| There
is no magic bullet when it comes to making parts for 1/8” scale equipment.
Accuracy, consistency, and speed is what we all strive for. Aggravation,
do-overs and scrap is what we don’t want. Below are some tools and techniques’
that I use. |
| 1. Since my locomotives are
electrical, there is always a need to drill a hole for switches, buttons and
wires. One problem is drilling holes in plastic boxes. Large drills seem to want
to catch and shatter the plastic. I have found that using a step drill and a
battery operated hand drill at slow speed will give a very nice hole. The
step drill also works very well in sheet metal. It is best to have the metal
clamped down and the drill in a milling machine if possible. |
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click any image to enlarge |
2. The next tip is layout tools. Before you cut
out your parts, you need to lay them out. My favorite tools are: dial calipers,
dividers, automatic center punch and layout die (left). There are other layout
tools; however I will discuss the use of just these. In laying out sheet metal
sometimes you will encounter an odd size. One example is laying out equal hole
spacing. Having a number that doesn’t fall on your ruler can be a problem.
Having a caliper can give you any number you need to .001 inch. If you want to
scribe bend lines on several identical parts. Transfer the measurements from the
print to the material with your calipers (top right).
Clean the material, spray on some layout die. Wait until it dries. Set your
caliper scribe a short line. Saving the points on your caliper, set your
dividers to match the basic line. Now you can use the dividers to scribe
multiple pieces to the same dimension (bottom right). |
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Next is the automatic center punch (right). This
is a punch that has a spring and triggering mechanism in inside. It enables you
to put a punch mark in an exact location just using one hand. No hammer needed.
Just locate the point and press the punch toward the material. Bang, it will put
a center punch mark on the material. |
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3. Getting a consistent bend from your
sheet metal brake can be a problem. For example, you need to bend a right angle
on a piece of 18 gauge steel about 15 inches long. Sometimes one end may be a 90
degrees and the other end turns out to be 80 degrees. I bend most of my material
at the left hand end of the brake. To help solve this problem, clamp a piece of
18 gauge material about 4” long (or a piece the same thickness you are bending)
in the opposite end from the end you are using to bend the part. This will help
give a uniform clamp force to the brake. 4. Bending several identical pieces
in the brake and locating them exactly the same can sometimes be a problem. One
way to solve this is to use a thinner piece of material than the material you
are bending for a back stop gauge. The thinner material will not interfere with
clamping your part. |
| 5. Adjusting the brake for material:
This is an important step and one that is mainly ignored. Everyone is always in
a hurry. Just slap the material in and bend it. In doing this you cannot only
bend your material but also bend the brake. The nose of the bending fingers need
to be back from the bending edge of the movable leaf at least the thickness of
the material being bent. On most brakes this amounts to adjusting the distance
front to back and the clamping force.
You can see from the photo that I have adjusted the brake so many times that
finally I just welded an allen wrench to the adjusting bolt to save time looking
for the allen wrench every time I needed it. Next is to adjust the clamping
force. This is also an easy adjustment. Adjust with enough force to hold the
material but not enough to bend the fingers or the back bone. Make sure both
ends are adjusted to approximately the same clamping force. |
click any image to enlarge
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| Next consideration is the leaf or
bending bar. For thin material you can get by with the ¼” bar. Thin is .035 inch
or thinner for steel. Steel .045 to .062 you will need to make the bar ½” wide.
Steel .062 to .100, you will need to add to the bar to make it at least 1” wide
Thicker material should not be used on the standard brake 18 gauge brake. My
brake, what I call standard, is an Enco 48” 18 gauge box and pan brake.
Modifications don’t seem to be a problem with this machine. The machine looks
well used but still works great after 20 years. |
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6. One of my handy inventions is the work table
for my milling machine. How often do you wish you could put a piece of sheet
metal in the milling machine but didn’t have any way to hold it. This table is
made from a piece of 7/8” particle board I found in the scrap pile. I screwed
and glued a piece of oak to the bottom and cut out some different shaped slots
in the top. It works great. Cutting into it with a drill or milling cutter is no
problem. Having the holes cut in the top lets me put “C” clamps in various
positions to hold the material down. A great took for making cab windows. |
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7. Making grab irons can be a problem. I normally
use 3/32 aluminum welding rod for my material. My personal preference as I think
1/8” looks too big regardless of the scale measurements. Smushing the ends for
the holes are hard to do consistently without a die of some kind. I use my arbor
press for this operation.
I have mounted a piece of steel the same thickness as I want the ends to be
smashed to on the press. The steel will not flatten as easy as the aluminum. A
couple hits with the press and the aluminum is flat to your liking. To control
the depth I put a slot in my control piece to move it in and out. A simple block
with a hole back from the edge the width of the grab irons will ensure they are
all bent the same |
click any image to enlarge |
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8. Last year I needed a set of rollers and a
vertical press for a job I was doing. I ended up with a three in one machine
that can roll, bend and shear. The machine is from Enco which seemed to be a
better quality machine than the same machine from Harbor Freight and cheaper.
Plus they delivered it right to my door (left). One can just about forget the
shear part unless you are doing paper. Maybe some adjustment would help. I have
a floor shear so this is not that important. The rollers are great. I have made
a few parts on them using some 18 gauge material up to about 24 inches wide. It
takes a few trips through but does the job. |
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The vertical press is the main reason I purchased
the machine. It is 100 percent easier on my bad back and much more accurate than
the box and pan brake. The main problem is bending small parts. The back gauge
is about 2” away at it’s closest setting. I solved that by machining a piece of
aluminum and clamping it on with small C clamps. You will have to make one for
each job but they work like a charm (upper right, left and right). |
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The next problem was that the bending die is too
wide for small work. I made a smaller die and welded on some guides. I just set
it on top of the original die. I did have to cut one of the fingers down to make
this die work. However, one can adjust the die bar up and down about an inch. By
making your new die shorter one may not have to make one of the fingers shorter.
The way I do it is faster because it requires no adjustment. I have other dies
that I made for 60 degree zigzag screen and one for louvers. (left) 9. Flapper
disc for hand grinder. No matter how careful I was at grinding it seemed that I
always ended up with a divot or several divots in my work. Small as they were,
they would always show up in the paint. One day I tried a flapper disc. I was
amazed how well they worked (right). They would remove material but would
not grind a divot. I found them good for removing Rust and dirt. Mainly I use
them for grinding plug welds. They don’t last as long as a wheel but does a
better job. There is always a trade off. |
click any image to enlarge |
| 10. Self cleaning work bench. (tongue
in cheek ) Yes using your freezer for a work bench is a great Idea. Every time
that I leave a project or parts on the freezer, I can come back and the top is
clean again. Just like magic. (Photo 7) Some times the parts are on a chair,
sometimes, the parts are on the floor, sometimes I just have to keep looking.
There must be an alarm that goes off in my wife’s head when a train part touches
the top of that freezer. Sometimes a pain but it is self -cleaning. |
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| In conclusion: Most new jobs require
some sort of fixturing or new tool. Don’t be afraid to try different things. If
you come up with some great idea let me know. |
