Making Hinged Dies

I’m always looking for another idea to experiment with.  After working out the modular bolted die scheme I started looking for a simpler way too accomplish some of the same things.

A hinge articulation seemed appealing.  The top leaf could swing open for redressing or revision.  However, it wouldn’t have any intrinsic spring action.  Gravity would close the die but something else would have to open it.

What is the function of spring in a traditional spring die anyway?   One function is to open the die enough the workpiece can be inserted and to open the die between strikes so the workpiece can change position.  The other important role is to keep the die faces aligned.

The idea of the hinge is that it serves primarily for alignment.  It doesn’t constrain alignment as precisely as the bolted design but in most cases it is close enough.

I tested two versions of the hinge barrel which is welded to the end of the top leaf.

1. The tight fit - I cut some small pipe sections about 2” in length to serve as the barrel of the hinges.  A 3/8” bolt could not be inserted but was close to fitting.  I slit the pipe longitudinally and drove in a of 3/8” round coil spring mandrel and hammered the pipe to open it slightly and the 3/8” bolt then fit perfectly.  

2. The looser fit - A quicker alternative is to use 5/16” bolts which have a slightly sloppy fit.  

The short pieces of flat bar which carry the bolt axel serve to help control the alignment so the difference in the play of the bolts in the barrels didn’t seem to make much difference in performance.

As in the bolted box die design, a box serves as the spacer.  I welded a 9” piece of 1/8” x 1/2” flat bar to the top of the box to provide the spring action.  This can easily be bent to the desired angle to achieve the best opening.

In the testing phase I was working with three old traditional spring dies which needed revision to work properly.  The top and bottom dies were salvaged and the remainder of the frames were scrapped.  It is a little tricky to get the die cavities aligned when welding everything together.  Two dies worked nicely but the third is a bit off and will need more work.  After a die tests well I'll tack weld the nut to the flat bar carrier.

At this point, I’m thinking this is going to be my preferred method of initial closed die construction.  If tighter constraint is needed it is easy to convert this design to the bolted design.

The Welded Nut Mechanism

I have mentioned several times that I like this simple technique.  It isn’t elegant craftsmanship like drilling and tapping and wouldn’t be acceptable in finished products but it is quick and effective for making jigs and other shop tools.  I use it today mostly when making dies.  

It is important that the hole through which the bold will pass is oversize so that there is no chance of obstruction and no chance the welding current will pass through the treads and create a contact point gall.  I use both the drill press and the torch to make the holes and don’t see much advantage with either one.

I like to screw the bolt in all the way and lock it in place on the opposite side of the hole with another temporary nut.  This assures the perpendicular orientation and can lock the bolt in the centered position protecting the threads.

The outside nut is secured with MIG beads.  I may just tack the nut and remove the bolt before adding more weld.  Finally, I apply anti-seize and insert the bolt again.

As, I said before, these are usually 7/16” bolts.  I’ve twisted off some smaller thread stock but not 7/16” that I recall.

Forging press die saddle with locking bolt.

Drill over-size hole.

Lock in position to weld with temporary nut.

Remove positioning nut, apply anti-seize and chase threads

More Engine Valve Chasing Tools

I wrote a little bit about making chasing tools from engine valves on August 2011

http://persimmonforge.blogspot.com/2011/08/engine-valve-tools.html

After making four larger curved chisels I decided to make a miniature set too.  

I keep an assortment of partially prepared tool blanks of various tool steel origin and can quickly select a size and shape I need.  In this case I chose envying valve stems.  I’d already cut off the flare end with a Zip disc.  I’m not sure of the alloy but think it may be EV-8 stainless steel  http://www.motor.com/article.asp?article_ID=1792

http://www.enginetech.com/rebuilder-valves.php There may be a difference in alloy between intake and exhaust valves.

At a near lemon heat this steel is still difficult to forge.  It seems to be air hardening and usually does not need any other heat treatment.  I forged the tips in four different radius swage gutters to establish the outside radius and did the finishing with grinding tools.  The cutting edge has a low angle to keep the tip strong.  For the job I have in mind (carving a die face) a shallow depth cut will be fine.

It’s about an 80/20 or higher chance the edge will be hard enough without some heat treatment.  If, after a quick test the edge is blunting, I polish it again and torch heat the 1/4” adjacent to the tip and oil quench.  That process has a nearly 100% success rate.

Making A Monkey Tool

I went through a phase where I made some grilles and gate and railing which used peened tenon joinery.  I made several monkey tools to true up the tenons and create a square shoulder for a nice fit.

I don’t remember who showed me how to make these tools but I remember he said to be careful to relieve the inner edge so there was a little radius at the takeoff point of the tenon rather than a sharp edge which may be a stress raiser.

I found one old handled monkey tool in a flea market and made all the others from jack hammer drill rod which was once abundant at my scrapyard.  I just drilled out the center hold to the sizes needed.

I remember using them once to put tenons on flat bar slats that made a table shelf.  After the round tenons were formed I flattened them into an oval and made a corresponding drift.  When assembled the slats stayed in the horizontal plane nicely because they could not rotate.

Here is one reference on how to make a monkey tool:

http://www.provos.org/index.php?/archives/65-Making-A-Monkey-Tool.html

And you can buy them:

http://www.blacksmithsupply.com/catalog.aspx?storename=blacksmith_supply&DeptID=147760&ItemID=8704197&detail=1

My Monkey tools.

In driving position.

Monkey seated.

Slight edge relief on Monkey gives the tenon base a stress relieving radius.

Nauman Sinus Punch

I came across these tools which haven’t been called for in quite a while, but when the opportunity arises they are really handy.  I learned this technique from Dan Nauman at a BAM meeting several years ago.  When I got home I made my own tools.  Three were made from coil spring and one was an Allen wrench as I recall.

The pattern I tested came from Dan’s demonstration.  The printed copy is glued to the sheet metal with rubber cement.  I had an ash log just the right height for working - about vise top height.  As soon as the tools were made I tried them out.

I have forgotten the gauge of sheet I experimented with but I think it was 16 gauge and the holes punched easily and cleanly with the slugs sinking into the end-grain surface.  I thought it was a lot faster and more fun than drilling if there were a lot of holes to make.  

The shape of the cutting edge of the punches is important as well as their sharpness.  I don’t know the upper limit of metal thickness for this technique but I’g going to guess that above 14 gauge it would be better to go to a mechanical punch or to drill.

See Dan’s work here:

http://bighornforge.wordpress.com

New Pocket Pliers

A while back I roughly forged blanks for a new pair of pocket pliers to replace the store-bought ones I have carried for years.  These were to be a bit longer, round nose like scrolling pliers and have the blacksmith look rather than the commercial mechanics look.

Last week I came across those blanks and finished them.  I think they were 5160 coil spring but it has been long enough that I have forgotten.  They are very stiff and did nor require any heat treating so another alloy is certainly possible.

They work great.  I’d say they work better for most things than the old commercial ones but the personal involvement may have prejudiced me a bit.  The images show the alignment I like in tongs - wide crotch and in-line reins as well as in-line bits.  There is some difference of opinion about those things and I’ll get to that next time, maybe.

Fly Press Leather Pad Cutter

I make a lot of botanical sculptures mostly of sizes which serve as table displays.  Invariably the heavy base has some undesirable rough areas which could damage a table top.  First, I tried some commercial soft pads with adhesive backs but later moved to making my own pads from cowhide scrap leather.  

Our local farm and ranch supply store usually has a selection of packets of leather scrap.  I look for ones which have flat pieced - preferably black and also long strips, usually dark brown which are good for suspending forged dinner bells.

I cut circles from the flat scrap and fix three pads to each sculpture using black silicone caulk as the adhesive.  I position the pads so they avoid the touchmark areas and make the piece stable.

I I could have found a nice cutter in an antique shop I probably would have picked one up.  This site shows a nice collection.  http://www.antiqbuyer.com/images/ARCHIVE_PICS/archivetools/Leather/leathercuts/leather_cutters.jpg  I think those are designed to be struck with a mallet.

Well, I wasn’t that lucky so I made three versions with similar mechanical design but which cut three different size circles and fit in my fly press.  The smallest makes about 1” circles and the largest cuts about 1.5” circles.  I used SketchUp to draw a rough version of the largest one.  

I start the construction process by cutting a piece of lawnmower blade scrap to make the blades.  A strip an inch wide and about 5” long will make the large size cutter.  I forge a circle over a round mandrel and MIG weld the seam and clean up the inside of the blade so it is smooth and won’t have burrs which tend to grab the leather drops and keep them from ejecting.

The blade edge is made by ordinary grinding, sanding and polishing.  I make a cutout in one side of the blade to allow the ejecting lever room to travel and it might be a good idea to cut another knockout access window in case a real jam occurs.

I make a barrel and axle mechanism with some small pipe and round rod.  The ejection lever tip is heated and bent and polished so the angle is optimal for pushing out the cut pads.  

The top structure begins with the 1” x 1.5” bolt which I use as my standard ram tang.  I’ll grind away the threads at the tangent where I want the locking bolt to seat after I know exactly where that will work best.

The shank is cobbled together so it is appropriately long and strong.  In this case I used a large punch drop and a short piece of 1” round and MIG welded it all together.  I usually just “tack and test” before I do the final welding.

The final piece is the bottom tool which will stop the blade travel.  I tried several materials and settled on a block of very high density polyethylene.  I wanted it to stay in register with the blade so I used the black silicone again to glue on a 7/8” nut which exactly fits the fly press base tang hole.  The poly block is rigid enough to back up the leather so a clean cut can be made in three easy bumps and prevents damage to the blade edge.  The more the system is used the better it all works. Some lubrication inside the blade may help too.

The depth is sufficient to cut three pads before ejecting but it is a little harder and probably doesn’t save time.  I should note that the images show the large cutter with the original 60d nail lever.  I later changed that to 3/8” round rod about 6” long.

There are a lot of blacksmiths around demonstrating how to draw a taper or forge and upset square corner so I tend to concentrate on sharing the odd-ball things that are part of my blacksmithing business.  These leather pads are a little detail that can keep clients happy.


I posted the drawing on 3D Warehouse.

http://sketchup.google.com/3dwarehouse/details?mid=35e6828e8afa4a3a4ee323db343c418a&prevstart=0

http://www.persimmonforge.com/