This is my first attempt at blogging but I thought people might be interested in the approach I took.
Getting hold of consistently dimensioned timber for making boxes has always been a challenge, especially when small thicknesses are required and when the timber is hard to come by (expensive and scarce). I have seen many examples of beautiful boxes here on LJs from makers who have either made their own thickness sanders or have bought commercial equipment. For me, buying a ready made thicknesser is not an option (far too expensive) so I decided to make my own. There are many excellent examples here on LJs so I have taken ideas from many of them. Many thanks to all of those who went before.
I decided at the outset to use a 2440 X 1220 mm (8’ X 4’) sheet of exterior 12mm (½“) plywood instead of the “banana wood” available from our local DIY outlet (B&Q) for reasons of cost and the chance to avoid warping during construction. I also decided on a 380 mm (15”) bed width as I had access to some free 19 mm (¾“) ply that had a melamine laminate on both sides. Off cuts from the fitting out of van interiors. I used a friend’s table saw to rip the plywood into strips that were 90mm (3 ½”) wide and 900 mm (35”) long.
I decided to laminate 3 layers of ply using a combination of hide glue and Titebond to create the framework. It was fairly easy to create mortise and tenon joints with the 3 layers and lots of clamps. The end product is very rigid but still quite light.
I used pillow bearings to hold the 120mm (4¾”) drum made up from 19 mm (¾”) mdf discs on a 19 mm (¾”) steel shaft. The discs were glued to the shaft with a combination of epoxy and Titebond. The shaft was trued up to the infeed table using a sled with 80 grit paper attached. Sticky back Velcro was fixed to the drum and sandpaper attached to the Velcro.
I used a 1400 rpm 1.1Kw (1½ HP) electric motor which was initially left as self tensioning for the belt pulley but later was fixed down using a tensioner to reduce the vibration when in use.
The adjustment mechanism was made from 12 mm (½”) threaded rod held in a captive nut system. Can’t think of another way to describe it. The rod I used has 15 threads per inch, so one full revolution raises the table 1/15th of an inch or 67 thou or 1.67 mm in real money. The adjustment disc has 10 indentations or segments so one division is equal to 1/150 of an inch. A nylon nut holds the adjuster in position to avoid movement from vibration.
The dust collection hood includes 2½ “ rainwater piping and is connected to my dust extractor.
I fitted adjustable and lockable wheels to allow me to move it around my very cramped working space.
I reckon I spent about £250 on the build, less than half the price of a readymade job.
So far, it does what it is supposed to do which is to fine sand timber to a consistent predetermined thickness.
Just one word of caution – when adjusting the table height it should be done in very small increments, one or two divisions on my scale, to avoid blowing the sandpaper off the drum which can be a very scary experience!
Here’s the finished article. Hope that you might be inspired to make one for yourself. Any questions or comments are welcome. I didn’t use all of the plywood in this construction so I have some left for the next challenge!
-- It always looks better when it's finished!