Power hammer build photos
Posted 15 January 2010 - 09:15 AM
The following posts will show progressive pictures of how I went about constructing an air hammer. Changes were made from the purchased plans due to cylinder selection and materials availability. Final pictures will come over the next so many weeks/months until it is finished and tested followed by pictures of artwork utilizing the hammer.
It was last summer 2009 I was saving money to buy an Anyang 33 power hammer when life introduced some monetary constraints that prevented the purchase. It was long decided I would build my own power hammer so I started scrounging and purchasing materials. This is something I didn’t want to do. I am very fond of “off the shelf” machines backed with part libraries like what is provided by Anyang. I’m not so fond of treasure hunting in scrap piles out in back of the factory to be tortured by constructing something from junk. However, that’s how much of my equipment was obtained so I’m blessed with consistency.
Please feel free to ask questions and/or comment or criticize constructively so people may get some knowledge from your input in case they choose to undertake this task themselves. There were times when I was able to use a milling machine at work to help build certain parts and there were times I did the best I could with my drill press at home. Most of the work was done with a welder, abrasive cutoff saw, and hand grinders. David Robertson’s plans are useful for constructing an air hammer with basic tools. It does take some technical work to get things lined up and square well enough so the end result is satisfactory for good operation. The date this introduction is written, I have yet to complete the tooling, plumbing and some assembly. Pictures of the finished project will come in time as I complete it. The winter has been cold and the work on this has gone slow.
Thanks for reading. Spears
A local steel fabrication company had some 2” x 13” hot rolled bar in the yard so I selected this as the material for my anvil block and base plate. Two pieces 30” long were welded together for the base. Four pieces 24” tall were welded together for the anvil block. This gives a weight of about 710lbs for the anvil and 440 lbs for the base. With a 75lb ram, the anvil/ram weight ratio will be ~ 9.4 to1. Running my mig welder close to “wide open” I was able to “ok” penetrate the 2” thick bars enough to hold them together decently.
The spine/bushing-sleeve column assembly was flipped upside down on the cylinder bracket for welding
The spine assembly was clamped to the anvil block where it was shimmed and vertically leveled and welded. A string hanging a large washer was used to line up the cylinder attachment centered vertically level with the bushing sleeve.
The foot pedal was constructed almost totally from junk except for the ¾” valve. The radial springs were a found item. I took a guess and built the foot pedal to take 8 springs. After the 7th one was installed it seemed to spring open and “close” the valve smoothly. It may look kind of funny with these radial springs out to the side, but a blind person would tell you this operates like a dream.
A bar of 4140 2”x 2” was purchased for the dies. These dies have yet to be dressed, welded, and heat treated. The flat ones will more than likely be used the most. The four plates are bearing bronze alloy 932 and will be adjustable inside the sleeve to hold the ram that slides up and down.
Posted 15 January 2010 - 10:52 AM
what A wonderful start to you new power hammer, Thanks for posting the progress ,
Hamming away down here in New zealand
Posted 16 January 2010 - 08:35 AM
Nice post on your hammer build. That certainly looks to be a more than adequate anvil you've put together there. Just curious: did you consider the use of one of the "slippery" UHMW plastics for your guides instead of the bronze? The reason I ask is that my Bull 75 has the bronze/brass guides, but I noticed that Tom Trozaick (sp?) has switched to UHMW plastic in the new Phoenix hammers, which is what I plan on using if the guides in mine ever need replacing. Of course at the rate I have been working lately, I'll wear out from old age long before the hammer guides!!! How much air/ size compressor do you think you will need to power that baby?
Take care and looking forward to more progress posts on the hammer build,
Dave, listening to the rain on the Edge of America; One-eyed Eddie is having "Time Out" for his naughty behavior toward one of the feral cats yesterday
Posted 16 January 2010 - 02:15 PM
Hope this hammer building thread grows into something special. It will/would be great to see others approach to building these puppies. I was just thinking.....here's a lil "Story" that Chris Ray and I collab'd on many years ago. He gets ALL the credit for the incredible writing. He was an incredible metalsmith.....and WORDsmith
Specializing in: Teaching and Making
hand forged and cast works of Metal Art.
Crafted with the utmost attention to detail.
For discriminating tastes and opulent surroundings
Posted 19 January 2010 - 08:39 AM
did you consider the use of one of the "slippery" UHMW plastics for your guides instead of the bronze?
Excellent question David.
I chose bronze as it is a personal preference and this is why. The adjustment screws on the slide plates can be tightened to push the plates up against the ram. In the "squeezed" condition the ram wont slide as easy so the screws need to be backed off from "bottom out" position. When using bronze I tend to have a better feel for "bottom out" than I do for plastic which gives me a better idea of the amount of "gap"or plate/ram clearance I have adjusted in. However, both materials will work and the plastic is probably slicker. David Robertson says this air hammer can run with 10cfm. I'm going to use a 7.5 hp ~20cfm because everything I read leads me to believe these things work better with more air. Spears
Posted 27 January 2010 - 10:49 AM
The cylinder I’m choosing for my hammer is a clevis mount hydraulic cylinder. 2.5” bore with a 1.25” shaft. A lot of air cylinders I found on the market with the desired bore size had ¾” shafts. I’m going to try this hydraulic cylinder instead.
This is a product that can be ordered from Northern tool or bought from Grainger for +/- $200.00. These cylinders used in this application are both advantageous and disadvantageous.
Advantages I found to be:
1. Heavy duty with an 1.25” shaft mostly all steel construction with 1/2" ports and good seals.
2. Available with 12” stroke providing good range to stay away from “bottom out” condition with hammer having 7-8” stroke.
3. Shaft is plated for corrosion and wear resistance which is good because part of the shaft is exposed to the atmosphere when the hammer isn’t being used.
4. The cylinder if thought to be “compressing” something is supported at the “back” end which I tend to like versus front mounted.
5. Comes with an extra port at the mounting end so in this application some oil can be applied if I think my oiler isn’t doing enough of the job.
6. This is a shelf item used for equipment like fork lifts and earth moving machines easy to find, install, and very affordable. Less than $200 mail order.
Disadvantages I found to be:
1. Hard to build heavy duty support for a clevis mount cylinder having a 12” stroke mounted at the back end. Harder yet to engineer and hold the cylinder solid as clevis mounts go together loosely and the cylinder front end has no mounting ability.
2. Inside cylinder wall probably isn’t plated since it supposed to always be filled with oil which could be susceptible to corrosion over time with humidity in the air lines.
3. The thread on the shaft (should you want to make a certain type of mount) is 1 1/8-12 which the tap for this thread cost almost as much as the cylinder itself.
4. The front (portion) and back (mounting) of the cylinder are made of ductile or “nodular” iron which is a certain type of “cast” iron which some people view cast iron as inferior.
A plate was installed under the front end of the cylinder to hold the cylinder in compression up against the clevis mount at the top. Clevis mounts go together freely and having something “captured” and tightly held will make it more solid and less susceptible to fatigue.
I put air to the top and bottom ports of the cylinder. This cycled the cylinder and made the ram bottom out the piston at the upper and lower end. I could lightly hear the friction between the bronze plates and the ram. It moved fairly quickly and sounded extremely solid when it hit. Probably not the best thing for it, but if it breaks that easily, it’s no good anyway! This is a great experiment because if it works someone can learn from it. If it doesn’t work, someone will definitely learn from it!
The shaft of the cylinder I chose has a thread which is a large 1 1/8-12. Dealing with a somewhat loose clevis mount at the top end of the cylinder, I chose not to use a clevis mount for the shaft/ram connection. Large 1 1/8 fine thread nuts can be bought in a package of 10 from McMaster carr for around $10 plus shipping. Un-plated low carbon grade 2 can be welded with good results so I chose to make my connection from one of these.
The threaded shaft is screwed into the nut which is welded to the plate which bolts flat to the ram. The shaft is screwed in and bottomed out solid against this plate to make the shaft/ram connection to be one solid unit.
The shaft/ram threaded connection is held tight by an “off center” locking screw. Drilling and tapping an offset screw hole in the nut was done carefully since the tap will be side loading upon breakthrough. I was able to grind a flat on the shaft thread so as this screw is tightened, the shaft connection is rotated tighter and harder against the ram.
Installing a locking screw “dead center” on a threaded connection neither allows the male thread to go tighter or looser. Offsetting the locking screw on the correct side will actually allow/make the male shaft screw in tighter. So if there is any wear or peening inside this threaded connection, the locking screw can actually make it go tighter and tighter.
Posted 27 January 2010 - 12:27 PM
Lots to consider for my own build. I priced the pneumatics package for my build and I am up around $1200 Cdn. ( cylinder and valving )
Food for thought with what you have posted, thanks again.
Posted 10 March 2010 - 03:01 PM
Welding and hardening the main set of 4140 dies went well and was done in one afternoon. The method described here is a “limited equipment” method but does work. Consult a book like “Heat treatment, Selection and Application of tool steels by Author Bill Bryson for more proper processing.
In the simplest form, I describe the hardening process like this: 1. Get it hot. 2. Quench it. 3. Temper it.
What I did was weld a 4”X 4”X 1/2” plate of hot rolled mild steel to a 2”X 2”X 3.5” block of 4140 in first stage of the hardening process.
First I welded a small shelf to my forge stand which would hold the tacked together Die assembly face first in my gas forge. I took the last picture to show this after everything was done. This setup allowed me to gradually move the part completely into the forge over a period of time. Efforts were made not to heat this up to quickly.
Step 1. I brought the die up to ~200 deg for tack welding in my tempering oven for about 20 minutes. After tacking the block to the plate near the corners, I placed it on the shelf near the mouth of the forge. The die was moved closer into the forge mouth over 10-15 min until starting to take color. The corners of the base plate were the first to turn red. I then removed the part, clamped it to the table and welded down both long sides and quickly returned it to the shelf in front of the forge mouth. Over the next 10-15 minutes I brought the part up to red. Target temperature was 1600+ degrees. Perhaps a bit hot according perfect processing but I made sure I completed step number one.
Step 2. Seven gallons of used crankcase oil quickly welcomed the part stirring vigorously up and down round and round. Do not do this if you’re scared to breath in a little oil smoke. It’s a 6lb chunk of red hot steel and when it first hits the oil you will see a bit of fire even at immediate submersion followed by delicious bubbles of smoke!
Step 3. The parts were allowed to cool to a 4 second bare hand touch and then they were put in a small oven set at 375 deg for four hours. Step three complete. Spears.
Posted 10 March 2010 - 03:55 PM
Posted 10 March 2010 - 04:25 PM
Posted 11 March 2010 - 08:38 AM
In the case of red hot metal being squished between two cold pieces (dies). The soft red hot metal deforms against the two cold dies. There is a bit of rubbing as the hot metal is squished flatter. That little bit of rub numerous times over creates "wear" and the wear is made less by hardening. How much? Very little, but over the longer time frame the hardened part will last longer than if hadn't been done and is a matter of choice on whether to do it for "wear" in the case of forging.
More of the reason for heat treating in the case of my personal power hammer dies is for surface integrity. Resistance against deformation. If a ball end of a ball peen hammer is struck against a soft steel part, you end up with a round dent. The same thing done against a hardened steel part and the dent is less and smaller. Hence, as the red hot iron gets cooler, it becomes harder like the ball peen hammer and more capable to "dent" or deform your dies. If your dies are on the softer side, just make sure to keep your work piece red hot and the dies should last pretty good.
This document is merely the story of what one guy (me) did and what the results were should anyone undertake the same. Tests are pending.
Consult the power hammer professionals and engineers on IFORGEIRON to get the full spectrum because they are backed by decades of forging experience. I'm a metal artist with my experience coming from my own professional studies of certain trades and my opinion (applicable as it might be) is independent of those specific to the forging industry. Regards, Spears.
Posted 12 March 2010 - 08:08 PM
I hope I didn't "put you off" with my statement above. I certainly did not mean to. The more I think about it I probably did the wrong thing by letting them cool slowly in a bucket of lime. I figured that the base plate may warp less if I did that. I made another set this afternoon. A 1" wide with a round top for working copper and aluminum. This set I preheated with the torch, welded, heated to red with the torch and quenched with oil. Forgot about the tempering though. It will be interesting to see if there is a difference.
Posted 15 March 2010 - 12:41 PM
Roller valve issue:
I did have a cycling problem when I first put air into the hammer.
After consulting some pneumatic engineers, it was determined that my roller valves needed vented in the closed position to allow the main valve spool to shift accordingly. The valves I chose were capable of being setup both ways. This was a frustrating problem to solve because pneumatics is a large market and the people who deal with them use air schematics for component definition instead of drawings and sketches. It is also hard for some suppliers to cross-reference components.
I took it upon myself to CAD draw up an air schematic using symbols that the pneumatic people understand well. I forwarded this to David Robertson who will be including this in the air hammer plans. This will help the future customers who choose his plans to understand and obtain valves and components of different brands in case the certain brand names specified cannot be found. Problem solved.
Air compressor and piping:
The air compressor I’m using is a 7.5 HP 80 gallon one from Harbor freight. The motor and tank appear to be USA made and the build quality is impressive. It runs quiet enough for my hollow steel building and is preset for 140-175 psi. I may adjust the pressure setting a bit lower as time goes on since I only need 120psi for my uses. I ran air to the back of my workshop using ¾” rubber hose from Northern Tool. This hose is good quality and extremely easy to work with and plumb to NPT using barbed fittings with hose clamps available from McMaster Carr. It runs ~$73 per 50 ft and comes with ingersoll quick connects that work well or can be removed. I suspended the hose with light weight pipe brackets like what’s pictured to the left of the cut off quick connect. This hose will be easy to splice into should that need arise.
Input air and exhaust :
Air input steps down to ½” NPT starting with the regulator and oiler. These are standard Grainger items. Members of ABANA get a discount with Grainger. I’m using a tank as somewhat of a muffler and I welded some spikes on the corners of the top four outlet holes so a rag can be stretched out and hooked on for an extra oil trap. When I exhausted air directly after the oiler I found out how well it worked as the air looked and smelled oily so I assume the hammer exhaust will also be oil saturated.
The main flat dies are the only ones I have finished at this time so I tried a couple of basic things to see how the hammer works. I crushed some wood with it until I got a feel for the action. Set for a long stroke it looks to have easily 3 beats per second maybe a bit faster. The stroke can be shortened and adjusted with both the upper and lower rollers and with the rollers closer together for a short stroke I know it will go even faster. At between 110-120 psi the hammer hits hard and took down a ½” rod with no effort partial throttle. I grabbed a piece of ¼” x 2” wide and was able to step down the material in the picture. It was able to thin it out the plate with partial “bites” in the flat position. Considering I have never touched a power hammer before, this is a user friendly tool and I’m actually able to shape the metal. Soon I will perform some testing on thicker material and with different tooling and then proceed with some fine art. I can already tell I’m going to like this. Spears.
I hope I didn't "put you off" with my statement above.
Not at all, My heat treat process is a bit lengthy and compared to techniques I've seen people use, (which work very well) I tend to treat the steel a bit more fragile than it is. That is until I put it into service. Let me know how your tools work out. It would be something to see if you could actually destroy 4140.
Posted 15 March 2010 - 05:44 PM
Posted 16 March 2010 - 07:35 AM
Posted 30 March 2010 - 08:26 AM
Full radius fullering dies were used to make the four legs with the paddles that will make table “feet” when finished. These pieces were made from 1.5 x .5 thick flat bar. The paddles were taken down to 1/8” thick in one heat with ease using those dies.
The smooth point was done with the angled die slipped over the bottom flat die on ¾” bar in one heat. I was concentrating so hard on trying to make it smooth and perfect that when I realized I had only heated it once I started laughing. That was a task that used to be quite an energy burner. The “stepped” long draw down was done on the same ¾” stock using the flat dies in one heat.
The three curl candle dish is something I’ve made by hand before out of the triangle shaped piece of ¼” thick plate sitting next to it. I used the spherical dies to make this one. Like two giant ball bearings coming together the air hammer can make ¼” plate into thin textured ribbon with way less time and energy that I used to spend doing the same task by hand. Finishing the curls and dishing out the center was the only thing done by hand and the greatest thing is, I have no blisters!
This concludes my power hammer build and thanks to everyone for their questions and comments. I hope my documentation here is found useful by some in the future when it comes to them building their own power hammer. This particular hammer works well and is nicely suited for the artwork I do. It may or may not be the tool for every task but it works extremely well for something built with only a medium level of resources. Feel free to contact me if posting questions happens not to be your preference.
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