Pinning the Table PT1
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.
 
Start by deciding where you want to have the liners.

Use a steel rule aligned with the Y axis to help you decide.

You will want to avoid tee slots, and have them generally centered in the lands (spots between slots).
   
Because you will want to "see" how it looks BEFORE you begin machining, chuck up a marker and mark the table.

Clean the table with a break cleaner type product so the marks are clear.
   
A simple spot will do.

We don't write huge programs to make the spots, simply use the MDI and use a G00 Xnn Ynn command.  Once there just touch off the marker with the quill.
   
Spot mark all the potential holes.

We run a big fixture, so we run our pins on the outside edge of the table.  You can put them in the middle of the table just as easily.
   
Just so you can get a full idea you should run a line at X0 and Xmax.
   
Once you are ABSOLUTELY sure that you are happy with the layout, drill the holes.

 We use a very short bit.  If you are using normal length bits, you will want to spot drill the holes first.
   
Ream the holes.
   
Clean the holes with a break cleaner type product.
   
We use drill guide inserts instead of actual jig inserts, we prefer them.

Note there is a front and a back to the insert.

Drill guide inserts are available from KBCTools.com

We use .250 ID inserts.
   
We fashioned a insertion tool that holds the insert and sets it about 0.025" below the surface.

Put the tool in the quill.
   
A liberal coating of Locktite red.
   
Press in the insert, using the manual feed quill.
   
Pressed in.
   
Whole table done.
   
Once you complete an insert cover it with tape until the next day.
   
 Continue to the next part Pinning the Table pt2