent! How are you getting on with them now that you have had chance to get a feel for them?

Martin said...

Hi Matthew, WOW thank you, your comments are very much appreciated, nice to know companies like yours Work shop heaven are taking notice, the quality of the steel is excellent love the curve of the cut as well. Once I got over the splitting of the handles by beefing up the front end of the handle directly behind the brass ferules no problems with them at all. hc