Pinning the Table PT3
If you're considering moving to a fixture based system for holding your work, you will need a repeatable way to mount and remount your fixtures.  Pinning your table consists of adding hardened steel pin liners to the table and steel thread inserts to secure fixtures.

A few notes on pinning:

  • Pinning your table is something you need to think long and hard about, it is a one way trip, once the liners are in they are considered permanent.
  • Properly pinned, you will retain full use of the tee slots.
  • Do Not try to just drill the holes and not use the liners and inserts, the cast iron holes will wear out in a short period of time.
  • Although we use the term 'pinning' the pins are actually used in the fixture, hence the term fixture pins.
 
After a night of the setting up, remove all the tape from the table and clean up any excess Locktite.

It is now time to lap the liners a bit to open them up.

We open up the liners a bit for a few reasons:

  • The liners have an exact .250 hole, standard dowel pins are a bit oversized, so they don't fit all that well.
  • The liners get squeezed a little when putting them in the table.
  • It's easier to expand the liner, than to reduce every pin.
   
Start by "chucking" the dowel pin and put "Fine Clover" on the pin and in the liner.

 

We use .250 hardened dowel pins.  The fixture pins we use are 1", but for chucking we use 2" pins.
   
At about 400 RPM use the manual feed to gently insert the pin into the liner.  Cycle it up and down a few times over about a 3 minute period.

If you try to go in to fast the pin will bind the liner, if you hear the motor bogging retract the pin instantly.

Do NOT let the pin bind into the liner, that will be VERY bad.
   
After a few minutes clean off the clover.
   
Clean the hole out with break clean.
   
Test fit the liner with a new pin.

Repeat the process on the liner until a new dowel pin goes in easily.

We use the lapping dowel pin (the one in the chuck) only once per liner, then flip it.  After each side is used we get a new lapping pin.
   
All liners in and lapped, all thread inserts in.

At this point we are ready to begin working on a fixture.
   
We make a little map of exactly where our pins and inserts are.  You will want to do the same.

Click on the picture for a exploded view of the picture.
   
If you'll notice we put all the liners on the edges, there is no rule against putting a row down the middle.
   
Back to Production Notes Index