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 off cut of wood and a mallet gently tap the handle till it slides off the blade.

 Now before re assemble make sure both edge of the blade are parallel with each other with a nice sharp  jack plane or bigger if you wish 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 gluing 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 to 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. hc