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Hardy Hole Dimensions vs Correct Square Bar Stock


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Good morning Alan and all of the great members here!!

 

My newbie question today has to do with making hardy tools and determining the correct size of square bar for my hardy hole.

 

My hardy hole is 1 inch and I recently built a bending jig using 7/8ths square bar. I'm pretty happy with the way it came out for the most part, but it feels like a little bit of a loose fit in the hole. The question is: What is the correct size square bar for a 1 inch hardy hole? Wouldn't 1 inch square bar be to thick, or would it? I tried to find 15/16ths but couldn't. (Please don't laugh if that last statement is ridiculous. LOL!!)

 

Thanks so much for your time and advice!!

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Vintage anvil hardy holes, are not going to be exact. The few hardy tools I have are fabricated from 1in angle iron that has been shaved down to slip into the hardy hole in all directions. They don't jump around while I use them, nor do they get wedged in. 

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3 hours ago, Jerry Smith said:

What is the correct size square bar for a 1 inch hardy hole?

something ever so slightly smaller, say 0.990"-0.995"? 

Basically it needs to be as big as you can so that it just slides into the hole.  

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2 hours ago, Gerald Boggs said:

Couldn't you just forge the 1 inch bar to fit?

 

This is the traditional way to do it.  For tools like cutoff hardies and such that rely on a larger section above the anvil, you either start with larger stock and forge a shank that fits the hole, upset a bulb in the middle of a bar that fits and forge it into the hole, or weld a collar on a bar that fits. For your bending jig, try 1" square.  If it fits, great!  If it doesn't, forge it down until it does.  

 

Smithing is all about making the tools to make the objects, and with hardy tools Daniel W. is correct: On older ( and many newer!) anvils, the hole will not be a standard dimension, nor will it be a uniform square.  The tools that I made to fit my Refflinghaus with a nominal 1" hardy hole (actually 26 mm) will either not fit or will bind in the Hay-Budden at my local guild shop.  An inch is 25.4mm, and that 0.6mm oversize is enough to make the difference in one dimension on that H-B.  It fits fine the other way.  Likewise, 1" square bar rattles a bit in the Refflinghaus.  

 

I have a Columbian with a nominal 7/8" hardy hole, and the tools that fit it can be shimmed to fit the Refflinghaus with Daniel's angle iron trick.  

 

I was all about precision and machining until I was in the middle of my first smithing class.  We were making tongs, and one guy was having trouble with the boss behind the jaw of his not being flat after he punched the rivet holes and set the rivet.  He was asking if he should drill out the rivet and mill the faces flat.  The instructor looked at him with an amused grin, heated it up, and smacked it hard with the rivet in the pritchel hole. Instant fit!  He said "We're smiths.  We fix stuff by hitting it." :)

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I prefer a solid shank for heavy use tool like the hot-cut and bottom tools... one piece tooling.

 

But for jigs and devices that just need to stay in place, I use 1" angle iron for the shank. Easy to weld on. If it's a little tight you just have two edges to file down.

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You can find a lot of different ways around things, takes some out of the norm thinking.  I've also seen 1in square tubing that was collapsed on the flats for hardy shanks which is a little better than an angle iron because you can get a little more weld surface on it.  Fabricated hot cut hardies, they do work but are not as durable. It's very tempting to make one out of a leaf spring by welding it to a piece of plate. Depending on your welder, your welding skill, and the plate steel your welding to, probably not the best idea.  I have seen it done and used them, but the plate their usually welded to seems to deform quickly.  Also for those who build them, I don't trust just one pass of weld on either side of them.  If forging down 1in square is a little tough, you can cut a tang out of 1/2 material and fold it over to make your hardy shank as well. 

 

Also as a saftey precaution, NEVER leave your hot cut hardy or any tall hardy in the hardy hole after using it.  It's a sure way to break or cut off fingers.  Personally I prefer my hardy under my tong hand, something about having my horn under my hammer hand works better for me.  I leave my hardy shanks pretty long so I can push it from the bottom of my hardy hole with the hammer to pop it up a few inches and then grab it with tongs (as it will be hot) before the next operation.  It's very tempting to go directly from the hot cut hardy to the anvil face to straighten out the end of your stock.  Just try not to do it, it's better to loose that heat and do it on the next than risk a finger or other injury.

 

As being new to the forge and anvil.  I highly suggest to pick up on some reading material their just as important as your tooling.  The angle iron tip I got from Mark Aspery's books, I found his books as piratical partners to my anvil.  Alan also had a PDF about tool making from a locomotive shop that I found as an easy read packed with tons of piratical information.

Edited by Daniel W
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Thanks so much Dan!! 

 

Those are some great tips!! Like you, I also prefer my hardy under my tong hand and my horn under my hammer hand! I will definitely heed that excellent advice!! (and I've heard that before too.)

 

Just out of curiosity, might you still have that PDF from Alan??  :D

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http://bamsite.org/books/Forge_Work.pdf

 

There's a of of good stuff there, collected by the Blacksmith Association of Missouri, or BAM: http://bamsite.org/books/books.html

 

The Ilgen book I first linked is one of the few with a chapter on power hammer tooling, as well as general tool making.  It is a text from a technical high school in 1912.  I highly recommend it!  And the Aspery books.  

 

I keep the horn to the left as is traditional for right-handed smiths, because it makes a more natural posture and stance when bending stock over the horn since the anvil isn't in the way of your tong hand.  Of course, my anvil is German and the hardy hole is on the left. :lol:  I worked on a London pattern anvil with rear-mounted hardy hole on the right for half my time as a smith, and I still remove the hardy tooling immediately after use.  It's just a good habit to have.

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Think I just found my reading material for the next 10 months there Alan. :blink: what a great link!

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Thanks so much Alan for the awesome PDF and for all of your great advice!! Thanks also to Dan and all of the smiths who have given me such valuable input!! 

 

I had a thought last night while contemplating forging down my 1 inch square bar to fit my 1 inch hardy hole. (Please forgive me if this question is dumb!!) 

 

Rather than having to forge down the square bar to fit every time I make hardy tools, wouldn't it be better to slightly increase the size of the hole? And if so, how would one go about accomplishing that objective?

 

Again, sorry if this is a silly question!

 

:-)

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I would think long and hard before modifying my anvil.  It was made that way for a reason, and it's easy (comparatively) to remove metal, it's much harder to put it back.  You said that 1 inch was too tight and 7/8 was loose.  A little loose is fine for most things in a hardy hole, but too tight can be a disaster.  I suspect that many of the anvils that we see with the heels broken off are the result of someone hammering on a tool with a wedged shank.

If 1 inch is too tight, take an angle grinder and grind 2 adjacent faces of a 1 inch bar so that you get a nice slip fit. 

 

Hardy tools don't need to be made one piece, it's perfectly acceptable to weld a shank onto a tool head.   Many  of my  hardy tools have a shank made from a piece of angle iron, welded to the tool.  

 

Geoff

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3 hours ago, Daniel W said:

Think I just found my reading material for the next 10 months there Alan. :blink: what a great link!

The BAM site is a great resource, but get Mark Aspery's books.  Even just the first one, will take you a long way into the skills of the Blacksmith.  Connect with your local group, a lot of them have copies to check out.

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