From the Workshop

December 27, 2009

Window to my workshop -34

 T21 Transitional Plane – Bushing


There are 2 single bushes and 1 pair in this plane.  The bun and the rear handle have one each and a small pair for the adjuster.  Following are a few illustrations to give you an idea of how they are made – once fitted they are invisible though vital.

 53 T21 transitional dovetailed jointer bush

The purpose of these bushes is that they spread the load into a greater contact area.  I use a coarse thread on these which is cut on to both the male metal portion and the female wooden counterpart. These bushes are permanently cemented into position with an epoxy resin.   


51 T21 transitional dovetailed jointer bush

It is possible to break the bond on the metal parts.  When the bushes are cemented in position they are less likely to rotate due to the mechanical properties of the flats you will have noticed in the photographs (in the above photo I am about to cut the flats on to the stud for the front bun, not one of the bushes – but the principle is the same).   However, as during the fixing process the epoxy resin is forced in the fibrous texture of the wood providing an additional mechanical key these will not break down.


48 T21 transitional dovetailed jointer bush

 This preparation shows a starting chamfer for thread cutting. 


49 T21 transitional dovetailed jointer bush

A die button producing the required outer thread.


50 T21 transitional dovetailed jointer bush

These are the smaller adjuster bushes.  Once they have had their flats machined on then they can be split into two.


52 T21 transitional dovetailed jointer bush

The last job is to drill and tap the inner thread. These bushes include an inner thread for the actual fixing of the intended components.  This is so they can be removed and refitted many times without degrading its strength.  To my mind this is much better engineering practice, without any compromise. 

 54 T21 transitional dovetailed jointer bush

Bushes for the rear handle.  These flats are pitched at 120 deg, which gives you three flats.  Also notice that the bushes have a lead in for the internal fixing thread.


55 T21 transitional dovetailed jointer bush

Bushes for the adjuster


56 T21 transitional dovetailed jointer bush

Prior to drilling and tapping you see here that each handle is fitted individually as the fixing bore is drilled from the top to the bottom.  By the time the drill reaches the bottom it could wander a small amount; usually no more than 8 thou.  


58 T21 transitional dovetailed jointer bush

The bush threads being cut into the plane body.  This is done immediately after boring whilst I am able to pick up the centre and maintaining a perpendicular threaded bore.


59 T21 transitional dovetailed jointer bush

When removing the work piece from the mill it is necessary to pick the threads up by hand with a bottom cutting tap, as the original has been cut with a taper tap.


57 T21 transitional dovetailed jointer bush

The final fitting/cementing of a handle bush using a one way driver.

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  1. Again, I’m impress with your workman ship! I can’t wait to see that T21 Finished. Do you have an idea of the price you will sale this plane for? And what size it will come in!
    You can email me with the info, it would be appreciated!
    Thank you.

    Comment by David Gendron — December 27, 2009 @ 7:34 pm

  2. Hi David

    Have e-mailed you separately. This T21 is 21″ long, the series will be numbered by the plane’s length, T for transitional.


    Comment by admin — December 28, 2009 @ 10:06 am

  3. Fabulous string of material, Karl!

    The mystery is solved for those of us from woodnet who pondered the spiders. I (and I’m sure others) have been giddy waiting to see the progress on the transitionals.

    They look excellent thus far.

    Comment by David Weaver — December 30, 2009 @ 10:03 pm

  4. Hi

    Thanks for your comments, hopefully will get the rest of the blog done this weekend.


    Comment by admin — December 31, 2009 @ 1:52 pm

  5. Great blog posting, very good information. waiting for your next post..

    Comment by Cheap Tools Deals — March 13, 2010 @ 7:01 am

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