Gas Engine Magazine

HOW I MADE A P.T.O. PULLEY FOR MY FORDSON

By Staff

2567 Hesperia Road, Bradley, California 93426.

After stripping off all the old fiber material from the spider,
I mounted it on, using the original shaft for an arbor. You have to
use the original bearing or similar spacer behind the taper lock. I
machined the OD and ID of the bosses, faced both sides of the hub
(one side has a taper), and even took a cut on the outside of hub
between spokes. This was accomplished by moving carriage out and
around the spokes and turning the chuck by hand. This was necessary
because my spider was off about 1/16′. Don’t forget to face
bosses and leave edges sharp. Cut only enough on OD of bosses to
cleanup on all four; on mine I had to cut about 1/8′ off the
bosses to do this.

Now you need some wood that won’t split. I cut an oak burl
and roughed out two pieces approximately 10′ x 10′ x 4
1/2′ with a chain saw. I chucked each in lathe (four jaw chuck)
and bored I.D. to approximately 5 1/2′. Now you can chuck them
on inside and machine O.D. to approximately 9 3/4′. Finished
diameter is 9 1/2′ x 8′. Finish facing. You now have two
half pulleys.

Now chuck on outside and turn a groove in face 1/32′ in
depth to match one side of boss end. This will locate spider in
center of pulley. Counter bore for hub one-half of thickness of hub
in depth with approximately ten thousands press fit. (Remember wood
will give.) At this time cut a diameter mark for bolt holes 8
1/2′. You can at this time taper the bore. I left mine 5
1/2′ at center for maximum strength and 7 1/2′ bore at
outside, 5 1/2′ will clear P.T.O. hub. Now do the same with
other half of pulley. Remember one side of spider hub has tapered
face. On this half omit bolt hole circle.

Now on bench, lay the spider in groove you cut in pulley, face
and mark around the bosses (they are not evenly spaced as you have
noticed). Drill holes where marked, as large as possible without
going outside of marks. The bosses are elongated. Set spider on
holes and tap lightly with a hammer. Sharp edges will cut their own
shape in wood holes. I removed spider in approximately 1/8′
increments and cleaned holes with special ground chisel. Special
care should be taken so as to avoid breaking the spider as you
remove to clean holes. When spider spokes contact pulley, mark
around same and with wood chisel cut this material out between bore
and boss holes. Leave a tight fit (again wood will give). It is not
necessary to install spider anymore.

Repeat this same procedure on other half of pulley and other
side of spider.

Now lay out 9 holes that miss bosses (why nine I don’t know;
original pulley had nine fasteners). This is a trial and error
method. Drill nine 1/4′ holes through one half of pulley.

Check and make sure boss holes are correct depth (I gave mine
1/16′ clearance). Now we are ready to press halves together. I
applied liberal amounts of wood glue to each half and lightly
tapped with a hammer to start each half on spider.

Use heavy plate on each side of pulley and press together;
caution-keep halves even while pressing. It took about 10 or 20
tons to bring the two halves into contact when glue oozed out.
Leave it in press under pressure for approximately 24 hours to let
glue dry.

Now you have 1/4′ holes in one half of pulley for pilot
holes. Drill these all the way through. Counter bore on inside face
of pulley for nuts and washers. I used 1/4′ x 8′ carriage
bolts. Install pulley on arbor shaft and machine crown on O.D. of
pulley. BEAUTIFUL JOB!

  • Published on Mar 1, 1990
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