Monday, April 26, 2010

Homemade Anvil - RR Anvil - Part 2

Part 1 talked about a home made RR-anvil which I designed, and had built with a lot of assistance from some of the guys in one of the workshops at work.

As mentioned in part 1, the issue is to stop the ringing by thickening up the web, and helping transfer any forces from the table to the base.

In an article in one of the 1920-ish shop notes from Popular Mechanics the article talked about making anvils from I-beam and thickening the web by bolting a piece of wood on each side of the web... based on that idea I made a number of pieces of 1 1/2" reinforcing steel which fitted between the rail head and the base plate of the rail.

I then cut another set of pieces which would sit between the underside of the table, and the base.

The next step was to cover the reo-bar. I used some scrap 4mm galv sheet I had kicking around. It welds easy enough, and is thick enough to stand some abuse.

The pritchel hole at the back of the anvil needed to be protected from whatever I did, so I cut up a piece of pipe to make a hollow in the back of the anvil so the underside of the hole would always be accessible.

The sheet metal shroud covered all the reinforcing bar sections welded in underneath the head, and table. Since the rail is made of high carbon Japanese steel, and my welding capabilities didn't seem to like that too much, I ensured mechanical locking whenever possible to make everything sit properly. Knowing that this would not suffice in the long run, knowing the welds made to the rail would crack under repeated hammer strikes, the next step was to fill the gaps so the reo-bar would not move under any circumstance.

The shroud was completed, with just a simple plate (about the size of a credit card) left unwelded at the back.

I obtained from the local tyre place a few bucketfuls of lead tyre weights, and melted them down using a wok burner, and one of my furnace crucibles. I could have used the furnace, but was concerned that over heating the lead might create fumes. I used the furnace when I was melting aluminium, brass and bronze since there wasn't significant issues with fumes... I was not as familiar with lead (I'm not a fishing guy who makes sinkers), so did not know how the fumes went with excessive heating. The wok burner was slower, but I figured there'd be less in the way of fumes.

Using the foundry robot, I picked up a 7L crucible of molten lead, and poured it into the gap between the shroud, and the internals of the RR-Anvil, effectively filling the gap. All surplus molten lead was poured into one of the ingot trays I use when pigging aluminium.

The lead was allowed to cool, and the final plate was recessed into the lead, and welded in place, effectively sealing in the lead. A test with the hammer and it was sweet - no ringing at all.

Here is a photo of the painted up anvil showing the recess under the pritchel hole...

And a side view of the painted anvil...

Yes, the final weight now exceeds it's original weight by more than 100%. The anvil started at 26Kg (57 lbs), and now weighs over 55 Kg (121 lbs).
The slots cut in the base web are for securing the anvil down on a wooden base, and the wonderful "imperial plum" purple paint is one of my garage sale paints I use to paint up things that need protection. I've left the top faces unpainted since it's unlikely the paint would survive the use of the horn, cutting table, and main table.

Now the anvil is finished, I've already found it too small. I've used it for a number of small jobs and for those purposes, it's fine. But once I start pointing bladeware, or other items longer than 8" at it, the table is too small. I've considered welding a larger table on top, using the existing table as a weldment anchor. I have some 2" plate here which could be used, but I'd be back at the workshops to have it cut and welded on the big machines.... I only have one small piece and I can't afford to replace it if it's spotted by a boss.

For now I limit my work in size, and am on the hunt for a decent size anvil. I'm playing with a "false table" idea to allow larger work, but that's had to take the back seat for other projects lately. The "false table" is effectively an extension of the "third hand" concept used by some smiths... a set of light gauge supports are used to retain, or hold the work on the anvil, but they aren't actually part of the anvil. All striking would still occur on the anvil, but the false table would permit me to ensure the work was level, and flat when it is on the table... still in Mk2 testing....

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