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Hardy hole size?


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I have a Henry Wright 137# anvil.  I got a couple 1" hardy tools for it and was surprised that they didn't fit.  On closer examination and careful measurement I find out in stead of 1" or a little larger this hole is actually .975".  Now I have measured this on the surface of the anvil where there is a lot of wear and tear but I have come up with the exact same measurement on the bottom of the heal also.  Yes my new to me hardy's will just take a very little fitting to make them work but I was wondering what other folks hardy holes measure and if my is standard or .025" under standard. 

 

Just curious and I have the grinder to make it work but  was just wondering.

Thanks for your help.

 

Lisa

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If the anvil was drifted with a 1" drift, instead of on slightly larger it would cool to less than 1". Even with cast anvils, were the core srunk in manufacture.
Just lightly grind or file the shank to fit in all fore positions.
Read the blue prints, hoffi has a great explination on drifts, I forget, but he said steal expands something like 1/10000" per degree. So that's something like a 1.o18" drift to make a 1" hole at room temp.

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Great point Charles and that is exactly what it looks like. It was drifted with a true 1.0" drift and in the cooling it shrunk down to this .975". But if this was a standard way to manufacture I would think the folks that make the "one inch" hardy tool would make it to .970". As I pointed out, it's not a big deal to make it fit but I was just curious that is was .025" undersize and if all hardy's, except the 7/8" holes were the same.

Lisa

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Hardy holes seem to be a bit off in most cases and close enough just isn't sometimes. Mine are close to 0.75" so some bottom tools fit the Soderfors and others the Trenton, a few don't fit either but the vise works fine.

 

How to modify tools to fit is a good question and here's my reasoning. If all a person is going to use are a couple bottom tools, hot and cold hardy and maybe a butcher then make the bottom tools fit the anvil.

 

If on the other hand a person ends up like I have with bunches of bottom tools. That's easier to do than a person might think, they can be Sooooo handy. Hardies and a butcher of course, then there are those oh so handy fullers, you start out with one or two and the number grows, oh and swages are a must. Then you discover how dandy a half penny scroll starter is and you end up with a couple sizes and styles and on it goes till you have racks, shelves and buckets full.

 

In that case, call it "normal" blacksmith mode it's a LOT easier to take a file to the hardy hole than trim even a dozen bottom tool shanks.

 

Of course that's just my opinion I could be wrong.

 

Frosty The Lucky.

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Old hardy holes are often out of square as well as out of dimensional spec  Besides heat shrinkage there was also tool wear, biased striking etc  combined with there is NOT a standard size for hardy holes; I have anvils with 7/8", 1",  1 3/8" and 3 at 1.5" hardy holes.  If I was making tools I would go for a standard number like 1" and let people dress them to fit their anvils;  sourcing undersized stock would drive the price up considerably!

 

In the 1800's blacksmiths worked to the tolerance of a worn shilling, (from a compaint on early steam engine cylinders),  your hardy hole is well within that!

 

And you had a typo there it's heel not heal.  Since you are being precise....

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