[help] Working with bike materials

 

Hi, I'm a newbie with only moderate mechanical skills
and resources. I'm restoring a bent '05 Triumph Thruxton
and fixing up a '94 Magna V45 with a sidecar.

As usual, I need to modify some materials (rarely does
anything I have, buy or scrounge ever bolt right on
without some futzing and tweaking).

(1) I have a wraps-back-around-behind-the-signal-lights windshield
which I need to drill holes in and trim the bottom extensions
(which collide with the Magna's radiator). However I've found
windshield material to be very brittle when trying to cut it --
what's the best way to drill and saw through it? (And smooth
it afterwards, such as with a file etc?)

(2) I needed some hard-to-find headlight supports for the Thruxton
and finally found a pair of chromed muffler support brackets which
(almost) work. They're basically a long metal bar bent into an open
ring at one end which (with a slightly larger diameter) would fit
around my over-the-fork sleeves. An already existing hole
at the other end fits the headlight's mounting screws.
Near the ring there's another bend but at too large an angle.
So I need to expand the ring part and reduce the bend angle.
How do I go about this whilst leaving the chrome intact?
I may also have to drill holes through the straight parts.
Is this possible without causing the chrome to peel away?

(3) The Thruxton's gas tank has a dent as if the Jolly Green Giant
punched it. However the dent's contours are all smooth; ie no creases
or sharp bends. Some Google research found a clever gadget called
a Ding King designed to fix dents by pulling them out with a glued
suction cup. Has anyone here ever used one and is it worth trying
or am I likely to do more harm than good and would I be better
off taking it to a pro?

TIA for any help,
SQ
cc rec.motorcycles

 



Drilling, use a slow speed, sharp drill bit. Keep the material cool with a
constant flow of water.  Take your time.  A dull bit will build heat and it will
either melt the material and grab the bit, and/or it will crack.

I have sawed windshields successfully by using a die grinder with a cut-off
wheel and making several passes, cutting a little deeper every time.  Mark where
you want to cut with a magic marker.  Make the first pass with the die grinder
and just barely score the cut, just enough to mark for the next pass.  Make
another pass, cut just a little deeper.  Keep repeating until it cuts off.

If you try to cut the whole thing in one pass, it will crack.

--
Futility Man

 

Futility Man wrote:

will

where

I have successfully cut acrylic windshields using a variable speed
saber saw with a coarse blade, run at slow speed.  The coarse blade
keeps the teeth from clogging up, and the slow speed prevents the
material from melting.  No problems with cracking.  I put masking
tape on either side of the cut area to protect the shield from
being scratched by the base of the saw.

 



I tried that but the shield I was working with tried to close up the cut as I
progressed, grabbing the blade.  

--
Futility Man

 

Futility Man wrote:

That's why I used a variable speed saw, and ran it at a very slow setting.
It is counter-intuitive, but using a coarse blade, with widely offset teeth
is exactly what you need to get a nice smooth cut which doesn't close up.
A thin fine-toothed blade doesn't work well.  After making the cut with
the sabre saw, a little dressing with a file and/or a sanding block is all
I needed.

The Bosch website (I used a Bosch saber saw) has recommendations for the
proper blade for cutting acrylic sheet.  The T101A blade is specifically
recommended for Plexiglas®.  14 teeth per inch, with ground teeth & taper
ground back.

http://www.boschtools.com