Wednesday, October 7, 2015

Checking the Lathe Bed Ways

On my #534.0601 Dunlap early 1940's wood lathe, I had to have the bed welded (a crack just under the ways on the tailstock end).  The welder (an older gentleman, who has been doing welding for decades) took it and brazed it.  To braze it, he ground the edges, put it over a furnace and heated it up red hot, then added material.  The problem with brazing is that it has to get red hot - which causes cast iron to warp.  On getting it back a few days ago, I knew I needed to check it for flatness to ensure things would be within specs.

However, I don't have surface for checking the plane of the ways to ensure it's not warped - meaning I thought I didn't have the tools to do it.  So, I improvised.  The next best thing was sitting in a gun case.... I had one of those laser sighting tools that sits in the chamber.  I grabbed that, threw it into the drill chuck on the headstock, and slowly adjusted it until I had it spinning without any run out (I hand turned the spindle - I didn't want it too fast).

This gave me a line-of-center from the headstock through the rest of the lathe.  I tossed on the tailstock (closer to the headstock) :

I aligned the tailstock with the laser, and then adjusted the extension on the tailstock to make sure it was lined up.  It looked great.  I slid the tailstock back a little bit, and checked it again.  I repeated this process multiple times until the last 4" of the ways - and saw some drift.  There was some slight warping from the heating.  I should have used a scraper to remove the warp, but I instead used a bastard file.  It took a couple of runs at it before it brought it back in line (it was about 0.05" off).  I am now the proud owner of a completely operational 534.0601 wood lathe with the metal turning attachment.

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