Steve Bedair's
9 x 20 Lathe Site
Longview , Texas
      6 -2002

Indexable Turning Tools
How to build your own

The building pics below show attaching 1/4" TCMT carbide inserts to 1/2 tools.
This method will work for a range of different sizes.

      First the insert is laid out on the 1/2" square steel                  A protractor and a metal scribe to make marks.
      I make most of my tool holders 4" long.
      Be sure to position the insert as shown. You do not
      want the tip to hang over the edge of the steel.
      This supports the carbide cutting tip.

             Using the Mini Mill I mill the recess for the insert.                                      Milling completed
             If you don't have a mill you could use a lathe with a
             milling attachment.

        Slightly file the top edge of the 1/2" steel as shown           Using a metal scribe while pressing the insert firmly against
        to allow for the bevel of the insert. You don't have to       the edge of my workbench I mark the center hole location.
        remove much metal and it does not have to match
        the bevel exactly.

The blue represents the scribe mark. I use a center punch to mark the screw hole location.
If you look closely you will notice the punch mark is slightly toward the filed edge of the  tool.
     This ensures that the insert fits tight against the back filed edge of the tool holder.

I have already drilled a # 43 hole to allow for the 4-40 tap.
 I next use a 17/64" and drill approx 1/16" deep. This prevents
any pulled threads from interfering with the insert.

     Before tapping I also drill from the bottom of the tool holder        I used 4-40 allenhead screws to attach the inserts to
     approx half way using the larger 7/64" drill bit. You do not          the 1/2" tools. I had to cut bevels on the screws as
     want to cut threads the full thickness of the 1/2" tool. You           shown below.
     will never make it the full thickness with such a small tap.
     Tap slow and use lots of oil. ( I broke my first tap )
                      Click here for a detailed picture

         Using my 9 x 20 lathe I beveled the 4-40 allenhead screws.
     Go slow and easy.

         4-40 allenhead screw before and after bevel is cut           Attach the insert and scribe the sides of the insert.

                 Shows where metal will need to be removed.              Using a 1/4" inserts on a 1/2" tool I also scribed  a
                                                                                                 line to remove metal from the right side of the tool

             Using an end mill I removed metal to the scribe mark.            Using a fine grit grinding wheel remove excess metal.
                                                                                                        Keep the tool quenched regularly and you will be able
                                                                                                        to see the scribe mark.

                    Grinding the edges is complete                         I also milled an angle on the bottom side of the tool
             Be careful not to remove too much material
             from the tip. You want the carbide cutting tip
             to be supported.

                                                                                Completed tool !!

        I have posted this information to help provide an alternative for building less expensive lathe turning tools.
I am not saying this is the best way to do it , it's just the way I did it.

Materials Needed Building Indexable
Lathe Turning Tools
9 x 20 Project Page 9 x 20 Home Home

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This information is provided for personal use only
I cannot be responsible for any $$ this may save.
 Copyright 2002 Steve Bedair