low-volume, low-cost in-line lead trimmer

I am looking for a low-cost tool to uniformly cut a 44mm row of in-line pins to
an adjustable length. I don't have the budget for a fancy automatic DIP lead
trimmer, I just need something that can be used to quickly trim 10-20 custom
LCDs.

Our current solution is to use a piece of wood of the appropriate thickness as a
guide to cut the pins with a common flush cutter. Results are OK, but slow.

Can anyone suggest a solution under $500? I can imagine some kind of thin
elongated hand shear/cutter with an adjustable fence. In my imagination, such a
tool would retail for around $200. I have been unsuccessful in finding such a
device from any of the usual tool vendors, nor has google/froogle found
anything. If it matters, the two rows of pins are 30mm apart.

 

Take a look at this small shear:

< http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=90757
If you can bend the rows of pins slightly you might be able to cut a
block of aluminum as a guide and set it between the display and the
moving blade of the shear. I'd like to buy one for my shop, but can't
afford it yet.

Another solution would be a carefully machined block of aluminum the
right thickness with holes for all the pins. Slip the display in and
use a padded cover to hold it in place while you take a piece of die
knife to slice the pins off.

 

The problem is that the pins would have to be bent more than "slightly",
especially if you include the thickness of the platform the shear has to be
mounted on. I've looked at various bench-top shears, but none I've found can
accommodate the 30mm row spacing without serious bending.

I've thought about making a manual equivalent of the D-2C:
http://www.fancort.com/leadcut.htm
We have a small CNC machine, so we can make the plate(s), but I'm not sure where
to get an appropriate knife.

 

< http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=38413

Die knife is used to stamp the flaps and notches when making
cardboard boxes. It is strong and very sharp. I used up the last
pieces I had but you should be able to get a little from any corrugated
box plant that makes or repairs their own dies.

You could weld a guide on a large pair of scissors or tin snips, like
those made to get a square cut on ribbon cable. You should be able to
make it adjustable with a few springs and allen cap screws if you need a
tight tolerance.

One last suggestion. How about a Adel, or similar hand nibbler? I've
used one to trim pins on connectors. It cuts about 1/8" per nibble.
Make a sample cut and see if a multiple of the cut will come out to the
right length.

 

I'm surprised nobody has mentioned using a dremel and saw with a guide?
If your doing a very low volume, make an aluuminum or whatever guide
as was mentioned, and zip of the pins with a dremel and saw blade.

--Andy P

 

Won't that leave burrs on the cut leads?

 

It depends how tight the tolerances are. If the holes are small enough
in your block idea and the blade is close enough, burring should be kept
at a minimum, if not completely eliminated.

Another idea would be to use an "H" shaped block. If you support both
the top and bottom of the pins, and have them exposed via a groove on
the side of the block, you could slide the saw blade through the groove
(carefully...perhaps mount the dremel stationary and level, and slide
the block witht he lcd) and this will keep the final portion of the cut
on each pin from bending over and create the burrs.

Also, barring the slot idea, as long as you go slow enough to let the
saw do the cutting instead of pushing on the pins, it shouldn't burr up.