Feeding a PC05 puncher with non-DEC paper strips

The PC05 puncher is made to eat DEC fan fold paper strips.

pc05 fanfold

pc05 fanfold mounted

However this fan-fold paper is quite rare now, a pack is about $50 in 2021.

So its a need to run the PC05 with regular spooled paper for tests and daily work, saving the fan-fold for special presentations.

This may lead to a temporary setup like this:

pc05punch spool outside
or a permanent change like:

pc05 punch upgrade papertape roll

We can do better!

Requirements ...

Two things are important for a good paper strip feeder:

  1. it should be easy to change the paper source between DEC fan-fold paper and spooled paper ... no permanent modifications to the PC05!
  2. the paper must run almost force-less to the puncher.

Condition 2 is not so easy to met:

First you will put the spool onto some light-running bearings. But if you guide the paper strip later around static metall rods to route it to the puncher, you have surprisingly high friction.
Thats a problem because: The puncher (and reader) move the paper by grabbing the smaller 9th "feed" hole.

pc05 lightpattern

If paper resistance is too high, the feed hole may get deformed on punch.

When later reading the paper strip the feed hole acts not just as transport, but is also sensed optically together with the data holes and makes a data clock.

So a punch with uneasy paper feed may cause misaligned feed holes, which result in unreliable reads later.

Take care of your feed holes!

A new construction

After some trial and error I found an arrangement for the existing space with minimal paper direction changes.

Its a combo of 3d printed parts (attached below) and an industrial "taper roller" ball bearing. The bearing holds the paper spool on a horicontal plate, just by its own weight. Type is 32211 with outer diameter 100mm and inner bore diameter 55mm (see attached data sheet).

pc05punch spool bearing1

The plate uses the empty space between the short PC05 case and the rack's back door.


pc05punch spool mounted1

The whole is plugged onto the PC05's rear panel sheet, and can be easily removed.

pc05punch spool mounted2


Its still not 100% perfect: due to the horicontal paper spool, the strip must kept under tension, else it curls off the plate into the guts of the rack.

And European operators may have an additional 220-110VAC transformer sitting behind PC05, which shares place with the whole spool assembly.


PapertapeSpool2a.stl -- PC05 punch feed paper plate

PapertapeSpool2b.stl -- PC05 punch feed paper plate support

PapertapeSpool2c.stl -- PC05 punch feed paper plate spool align

pc05punch-spool-tapered-roller-bearing.jpg -- Dimensions of tapered roller bearing 32211