Spencer Inline Vs Swing-arm

[kubiack]

 

I’d like to hear a little discussion about the merits of both of these hammers. The swing-arm type I’m referring to is the one with the adjustable height head. I’m going to build one sometime in the future so I have been pondering on this a bit lately but would like to hear from any one who has used either or both.

Most of the builds I remember in the last few years have been for the inline type with the explanation that you do not have to make any adjustment to the hammer to when you switch out tooling. However I have talked to two professionals who said the very much prefer the swing-arm type. The reason begin that they hit faster and harder and so they can get more work done in the same amount of time. If I recall correctly the linkage in the inline design is less efficient in converting movement of the treadle into movement of head and thus take more time and energy to accelerate the head than the swing-arm design. Also the return stroke on the inline is longer which adds to the cycle time of a blow. One think to bear in mind is that a professional usually runs items in batches and will build their processes and tooling accordingly. Therefore the cycle time of the hammer becomes the limiting factor. A hobbyist will normally be making a one off item and using what ever tooling is at hand so adjustments to the hammer may become the limiting factor.

I have used both types, but only for a short time each, and my experiences matches the above. It seemed that the inline felt heavy was hard to get moving and would wear you out if you had to use it a lot. Where as the swing-arm hammer was much snappier and just required less energy to use. To me the only time the inline is of a real advantage is when you using tall tooling such as a punch or drift and you needed to switch the blow from the tool to the stock mid heat and can not afford the time to adjust the hammer.

If any one has experience with either hammer or both and would like to comment please do so.

 

Edited March 18, 2015 by kubiack

[Frosty]

Efficiency is ore a matter of friction. A swing arm only has a limited area of friction where a guided inline has the swing arms and the guides so loses a LOT more energy to friction.

In my opinion the main benefit of inline hammers is being able to use top and bottom dies at the same time.

Frosty The Lucky.

[patrick]

Also, there are some in line designs that are very compact which is nice for small shops.

[JNewman]

I have to agree with Frosty about the only benefit of the inline hammer is being able to use top and bottom dies. 

I built and used a swing arm hammer in my shop.  I have only used an inline at Touchstone years ago doing a couple of courses. (not a Spencer inline I believe it was a Big Lick)  The swing arm hit much harder and was much snappier.   What I mostly used the treadle hammer for was chiseling and top tool work.   The hammer I made was the Jere Kirpatrick hammer  and it did not even have an adjustable treadle.  I did not really miss the adjustablility.   A hammer is MUCH simpler to build without it.    If you have a nice large top "die" (just flat no dies or insert tooling) (mine were 6"x6" )  You have adjustability in where you place the work on the bottom.  If I get more room in my shop and build a new treadle hammer it will be a simple swing arm with longer arms which will also reduce the amount of horizontal movement.  

 

[Alan Evans]

You don't get energy for free. I always reckoned I could draw metal out faster with a cross pein hand hammer than I could with a fuller under the foot hammer. Standing on one leg is tiring and not good for your back apart from anything else.

For me, the great advantage of foot powered hammers is that you have both hands free to manipulate the workpiece and any tooling required. Great for fire welding. and chiselling, chasing, centre punching and etc. Better for sensitivity and "feel" than a power hammer or hydraulic press. Mine just has a standard sledge hammer handle bolted to a spindle. Many of the chain and nail makers ones were dedicated to one process and as they required fast light blows had short shafts not much longer than hand hammers. Some of the chain makers ones had interchangeable heads. One I have seen was a "swage on a stick"and it forged the chain link weld directly into a round instead of faceting it. The anvil in that case was a bick or horn pointing straight out at the smith which had a compound half round groove which aligned with the hammer head swage and formed the bottom half of the swage form.

I have only ever made and or used "Oliver" "Tommy" or (I presume by your description) swing arm hammers. Mine has a hardy hole so I can use any of my anvil tools or power hammer spring and top tools with it. For any serious squashing though I have power hammers, fly and hydraulic presses.

Alan

[Pat Roy]

I have a Spencer design swing arm treadle hammer that is adjustable to raise and lower the head and also accomodates interchangeable dies top and bottom. I once thought about building an inline treadle but then this good deal came along. Frosty take note.

[kubiack]

As far as using top dies in a swing arm I have used a guillotine tool in a treadle hammer. While not quite as versatile as mounting them in the ram I think it would cover most of my needs.

[clang]

I built a somewhat oversized TH immediately after i saw George Dixon demo it in San Luis Obispo ('89?)

...Got all excited. Started tossing related junk in a pile the same evening after i got home.

I really had only seen one TH and didn't know what i was doing.

I've modified it a lot over the years but am  still using it almost daily. The build is pretty rude.

It's a swing arm type using truck leaf spring arms and has about 90# of falling weight and is quite tall.

If i need a shorter stroke, there's sockets to take an inserted coil spring.

I built it to be vertically adjustable, but have never moved that part.

Initially, i used the full length of the top leaf springs of a 2 1/2 ton , 48 Chevy.

It laid down a good, sharp, flat blow, but was slow and the side slop was prohibitive.

Had to cut them down.

The anvil top  and hammer head was a built up mass of layered 1" plates, 6X9" , and welded heavily.  Same size hardy hole as my anvil. I later replaced original I beam anvil stem with a solid welded mass of used scraper blades also 6 X 9". Burned up a whole lot of WW2 , funky arc rod!

More anvil mass helped! Also built a little quench tank behind the anvil with a lid that lifts as the hammer rises and covers the tank when the hammer falls to avoid splashing. There's a rebound spring at the top of the stroke.

I use it a lot. The arc of the swing arms, long as they are, is a xxxx nuisance and causes a certain amount of smearing the work.

At the same time, i took an old gas saver and worked out the pedal, pop-up torch as a necessary adjunct.. A number of folks have made their own variation of it since i demoed it for the CBA spring conf.    Don't know of any earlier.

I've also demoed a couple of times on John Mcllellan"s in line treadle hammer s.   He sells both the hammers and kits.  John@mclellanblacksmithing.com) . When properly adjusted and lubed the friction is minimal, the pedal is easy, and the blow is strong and precise...Good sensitivity. Nice design, and i like that the springs are contained in the back column. The springs on mine are kinda scary ( safety cable not withstanding).

The strength of blow and effort requirements are comparable , given the falling weight and anvil mass difference.  When i get tired of rebuilding mine, i'm gonna order one.

 

[Alan Evans]

I built a somewhat oversized TH immediately after i saw George Dixon demo it in San Luis Obispo ('89?)

 

I was a demonstrator at the ABANA conference in San Lis Obispo in 1992. I remember the year because when I walked in to lunch 300 hairy blacksmiths surprised me by singing "Happy Birthday to you" to me. Then they shouted "Speech, Speech" and gobsmacked as I was I managed to say "Thank you. This has been the best 40th birthday I have ever had!"

I am glad we both have good things to remember about the event!

Do you have any photos of your hammer?

And what is the quench tank for, dipping punches and drifts?

Alan

P.S. This is my little foot hammer. Which would have been better shown in my earlier post above. Better late than never. 

It is so simple that it can be built in hours and you can be working with it.

The nuances between the different geometries are relatively slight. If you are trying to get the maximum blow for your fabrication labour, with a view to forging with it rather than giving you hands-free advantages, I think you would do better to build a tyre hammer and let the power company provide the energy.

 

Edited July 26, 2015 by Alan Evans
Added photos

[matto]

Alan do you have any plans or drawing of how you made your hammer I like it a lot.  I have always liked the look and feel of the Oliver's. 

[Alan Evans]

No drawings but you should be able to get an idea of sizes from the standard full length sledge hammer handle and if you carefully project any element onto the drawing board behind it there are some verticals from a gate which will be around / just over 100mm (4") centres.

The spindle is around Ø35mm (Ø1/ 5/16") and runs in two plummer block bearings.

There is a keyed sleeve on the shaft with a bit of flat welded to it that the sledge handle is clamped on by two motor car exhaust "U" clamps. The "U" clamps are set diagonally in order to grip the sides of the sledge handle and prevent it rotating.

The belts are old car seat belts and bolt to the pulley. the two springs are attached to the back belt and hook onto a pin which is behind the pivot point of the foot pedal…this is a cunning plan to have a dynamically reduced spring load at the start of the down swing!

The anvil is only a bit of 12mm (1/2") plate with a hardy hole formed by a piece of box section. Very light construction but I never try to use it for heavy work, just the sensitive hands-free facility.

It is largely made up from shafting bits I found at the scrap yard and odds and sods of RSJs and RSCs I managed to collect. You are better adapting the idea to the materials you have to hand or can scrounge rather than following the exact construction of course.

I will try and remember to measure the basic geometry for you when I am in the forge tomorrow. 

 

 

Edited July 26, 2015 by Alan Evans

[matto]

Perfect thanks!!

[Alan Evans]

I even remembered to take the dimensions... 

Alan

[matto]

Thanks again!!  I will post pics when I get mine build.  

[clang]

I was a demonstrator at the ABANA conference in San Lis Obispo in 1992. I remember the year because when I walked in to lunch 300 hairy blacksmiths surprised me by singing "Happy Birthday to you" to me. Then they shouted "Speech, Speech" and gobsmacked as I was I managed to say "Thank you. This has been the best 40th birthday I have ever had!"

I am glad we both have good things to remember about the event!

Do you have any photos of your hammer?

And what is the quench tank for, dipping punches and drifts?

Alan

P.S. This is my little foot hammer. Which would have been better shown in my earlier post above. Better late than never. 

It is so simple that it can be built in hours and you can be working with it.

The nuances between the different geometries are relatively slight. If you are trying to get the maximum blow for your fabrication labour, with a view to forging with it rather than giving you hands-free advantages, I think you would do better to build a tyre hammer and let the power company provide the energy.

 

I vaguely remember that tribute Alan..A lot of grinning and even a modicum of reverence, (for the very hairy,) as i recall.

That conference and the CBA conference there the year before hand , changed my little world!  I'd no idea blacksmith associations even existed!

I'd been self taught and pretty much working in isolation for more than 20 years before that....never had seen anyone work who knew what they were doing.

I drove home with my jaw hanging open and my mind whirling and clanging with ideas and solutions.

My shop is impossibly cluttered and taking a decent pic of the TH has proved to be difficult...sorry.

Yes, the little quench tank with the linked lid is mostly for punches, shaped chisels, chasing tools etc. My collection of such is pretty extensive and i've sunk a silly amount of time into making them over the years.

They allow me to brag that after all these years i can now reliably make metal look like used chewing gum..

Alan, that's a very cute Tommy hammer!