Spring pole lathe details

I’m always surprised by the number of people who are genuinely interested in my spring pole lathe.  Many of them have asked me for more detailed information about its construction and use.  So I thought that I’d take the opportunity to post some detail photographs of the lathe.  Discussion about reciprocating lathe turning techniques will continue to be the subject of frequent posts for some time to come. 

First, let me say that I learned of this design from Roy Underhill’s writing  (human powered lathes play prominently in several of Roy’s books and I encourage anyone who may be reading this to become familiar with all of his books).  I believe that he referred to it as being German in origin.  It is quite sophisticated, as spring pole lathes go, as it uses two spring poles that are completely contained within the lathe’s framework.  This makes the lathe both highly portable and amazingly stable.  My lathe differs from Roy’s in several ways.  First, it is larger; center height is 46″, swing – 20″ and capable of nearly 60″ between centers (tailstock removed and dead center positioned in the right side frame member).  Second, the lathe is fitted with a fixed treadle that can be operated at any spot along the entire length of the lathe.  Lastly, the ways are wider and deeper,  and a set of lower “stretchers” were incorporated into my design.  The stretchers may be overkill, but I wanted to insure the lathe’s rigidity and stability and that was accomplished. 

The ability to adjust the amount of tension is very, very important.  This design provides a number of ways to “tailor” spring tension and stroke length.  The spring bridle, upper and lower connecting rod position, line position and treadle adjustment all come together to optimize the lathe’s performance. 

Enough talking, let’s get to the pictures! 

The "finished product"

Getting started

Tool rest - note steel wear bar

Tool rest slide

1/2" handle nut locks dead center into "weld nut" (available from McMaster.com)

Dead center (1/2" carriage bolt) held in place by "weld-nut"

Hickory wedges hold frame together - spring poles are "jam fitted" into "head post" (note grain orientation to avoid splitting)

"Main spring" with connecting rod (1/4" HR bar) and retainer

Crossarm rides on 1/4" carriage bolt in bronze bearing - notched keep connecting rod in position selected

Toolrest locking bolt - 1" wooden screw

Treadle - 3/8" rods ride on bronze bearings that drop into slots in the feet - allows for easy removal of treadle for transport

treadle detail - from rear

treadle detail - from rear

treadle detail - from rear

Spring bridle - note relief so spring is not damaged during movement

Tailstock or poppet, if you prefer

Just a couple of other points…

MATERIAL

Frame, toolrest and tailstock – Yellow pine dimensional lumber (2×12)

Treadle – Ash and yellow pine

Springs – laminated hickory

Threaded and tapped parts – cherry, maple, apple

FINISH – 50/50 Boiled linseed oil and Pure Gum Turpentine (elemental “long oil” spar varnish)

Advertisements
Explore posts in the same categories: springpole lathe

Tags: , , , , ,

You can comment below, or link to this permanent URL from your own site.

4 Comments on “Spring pole lathe details”

  1. paleotool Says:

    Thanks for the excellent lathe photos! I am working up plans for an Underhill lathe that I have thinking about for a couple decades I think. Yours looks great.

  2. Brentpmed Says:

    Thanks so much for the detailed photos. I just finished mine using St. Roy’s plan and several of your adaptations, it works great and I am having fun with it. Your pedal and tool rest design were great design changes.

  3. Mike White Says:

    I just finished building the frame components and I’m starting on the tool rest. These photos have been a HUGE help! I do have a question: I can’t tell from the photos if the grain on the spring poles is oriented horizontally or vertically. Intuitively I want the grain to be horizontal to minimize stress but I’m not entirely sure that is correct. Any help?

    • D.B. Laney Says:

      The springpoles are much like bowstaves. The grain runs parallel to the length of the spring. I’ve had the best results when gluing a two piece blank of hickory or ash together, then working it down to diameter with a spokeshave.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


%d bloggers like this: