Hey guys. I'm thinking of building a Kinyon air hammer a modify the design to handle a 200LB ram. Does anyone have advice on cylinder bore size? Big Blu uses a 3.25 cylinder on their 155lb hammer and John Larson of Iron Kiss uses a 4" bore cylinder for his larger hammer. Would 50lbs more make a big difference on a 4" bore or should I icrease size? Thanks a lot

Hi markh
As you are aware cylinder size increases power both for lifting and striking. The surface of the inside of the cylinder of the 3.25 Big Blu is 8.29 the surface area of a 4 inch cylinder would be 12.56 if I did my math correctly. Certainly either one will move a 200lb. ram. If you multiply the surface area by your air pressure that will tell you how much power you have to move your hammer.
The problem is how much air will the compresser give you if I were in your situation I would go with the 4 inch cylinder, but it will really use more air.

When computing air cylinder "power" remember that in one direction it will be less due to the area taken up by the operating/cylinder rod. This must be subtracted from the total area. Secondly, there is seal stiction to varying degrees, can be as high as ten percent. Never built a hammer, but used to be an equipment engineer. Now I'm just a retard home on disability. Have fun.

Stevo

Steveomiller
Go to the top of the forum page and click on user cp
click on edit profile
go to the bottom of the page, enter your location, and save.

We would like to know where in the world you are located.

Sorry my profile was incomplete, I just updated it.

What kind and size of compressor do you have to throw an air hungry beast like that??? :-) For something with a 4" displacement I would want atleast a 10-25hp two stage compressor, or better yet a rotary screw compressor 100CFM or better. This is not going to be a hammer that you can get satisfactory proformance out of a 5hp compressor from Wallyworld... A 4" cyclinder should do the job if you have enough compressor so that you are'nt constantly waiting for it to catch up... To have the best proformance you want ALOT of free air in a high CFM rating on your compressor. You will also, want to get a big pipe and industrial sized fittings, including Filter/Regulator/oiler.... I have 3/4 lines and fittings, and can still bury my Quincy Air Master light industrial 7.5hp compressor, and I only have a 2" on my 75# Bull Hammer...

Good luck you can certainly do it, a freind of mine built a 450# air hammerr, and had no trouble till he wanted to weld on the guides;-)

Just a thought. I don't know how far along you are on building your hammer. Consider inverting the cylinder like on a Phoenix or Bull. This allows the most surface area to be used to lift the cylinder. On a Big Blu the rod side of the piston lifts the ram. Piston area minus rod area equals less surface area equals less lifting power. You really don't need large surface area to send the ram down. Gravity takes care of that. I built my hammer like that and it works great. I did not have to put on any regulators to get control either. Check the pic. The hammer could use a paint job but I would rather forge than paint.