I'm trying to replace a missing depth guide on a front-tine rotovator
and want to modify a 3/4" socket drive tommy bar which is the ideal
length and 18mm diameter which nicely fits the rotovator eye with the
clamp tightened. Ideally, the bar would have a 'shoe' on the end that
makes contact with the ground. A flat piece of metal say 2"x1" would
do the job. The bar is good quality chrome-vanadium. Can it be
welded, would it have to be welded to similar material and are there
any special considerations? I have access to a MIG welder, with or
without gas.

Jupiter wrote:
The bar is good quality chrome-vanadium. Can it be welded

You can get chrome-vanadium wire, but it might be easier to
use Stainless. Cool it quickly (don't dunk it in a bucket,
though!).

On Mon, 01 Aug 2005 20:51:39 +0100, Chris Bacon
wrote:

Jupiter wrote:
The bar is good quality chrome-vanadium. Can it be welded

You can get chrome-vanadium wire, but it might be easier to
use Stainless. Cool it quickly (don't dunk it in a bucket,
though!).

Thanks.

I've welded c-v to mild using "Mirrospeed" and "Vodex" and they've
stood up to tougher applications than yours. Bronze welding would be
tough enough, too.

Mr Fuxit wrote:
Bronze welding would be tough enough, too.

I assume that's brazing?

On Mon, 01 Aug 2005 21:34:29 +0100, Chris Bacon
wrote:

Bronze welding would be tough enough, too.

I assume that's brazing?

If you don't know the difference, why are you handing out weldng advice?

On Mon, 01 Aug 2005 20:29:59 +0100, Jupiter
wrote:

I'm trying to replace a missing depth guide on a front-tine rotovator
and want to modify a 3/4" socket drive tommy bar which is the ideal
length and 18mm diameter which nicely fits the rotovator eye with the
clamp tightened. Ideally, the bar would have a 'shoe' on the end that
makes contact with the ground. A flat piece of metal say 2"x1" would
Can it be welded,

Yeah, just go straight at it. Good preparation (a nice deep chamfer) is
essential and taking any chrome plate off with a grinder for an inch or
two will avoid some of the fume hazard.

Your "shoe" could be anything. Obviously a hard-wearing steel will last
better than plain mild, or you could hard-surface it with the welder.
Either will weld to your tommy bar and your standard wire should be
adequate for this level of stress.

I have access to a MIG welder, with or without gas.

As you mention gasless, I'm guessing this is a small welder. I'd
probably use the gasless wire, _especially_ if you only have CO2 as a
shield gas (a heathen practice anyway). You should turn all the dials up
to 11 before starting and see if you can get spray transfer mode
running, to encourage good penetration (CO2 will prevent this).
Bog-standard wire should be adequate, which is good as I guess that's
what you've got! The gasless wire is probably a little harder when
finished and (on a small machine) will probably give better penetration.
The best wire (given a choice) for welding "awkward" steels would be
Corofil 20/9/3, but that's a luxury you only get when running production
quantities.

You might like to pre-heat this before welding, as it's a little on the
thick side for a kitchen-sink welder. However don't bother if it's going
to make clamping awkward. Cool it down slowly afterwards though and
don't quench it (throw it in the woodstove ashes, if you have any).

If you happen to _be_ an agricultural engineer (or can scrounge from
one), then of course hard-face it properly with something like Murair
350 wire or Hardex 350 rod. This may want a gentle preheating first (not
even glowing dull).


--
Cats have nine lives, which is why they rarely post to Usenet.

In article , "Jupiter"
says...
I'm trying to replace a missing depth guide on a front-tine rotovator
and want to modify a 3/4" socket drive tommy bar which is the ideal
length and 18mm diameter which nicely fits the rotovator eye with the
clamp tightened. Ideally, the bar would have a 'shoe' on the end that
makes contact with the ground. A flat piece of metal say 2"x1" would
do the job. The bar is good quality chrome-vanadium. Can it be
welded, would it have to be welded to similar material and are there
any special considerations? I have access to a MIG welder, with or
without gas.

I'd be inclined to weld a bit of steel tube to the foot, and clamp
that to the bar.