Sunday, September 16, 2012

"Tractor Time" or "Getting Lathed"

I guess the tractor thought I wasn't paying enough attention to it now that its running so well again.  I was mowing the lawn last weekend and it dropped a steering linkage.  Naturally it was the one that doesn't have removable ends.  They don't make steering linkages for these forty year old garden tractors anymore so I decided I'd make lemonaide out of the situation and build a new one myself.

Tractor Supply had set of garden tractor steering knuckles that used the same size nut as the old one so I bought those and a three foot long steel bar of about 5/8"  diameter.  The new knuckles are made to screw onto a rod so the idea was to cut the bar to the right length, put a couple of bends in it to match the bends in the old one and thread the ends to take the new knuckles.

The new knuckles screw onto a 7/16" rod with 20 threads per inch so the "building" part of the project involved turning the rod's end down to 7/16" and threading it to take the knuckle and then cutting the rod to length and turning and threading the other end for the other knuckle.

The turning is the "making lemonaide" part too.  I know next to nothing about how to use a metal lathe and will be getting on the job training.

The rod won't fit all the way through the lathe's headstock so I wound up chucking one end and running the other end in a steady rest.  The first end turned out really well:

For the second end, I decided to turn down a section where the end would be and then cut the rod and thread it.  This is one of the learning parts:

The setup is all wrong.  I should have kept the steady rest closer to the bit.  As it is, there's a lot of flex in the bar and it is making the cutting go really slow and chattery.   When it came time to eat supper and I only had this section turned down to .45" I decided to take the opportunity to kick back and rethink  what I'm doing.

The new plan is to remove the bar from the lathe and cut it to length on the band saw.  Then I'll put the finished end in the chuck.  The rod will go into the headstock at least a foot so I won't be chucking on the new threads and, with it cut to length, it should make a much more rigid setup with just a few inches of the bar sticking out of the chuck.  I was trying to avoid having to set it up in the chuck twice because all my lathe has is a 4 jaw chuck that doesn't self-center and it can sometimes be a real pain getting things centered.  I think it will work better if I do it this way.

So I learned a little about using the steady rest and maybe later this week I'll learn some more about centering stuff in the 4 jaw chuck.  By the weekend I should have a tractor again too.

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