Strippit Machine Dowel Pins

Strippit Machines,  as well as many other Machine Tools,

have many Complex and Precision Mechanical Components that are Precisely Located During the Building Process at the Factory.

Shot-Pin Housings,  Turret-Bases,  Bearing Mounts,  Die Bases,  Etc.,  are all Located,  Bolted-Down,  and Finally Dowel-Pinned using Precision Reamers and Precision-Ground Dowel-Pins during the Machine Building process.

Many think that Dowel Pins are for Additional  "Holding"  Power,

but this is Not Their Purpose.

Dowel Pins are for Locating Position.

The Idea is,  when you take a Dowel Pinned Component off the Machine for some Repair,  you can then Bolt-It Back in the Original Precise Factory Position with the use of the Locating Dowel Pins.

  Most of the Time,  if a Machine Component is Dowel-Pinned,  Leave it Alone!!!

But on Occasion,  something like a Die Base will need to be removed for Repair or Alignment.    And so,  I get requests on How to Remove these Pins.

Cleverly,  Strippit uses  "Pull-Dowels",  which have a Threaded-Hole in one end.

When Originally Installed,  the Solid-End is inserted into it's Hole,  Leaving the Threaded-End Exposed,  which you can use with a Dowel-Puller to remove it.

I have several Different Dowel Pullers that I use,  depending on the Space and Location I am working in.     But,  here is information on the Puller I use the Most,

so you can Duplicate it for your own use.

Note,  If there is Not Enough Information here for You to Figure-Out how to make your   

          own Dowel Puller,  Maybe You Should Not Be Pulling Out Dowel Pins!

This is a Snap-On Tool Co. Slide-Hammer that I bought Years ago.    It is Basically a

3/4" Hardened Fine-Threaded-Rod 20 Inches Long,  and has a 4 Pound Slide-Hammer.

I had 5 Tips made in a Machine Shop to Hold Different-Size Socket-Head Cap Screws

(S.H.C.S.)  to fit the Different-Size Dowel Pins and their Internal Threaded-Ends.

These Tips are  2" Long,  and are Drilled & Tapped about  1 3/4" Deep to Fit the Rod.   Then the other end is Clearance-Drilled for the Different-Sizes of  S.H.C. Screws used.

The 5 Sizes I have are;

.187"   for a   #8      S.H.C.S.

.219"   for a   #10    S.H.C.S.

.281"   for a   1/4"   S.H.C.S.

.328"   for a   5/16" S.H.C.S.

.390"   for a   3/8"   S.H.C.S.

Use is Quite Simple.

1 -- You select the Proper S.H.C.S. and Tip for the Dowel to be Removed.

2 -- Using a long Allen Wrench,  Push the S.H.C.S.  through the Tip,

      and Screw it in as Far as you can into the Dowel Pin.

3 -- Then Screw the Slide-Hammer Rod into the Tip.

4 --  Make sure the Slide-Hammer is Straight,  then Carefully,  Slap the Hammer against

       the Rod-Stop,  and Pull the Dowel out.      Try Not to Hit Your Hand.

       It may take several Hard-Hits,  Depending on the Size and Tightness of Dowel Pin.  

       Do Not Hit Hammer Harder than Necessary,  as you can Break the Smaller 1/4"

       Dowel Pins,  as well as the S.H.C. Screws.

       Throw Away S.H.C.S. after a Couple of uses,  as they can Fatigue and Break!

5 --  When you Reassemble the Machine Components,  Clean & Flat-File Both Machine

      Surfaces to Remove the Burrs around the Dowel Holes and Bolt Holes.

We can Supply Dowel Pins that Strippit used in Building their Machines.

Common Dowel Sizes that Strippit used,  and the Drill & Reamer Sizes used;

Dowel Size            Strippit #            Pull-Hole          Drill Size                 Reamer Size

.250" x 1.0"           18204-000            #8-32                15/64"    .2344"         .2480"

.375" x 1.0"           12412-000            #10-32              23/64"    .3594"         .3740"

.375" x 1.5"           12557-000            #10-32              23/64"    .3594"         .3740"

.406" x 1.5"           104399-100          #10-32              25/64"    .3906"         .4050"

.500" x 1.5"           12589-000             1/4-20              31/64"    .4844"         .4990"

.515" x 1.5"           104399-200           1/4-20              1/2"        .5000"         .5140"

.531" x 1.5"           104399-300           1/4-20              33/64"    .5156"         .5290"

.625" x 1.5"           14802-000             1/4-20              39/64"    .6094"         .6225"

.750" x 3.0"           13578-000             5/16-18            47/64"    .7344"         .7458"

Doweling can be Difficult.    At the Factory,  a Portable Mag-Base Drill is used to provide the Rigidity & Drill Point Pressure Required to Drill & Ream Steel Properly.

But,  its still very easy to end up with a Oversize hole and a  "Loose Dowel".

So if you had a Loose  .500" Dowel,  you would simply Re-Ream the Loose  .500" Hole with the .5140" Reamer,  and fit a .515" Dowel,  or even move up to a  .531" Dowel.

That's why Strippit Makes Oversize  .406" Dowels for the  .375" Dowel,  and the  .515" and  .531" Oversize Dowels for the Base  .500" Dowel Size,  to Fix these Mistakes.

This page was last updated: May 27, 2008