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RE: Maze building

You've got it!

Cheers

John

See <<comments>> below and at the end.

-----Original Message-----
From: Peter Harrison [mailto:Peter.Harrison@cannock.ac.uk]
Sent: Tuesday, 13 June 2000 20:32
To: micromouse@dcs.rhbnc.ac.uk
Subject: RE: Maze building


At 02:49 PM 6/13/00 +1000, you wrote:

>To summarise:  Three lengths of wall.  "Shorts" are the length of a
peg-maze
>wall, "Mediums" are a wall plus a peg - i.e. 18cm less 1mm tolerance.
>"Longs" are a wall plus two virtual pegs, i.e. 19.2 cm.  Walls are held in
>place by pins sticking downwards near the ends which slot into 3mm holes in
>the plain base.
>

Do you have the short walls locating into the virtual pegs or do they
require pins into the floor? <<All the walls use pins into the floor.>>



presumably, if they were to locate into the floor, you would need a cluster
of four holes in the floor about each peg position. There would be no hole
at the actual peg position.

<<That's right.  Also, around the perimeter they are clusters of only three
holes.  Since they are simple 3mm holes drilled with a "turned backwards"
pedestal (The lightweight tinny sort you can add to cheap electric drills)
and with the use of a template, they take no more than a couple of seconds
each to drill.

The pin separation is 155 mm in every length of wall and the 'diamond
cluster' lies on a 25mm diameter circle centred at the 'virtual post'.
There is no post hole.  This leaves a 'bare' hole in the running surface,
but few if any mice will run with wheels within 6mm of the wall - not
intentionally, anyway!

In shorts and longs, the pins are symmetrically placed.  In mediums they are
displaced by the width of the virtual post.

Short     ---------------------------------
          | O                            O |  167 mm total 
          --------------------------------- 
          6mm        155 mm              6mm

Medium    ------------------------------------
          | O                            O    |  179.5 mm total 
          ------------------------------------ 
          6mm        155 mm               18.5 mm

Long   ---------------------------------------
       |    O                            O    |  192 mm total 
       --------------------------------------- 
       18.5mm        155 mm               18.5mm



             |   |
             | 0 |
-------------+   +--------
           0 |   | 0
-------------+---+--------
               0

            |<25mm>|


(Apologies if you are using a variable pitch font to view this.)

While I think I like the variable length wall, it makes for more
complicated manufacture <<No way!!>> and, perhaps, more drilling of locating
holes.

<<
More holes, but much, much easier.  Set up a jig with the pedestal drill
mounted over the end of a wall at the right distance "in", upright wall
pushed against a back stop and an end stop, and it takes no more than three
seconds to grab and position a wall, drill it, stack it. Use 2.5 mm holes
for the walls, then when dismantling a maze the pins will stay in the walls.

You should have cut the walls "production line style" with a bench saw and a
stop, so walls in each group should be the same length. 

Drill the "short end" of a short first, turning to do both ends. CHECK THE
PIN SEPARATION!  Drill the rest of the shorts first, then the short end of
the 'mediums'.

Reset the drill to drill the long end, fine-tuning on the pin separation in
the mediums.  Finish the mediums and start on the longs.  When you 'flip'
the long, the separation should be right.  Finish them all.

Easy!!

For pins you can use cropped off nails or dowelling split pins - though
these might be a bit short.

For drilling the base, remember to lift the sheets on a few battens so that
you can easily feel when you drill right through - without leaving a pattern
on the floor!

For the base, use three sheets 3m long by 1m wide, with at least eight 3m
battens laid on the floor to form a 'bed'.

Remember to have some steps handy!  Most of our "switchback base" problems
came from trusting gravity to hold the edges level on a batten.  Instead,
prop the sheets vertically agains a wall and screw a wider batten (same
thickness) on the underside of each join, running along the join and screwed
at both sides of the join, screws no more than 20cm apart.  That gives you a
smoother 'single sheet' base.  You could even sand the join before painting.
>>



<< What's this obsession with slots???!!!>>>  "If, on the other hand, the
short walls locate into slots in the long walls,
then there seems no real advantage in terms of accuracy or reliability in
having variable wall lengths. I guess it would be a bit easier to build the
actual maze in this case though."


Pete Harrison
IT Services Manager
Cannock Chase Technical College