Friday 26 November 2010

tri square refurb

An old  W J Henderson Tri Square in need of re-squaring, I do like to use this square but it was not quite accurate enough to use on accurate marking out as I need it to right now.

Luckily for me, the blade had a haunched double mortice and tenon joint simply held together with four very small dowels and very minimal glue.

Easy enough to remove the dowels with a very small size m6 bolt tapped gently till the dowel started to move outwards then repeat to the rest of dowels. Next, tighten blade in a vice and with a small offcut of wood and a mallet gently tap the handle till it slides off the blade.

 Now before reassemble make sure both edges of the blade are parallel with each other with a nice sharp jack plane or bigger if you wish to shoot one edge straight, then set up a marking gauge and mark a parallel line then shoot down to this line.

Now because the square manufacturers before had only used small dowels and very little glue is one reason why it was out of square, I decided here to add wedges to add extra strength to the joint. This meant I had to chop out to allow for the wedges to grip the sides of the original tenon, as shown here.    

I had to think of the best way of getting it all square again whilst I was glueing it together so I decided to use my old Stanley site roofing square with sash cramps as shown here just gently cramped together as the glue dries.

It wasn't till I got to this stage that I realised  I had no small dowels by then too late to glue them in, I would normally do this at this stage,  but ha ho never mind, I, ll have to make some later and glue them in and allow to dry before removing cramps and then clean it all up.


Glued and waiting to dry, I leave the dowels for now till all glue is dry and set hard.  Please don,t allow these lovely old tools to be thrown away refurbish them and keep them going.