Improving the Cutting Drum

After I wrote the post about the torch cutting drum I started wondering why I hand’t bothered to replace the old cut up screen with a better bar grate top as I mentioned.  I guess in a lot of situations good enough is good enough.  This was a case where it wouldn’t be worth my while to devote a lot of time or expense to upgrade.  But, I decided to at least make an inquiry.

When I made my next trip to Kan Fab, I asked about a bar grate drop and came home with a 2” x 3” piece.  I cut it to make a new cutting drum grate top and the remainder I used as a tread  leading to the concrete walk outside my east door where I have had a hard time growing grass.  I recently seeded it and put down some straw cover.  The grate would let me walk over the usually muddy area and be a nice boot scraper this winter. By spring the grass should grow up through the grate.  I didn’t expect to solve two problems at once but sometimes I get lucky.

I tested the new cutting setup and it works fine and it is an aesthetic improvement.  It’s a minor thing as things go but, more importantly, it got me thinking more about how important it is to have good support services.   That led me to write the plug for Kan Fab and describe a bit about their business.  I ask then for help with a lot of things and they deliver the goods.

http://www.persimmonforge.com/

Kan Fab, Inc.

This is my “tip of the hat” to some folks who have helped me a lot.  Kan Fab is my primary site for obtaining all the materials I need to do my forging operations.  I visit their facility several times a week to discuss pattern design, project planning, or to pick up orders.  We have collaborated on a couple of projects too.

Early on, I started making decisions about how the number of parts needed determined the cost efficiency of how they were made.  If I only needed a few pieces I could cut them out with a torch and clean up the slag and quickly get going.  If I needed 20 or 50 or more parts the cleanup time became too expensive.  I used some laser cut blanks for a while but the service wasn’t available locally so I had to add in shipping cost.  Eventually I switched to water jet cutting which was done by Kan Fab and no shipping costs were incurred.  An additional benefit was the convenience of  getting easy person to person consultation about designs.

When I first started my relationship with Kan Fab I was getting my steel stock form another source but I soon switched to them because of  the convenience and good service.  Usually I could drive there and pick what I needed from their “in-house” stock.  If the material was a bit odd I learned to place an order a few days in advance of the date I needed it.  They get the stock from their supplier and cut the pieces into approximately 10’ lengths so I can transport it I my truck.

I do some work for a chimney sweep and he requests firebacks, smoke guards, fire starters and other hearth related items with custom decorative accents.  I don’t have the big shearing and breaking equipment needed to make those things.  Kan Fab does all of that and I do whatever additional finish work is needed. It has been interesting to see how the product has been perfected over several years.

Kan Fab is also the source of the punch drops which I use in my tumbler.  After a lot of experimenting, I found that mild steel punch drops with a mass somewhere between a pea and a grape are the perfect aggregate for removing fire scale and burrs.  I have to take a bucket and a magnet out there and sort out only the mild steel drops of the size I need. It is a bit tediuous but necessicary.  So far, they haven’t charged me for them.

I’ve been wanting to make a hydraulic bender for a couple of years.  It’s probably the last piece of power equipment I’ll put in the studio.  I collected most of the hydraulic parts but never found the time to put everything together so I recently asked them to put it together for me.  They have the equipment and skill to do a better job of it.  I’m looking forward to seeing how it comes out.

I knew quite a bit about blacksmithing before I started any relationship with engineering/fabricating facilities.  As I entered into their realm it was a great educational experience.  I got acquainted with ironworkers, presses, breaks, milling machines, metal lathes, massive drill presses, and other industrial machines.

As interesting as it has been seeing how the big boys play, I’ll be content to do my small scale forging work.  I have a hard enough time wrapping my mind around my own stuff.  I don’t have the space for the really big machines.  I don’t have the knowledge to operate or maintain them and I don’t want that overhead expense.  However, someone has to do it.  In Emporia it is Kan Fab.  Good Job!

http://kanfabinc.com

The Cheese Fuller

This is a tool I acquired mostly out of curiosity and have probably never used for it intended use as a fuller but have used it to true some sheet metal hollow form pieces with the companion radius of a swage block.

The image shows a fuller with about a half inch radius on the left and a cheese fuller with a radius of about 1.5” on the right.

This is a good site for beginners to learn the names of blacksmithing tools and how they are used including this particular set tool.

http://www.metalartistforum.com/maf/index.php?/topic/5223-blacksmiths-tools-explained/

Radius Towers

Most of the time I use a cone mandrel or the anvil horn to forge a ring but sometimes the ring must have a more exact radius.  I found myself having to search the pipe drops to find the diameter piece I needed and decided to make two “radius towers” which were composed of the diameters I most often needed.

I laid them on an anvil and took and image which, I think, is self explanatory.  I didn’t measure them today but I believe the larges piece of pipe is 4” o.d. and the smallest is probably under 1”.  I can’t say how much searching time they have saved but it well exceeds the short time it took to make them.

The First Bolted Spring Dies

While doing some shop cleanup I came across some scrap parts from my initial attempt to make modular spring dies.  My idea was to make the initial dressing of the dies easier and also later repair or modification if needed.  Eventually, I discarded the initial design entirely but I did learn some things and there may yet be some cases where it might be useful.

One thing which I learned was that the spring stock 1/4” x 1” was not sturdy enough to hold up to my power hammer use.  The 1/4” dimension was OK but a 1.5” or 2” width was better.  Another inadequacy was the use of a single bolt where two bolts would have helped maintain the alignment better.  The piece of channel wasn’t long enough to prevent side-to-side wiggle either.

I might have been better to place the joint on the bottom arm of the spring loop rather than the top arm.  That would reduce the weight of the top arm and the joint would not be subject to as much movement.

Over the years there have been a lot of things I didn’t get right on the first try.  Sometimes an improvement is immediately apparent.  Sometimes I am stopped by insufficient skill or just not being able to see how to correct the problem.  I’ve gotten so used to the experience it doesn’t bother me in the least.  I lay the thing aside and expect that later a solution will come to me.  I have a lot of trust in the principle of “unconscious design” which I wrote about last summer.

Old spring die, side view

Old spring die, top view

Torch Cutting Drum

I don’t have to do a lot of torch cutting but I do a little bit fairly often.  I wanted to have a convenient setup by my primary work station where I could torch cut and not make a mess or burn my feet.  The solution was to set up a 30 gallon drum on an elevated base with a rectangular top screen which can span the drum when being used and stored inside when not in use - replaced by a pan top.  I have another piece of screen, as long as the durn is deep, to use when I need to support a longer workpiece.

If I had any bar grating on hand it would have been a better choice, but I didn’t have it.  I used some screen which has approximately 1” square openings and is made from some tool grade steel rod about 1/4” diameter.  I have cut through the rods from time to time so I put MIG tacks to hold the wires in place so I don’t lose pieces.  Numerous repairs have left it looking rather ugly.  I may look for a scrap of bar grating one of these days.

Sand Setting A Handrail

I’ve said that I don’t do architectural jobs anymore and now proceed to contradict myself.  A few weeks ago I completed a front porch handrail job.  It was made for a friend who was doing an extensive renovation of the home entrance landscape in more or less and Arts and Crafts rectilinear style.

The new front door incorporated a glass panel with an A&C rectangular grille which I used as my inspiration for the accent which would appear in the handrail jog on both sides.  I made some test pieces and sketches while waiting for the new concrete porch landing, steps and walk to be completed.  The final design involved using square hole passthroughs.  The cap rail was 1.25” square solid bar forged on the diamond to a 7/8” thickness.  The posts are 1.25” thick-wall square tube.

I worked with the concrete contractor to make sure he placed the “pop can” post pockets in the correct positions - four posts on both the north and south rail.  When the concrete was a fully set it was possible to open up the holes by tearing out the aluminum can with screwdriver and pliers.  The shop vac came in handy too.

I was able to enlist the help of a friend who runs an engineering company to help me build the railing structure.  He had a lot more experience than I in this type of work.  We took the posts to the site with a bucket of used water jet garnet abrasive sand.  As each post was set in the hole the hole was filled with the garnet sand and packed while the post was held vertical and checked with a level.

The pair of posts which incorporated the decorative infill were taken back to the shop and welded.  Then we returned to the site with the cap rail pieces and placed them and marked them for cutting.  When they were cut we held them in position and tack welded them at the site to the posts and to each other.  That made the assemblies rigid enough to return to the shop for final welding and painting.  The shop vac was used to remove the garnet sand and leave the holes clean for pouring the anchor cement.

Probably everyone who does railing knows the sand trick but it was new to me.  I had always used some kind of jig I could clamp onto but this is much simpler.  Old dog learned a new trick.

Making Blacksmithing Tools

When I first became interested in blacksmithing I collected a few tools and some catalogs and a couple of books.  When I discovered The Anvil’s Ring I registered for a meeting which was advertised.  I watched all the demonstrators and was fascinated.  Everything was new to me and everything was exciting.

In some part of a demonstration I saw Clay Spencer use a curved blade hot cut and a bit later at a break I said I had never seen one in a catalog and wondered where to get one.  He said, “Make it”  The answer was completely obvious to him yet was eye-opening to me.  After doing years of woodworking I was accustomed to buying tools but not to making them.  The aha! moment stuck in my mind as a major difference between the crafts - the blacksmith makes his tools.

It was a bit intimidating to work with tools steel at first.  I only had hand tools at that stage and tool steels were harder for me to forge.  Mostly I had spring steel and grader blade to work with because they were cheap at the scrap yard.  When I later moved to H13 and S7 they were even harder to forge but I had a power hammer by then so I could do it.

I haven’t bought a tool in quite a while.  After almost twenty years of working I usually have everything I need.  If I need something different I make it.  Even so, I really don’t consider myself a tool maker.  I reserve that title for the smiths who specialize in making really beautiful hammers and hardies and other things.  I have a couple of Hofi style hammers made by Tom Clark which I use regularly but I haven’t bought any other really pretty hammers I’ve seen at conferences.  I think I would be inclined to just put the on a shelf and look at them rather than put them to use.

Here’s another hammer I won’t  be using in the studio.  It was given to me by a friend, Jesse England, who is a very talented glass blower.  He also does blacksmithing.

More About the Butcher

Here are few more words about how I like the butcher tool to fit on the handle.  First, the current handle is not the one originally on the tool which was essentially a long skinny stick.  I bought a short claw hammer handle and did the grinding to suit my needs.

I like the fit to be tight enough that when fully seated I can’t just easily slip the head off but if I tap the top of the handle on the anvil the head comes off.  To seat the head I place it on the top end and tap the butt of the handle on the anvil and the head scoots down to the fit point.  Every use of the technique is a demonstration of Newton’s First Law of Motion.

Getting the fit right requires some extra length of the fit zone and some precision sanding.  It is a pleasure to use a tool which works exactly right.  Details make a difference.

The Butcher Set Tool

Yesterday, I was working on a small sculpture and used the only straight handled butcher I have suitable for use on the anvil.  I came across it and some other set tools early in my blacksmith experience.  I was still doing woodworking at that time but as I searched flea markets for woodworking tools I occasionally picked up blacksmith tools too.

What I remember particularly is that I noticed that some of the tools had a handle fit so loosely that the head could readily be slipped off.  At that time I didn’t understand that the loose fit was an intentional feature.  It is probably seen mostly on butchers but also on other set tools such as side sets or odd-shaped punches.  Anytime the face of the tool is asymmetrical in a way that renders it useful in either right-hand or left-hand orientation the reversibility is handy.

In my case I needed to establish a shoulder on the right side and the left side of a vertical raised area.  Ken held the workpiece steady on the anvil while I set the butcher in place and struck it about four times with a hand sledge then knocked off the butcher and turned it 180º and tapped it back onto the handle and used it on the other side.

There doesn’t  seem to be much information about set tools on the web.  The Wikipedia article could use some help from someone. http://en.wikipedia.org/wiki/Set_tool  I found one reference which explained that the butcher, straight or curved, was used to start the shoulder.  The side set had a less steeply inclined face and was used to set off more of the mass from the shoulder and the set hammer was used to square the shoulder.  It performs the same function as a flatter but has a smaller face.  I have one of those which is rectangular and another which has three straight sides and one convex side to the face.

I found one image of a handled side set here http://brisbaneblacksmithsupplies.com/anvil_tools but I would call the tool a butcher because of the steep angle of the face.  Decoding the jargon can be difficult for beginners.  Experienced smiths have largely just forgotten the parsing issues and have learned to live with the inconsistencies.

Actually, I don’t use the butchering technique much and when I do it is usually with the smithing magician.  I do have a set of dies for the fly press but have used them just a few times.  Mostly I have used the technique when making tenons.  In the smithing magician guillotine tool the butcher dies can be reversed to create “near” and “far” offsets.  I saw a drawing of a die that was a combination, “near” on one half and “far” on the other half.

Yesterday’s work required a butcher with a straight edge.  When making tenons on a square bar a curved butcher has the advantage of cutting deeper at the corners making the line easier to see when the bar is rotated for the next strike.  Once again, the terminology seems a bit confusing.  The “curved” refers to an arc relief in the cutting face rather than to a bend in the blade which would essentially make it a curved chisel or gouge.  I’ll have more to say about that soon when I show some chisels I made recently.

Two Hammer Straightening

This topic came to mind while making some long shank shoe spoons.  After fullering the blade some of the pieces had a slight offset of the blade-shank junction.  The shoulder was asymmetrical.  If the offset is not too extreme it is easily fixed by clamping the shank in the vise right at the shoulder leaving the blade extending beyond the vise jaws.  The neck-shaft junction is heated and the blade tip cooled...A heavy hammer is placed against the tip of the blade and a light hammer is used to tap the long-side shoulder until it is centered.

I first thought of this as a second class lever technique but now I’m not sure how is is properly described in mechanical engineering terms.  I do like the way it works.

Making Bolted Spring Dies

Especially in the early phases of making dies the die face may need several refinements.  I made most of my early dies it the flat bar spring design usually from 3/16” x 2” or 1/4” x 2”.  Each time I needed to redress the die face I heated the hairpin of the spring and opened up the angle until I could access the face area.  Then I had to heat the spring again and close it up and get it back into register.

I started thinking about finding a way to disassemble the die to make those adjustments easier.  That would eleminate the torch work and allow even better access to both die faces and would avoid the problem of possible misalignment.

I thought that this type construction might be less flexible that the typical hairpin, D or oxbow type of spring loops so additional flat bar length might be needed.

Looking over my available scrap I selected a 2” square tube with 1/4” wall to use as the spacer/mounting box.  I elected to cut two holes in the top so I could weld two nuts flush with the surface or slightly recessed.  That way I could put the die back in the tumbler and clean it up if I wanted and not risk thread damage.   I decided to use substantial bolts, 7/16” minimum, grade 2.  I haven’t used them enough to determine if they need to be grade 8.

I’m just starting to use these dies so I don’t have a long run experience yet.  It looks promising and by spring I’ll have made the decision of whether this will be my standard spring die construction scheme.

The images show a generic die made for my main power hammer. There are end tangs which have a loose socket fit and a central saddle which wraps around the bottom die.  The bottoms of the tangs are welded shut so, when I put a die in the tumbler, small pieces of metal aggregate don’t get stuck inside.  During use the die is relatively constrained but not tightly constrained and I believe this saves a lot of wear and tear on the hammer itself.

Nuts tacked flush with top surface.  Complete the weld and grind flush.

Assembled die.

Disassembled die.

A Cool Spring Die Design

There is not much better than having a good friend unless it is having a good friend who is smarter than you are.  Jim Friel is one of those friends.  He has retired from a long career in blacksmithing and fabricating but maintains an active interest and attends some conferences.  He lives in Colorado and I live in Kansas.  We both usually attend the BAM conference  in Missouri the first week end of May which traditionally features winter-like weather.

After the conference he sometimes hooks up his motor home at my shop and stays a couple of days to exchange blacksmithing ideas.  We enjoy the banter about which of us learns the most.  He has far more experience but I work on projects which are quite a bit different than the ones he focused on.  At any rate, we have a great fun time and I think both of us benefit from the back and forth.

Today I made some modifications to a couple of dies which he made for me on one of his visits and I felt the preliminary results would be worth sharing.  Jim observed how I was doing the process of texturing sheet and then cupping the sheet to make hollow form tree branches.  Based on his experience he showed me how what I was doing in two steps could be done in one step.

He made a couple of spring dies which could produce the product needed in two sizes.  This was a couple of years ago and I am just now getting back to the project, a personal one, which I call “The Persimmon Forge West Wall Sculpture.”  I always work with the idea of “killing al least two birds with one stone”.  In this case it meant  working with the dies Jim made but changing them from the hairpin bend spring die design to a bolted spring die design, a concept I am experimenting with.  I also have another client project which will need these dies.

I torch cut the hairpin bend and straightened the arms on the two dies I mounted them on a 2” square tube spacer and made the double bolt fixation modifications.   Then I discovered that one had an “overbite” and the other had an “underbite” misalignment.  Almost immediately I realized that the dogleg offset die design accommodated making an easy realignment adjustment possible.  The offset bends of the top leaf were deigned originally to create a “well” which could receive the up-curving edges of the workpiece. I doubt they were thought of as a mechanism to adjust the alignment of the top and bottom die faces.  However, in fact, they do just that and it works great.

Because other deadline projects interpose, I may not actually get back to my wall sculpture for a few weeks and I won’t be able to actually test these modified dies right away but I wanted to share how the adjustment was done and soon I’ll write more about the bolted spring die design.

The images are essentially self explanatory.  I clamped the “underbite” die in the vise and closed the spring with a C-clamp.  Then I heated the appropriate area of the top spring with the torch and screwed down the C-clamp until the registration was correct.  The “overbite” problem required two heats to shorten the lever arm by turning the tall right-angle off set into a more squat Z.

1 Bolted Spring Die

2 Die Underbite Misalignment

3 Clamped & Heated

4 Die properly aligned

5 Die Overbite Misalignment

6 Clamp, Heat & Bending Fork

7 Both Bends Completed

Sprinkler Spike Base

I don’t know if this will help anyone, but I take a shot at it.  Some one might add “a long one with a limb in the way.”  I didn’t get much work done in the studio today because I had to run some errands and then do some fall yard work.  Some of the yard work was watering newly seeded lawn areas.  In Kansas, it seems we have to repair some areas of our lawns in the fall every year if we want them to look good after the ravages of summer.

So, to the point.  I was watering and noticed that I have, over time, made some helpful modifications to my tools with a blacksmith orientation.  This is the sprinkler retrospective.  First, I bought a standard lawn sprinkler at a local store and set it up.  I am fortunate to have very good water pressure, but the downside is that the pressure caused the sprinkler to flip over on it’s side and spray a tunnel into the ground or up into the air.  One of my granddaughters would call this the “dead bug” position.

I countered that problem by fabricating a base attachment with four forged spikes about 6” long which I could stomp into the ground and there was no way the sprinkler could flip over.  

It seems I’m not often willing to leave well enough alone and just say “It’s good enough.”  It didn’t take long before I came up with the idea of adding the tall handle so I didn’t have to bend over to move the sprinkler.  I was already using “hairpin bend leaf’ finial type stakes in my garden, so I welded one of those onto the base.  It worked beautifully and eliminated the stooping and bending effort.  

Next came the idea of turning the hairpin bend into a horizontal loop which would be a socket to hold a twist nozzle.  Sometimes I just rely on the sprinkler to do area watering and sometimes I use the twist nozzle to do more precisely targeted watering.  This accommodated both.  I guess my brain burned out at that point since I have made no further modifications.

I have noticed another potential benefit of putting a handle on the frame.  It assures that the sprinkler cannot tip over with the spikes pointed upward which could be a deadly hazard.

This is a special which has worked well for me.  I worry about things with sharp points and use this sprinkler cautiously.  I don’t sell it or recommend it for anyone else to use.  I hope that someone will come up with the next better version - Spiked-long handled sprinkler 2.0.

The Boone-Broussard Grille

I was looking at one of the few pieces of demonstrator-made ironwork which I have collected.  I really was interested in this piece, bought it at the auction - somewhat over my budget - but have no regrets.

This grille was covered to some extent in this post.

http://persimmonforge.blogspot.com/2011/12/buying-my-little-giant.html  It was made by Mike (Smyth) Boone and Wendel Broussard at the IronFest Blacksmithing Regional Conference, Grapevine, Texas June 1-3, 2001. The conference also featured Frank Turley and Jeff Mohr.

It was terribly hot.  I spent most of my time watching Mike as his work was closer to the type of work I was doing than Wendel’s chasing and repoussé.  They both did masterful work and I really liked the finished piece and was lucky to get it at the evening auction.  The next morning Mike also gave me the concept drawing done by Robin.  I have enjoyed these things  for over 12 years now.  

I think we owe a lot to these talented artists who are willing to travel and work in difficult and unfamiliar settings to help educate the rest of us.  Hat’s off to them.

You can still find the link promoting the conference here.  http://www.oldworldanvils.com/ironfest.html

Stress Risers

I already presented some material on this subject in the post describing bandsaw blade cracks and the post of the broken round stock shear blade.

The increase in peak stress near holes, grooves, notches, sharp corners, cracks, transitions in mass or grain structure due to heat effects and other situations is called stress concentration. The agent of the concentration is called the stress riser.

Blacksmiths frequently encounter this in both design and production phases of work. A common example is seen in forging an upset square corner. It takes practice to end up with a strong radiused inside corner and not a weak folded in crack in the corner.

I encountered another example in a 10’ pocket steel tape I always carry. I’ve had two of these break over the years in the same place - at the second hole where the catch element fastens to the ruled tape element. I’m sure there are many considerations which go into the decision of why the tape is constructed in this manner and all things considered there may not be a better choice. Still, I find it interesting to ponder.

Some stress riser references:
http://en.wikipedia.org/wiki/Stress_concentration

http://www.ewp.rpi.edu/hartford/~ernesto/Su2012/EP/MaterialsforStudents/Aiello/Roark-Ch06.pdf

http://www.kokch.kts.ru/me/t1/SIA_1_Stress_Concentration.pdf

Poor Design

Here is a quick example of poor design.  It may not be intrinsically bad design, but is problematic in it’s particular environment.  I acquired some tractor seats at at scrapyard and decided to make three chairs for the studio.  I chose the scroll foot design because I knew that by tweaking the scrolls it would be easy to get all four feet touching the floor in a stable configuration.  So far, so good.

What I failed to see coming was how the scroll being open at the top it was a perfect design for snagging extension cords and other things.  As, I was still building workspaces in the studio, I did have occasion to use extension cords with some regularity, so I had opportunity to prove the design to be a nuisance.

Everything in the workspace is well settled now and I haven’t used an extension cord for quite a while.  The hoses on the torches are well away from the chairs and the shop vac gets used infrequently so the problem seems to have gone away even though I never corrected the chair feet.  Sometimes just ignoring a problem long enough can seem to work.