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I Forge Iron

Building Tire Hammer


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I know this is over kill regarding Tire Hammers and having tried to get plans with no luck. The task of building one myself has grown to the point where a Tire hammer is taking shape in my small shop. As I looked through the comments some were specific yet some were not. Starting this project lead me to Metal supermarkets here in Canada these high end scrap shops deal in every thing metal so as I layed down $165 for a frame,hammer, anvil and 4140 material I felt rather good. The axle from the rear of a front wheel car was trouble. So any one trying this be carfull as to what to get. My selection from the scrap dealer did not allow me to reverse the donut rim to put a full plate in for the shaft support.
The harness for the spring, sorry I do not know the real term, was adhock from pictures seen here. The spring from my sons old mountain bike may work well. The square hammer is 2 1/4 square about 30 lbs and 15 in long. Just a start.

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I belive the pans Clay Spencer sells has 7.5# of lead as a counter weight mounted on the tire opposite where the crank plate would hook up.
This is to balance the unit when running. Yours doesnt have this yet or else it is behind the tire.

I bought a set of plans at SOFA but havent gotten around to the build yet as I dont really need another hammer.

The Spencer hammers I have watched run were very nice.
Just like a top

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I have been wondering about the topic of counter weights since I built my hammer. With only 7.5# Does the Spencer design not sit at bottom dead center at rest? If it is totally balance wouldn't it come to rest anywhere in the stroke travel? The reason I ask is I probably have 20 + pounds of weight; maybe 30 and mine still come to rest at bottom. I have been trying to add more weight but my design limits how many plates I can add. It runs ok, but as I understand what I was told that for optimum operation, it should be fully balance so less energy is wasted bringing the hammer back up to to the top. Am I misunderstanding something??

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Dodge: Balance is a hard thing to achieve. If you put enough weight on to counterbalance the ram, it will make it easier to stop the ram anywhere and easier to lift the ram, but that's just static balance. Dynamically it will be way out of balance, because the ram just goes up and down while the counterweight is going round and round. So when the counterweight is at half stroke there is nothing on the other side to balance it. Causes the machine to rock side-to-side. Same reason it's hard to balance a one-cylinder engine. You're on the right track with a compromise, add as much as you can get away with.

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yeah,
like a ton of feathers and a ton of bricks ; )
(sorry couldn't help it)

Seriously though, my spring hammer has a banana shaped piece of 1 1/4 plate bolted onto the existing cast counter weight of the crank plate. Unfortunately it's not running yet so i can't comment on performance...
Andrew O'C

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HI all.
The dies are three inch 4140. I have enough to make more as needed. So far with the base being 1 1/2 inch thick steel it moves very little when running. I told my mentor about the hammer being finnished. For a 75 year old blacksmith he moved quite fast to come over here. Because its so small on the hammer I do not expect too much. But it pounded out 3/4 steel quite nicely. My first hammer tured out well wth little tune ups.

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  • 2 weeks later...

The tire hammer is running well. Adjustments as to stroke power and stroke length can be made with the spring. Speed and impact strength is made by changing pully size. I use a 1 1/2 size for delicate work while I up to a 2 1/2 inch for harder work. The smaller pully gives me 80 beats per minute while the larger one gives 180 BPM. The pictures enclosed are the dies I started with. I used a cup style to attach them to the hammer and anvil, a set screw keeps them in place sorry about the rust it rained the whole night and the new shop is not ready yet. One pic is the linkage I am going to replace the bolts as some are too short but still worked as I was excited to get the hammer running. The pic with the double spring is just to show what I used The spring from my sons old mountain bike. Some springs come in different weights or compression sizes this one on the hammer is 750 pounds while the one not used is 850 pounds. For my first hammer it was rather exciting.

15260.attach

15261.attach

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  • 4 months later...

I figured that you cannot balance the mechanism with the hammer head attached because the crank lifts the head weight(about 50 lbs) and drops it on every revolution and therefore dynamic balance is impossible.

I did a static balance with the hammer head disconnected.
That is the yoke, toggle arms, and spring are installed along with the recommended counter balance then check to see if the wheel will rest at all locations
then add or subtract counter balance weight until it does. Its easier if you block the treadle so that the brake pad and motor are not in contact during this check.

In my case the balance was achieved at 11.25 lbs for the counter weight.
One reason for my weight increase may have been caused by some changes I made to the crank plate. With the 7.75 lbs recommended counter balance my hammer vibrated sideways as well as vertical which lead to my changes.

While running the hammer head will make the assembly vibrate up and down which is unavoidable. If the static balance is bad then you should detect some side way vibration.

Ted

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Somehow I managed to lose my last post. If it shows up forgive the duplication.

Attached is a photo of a locomotive drive wheel. The wheel has a built in counter balance which balances the weight of one end of the connecting rod and coupling. Dynamic running balance is not necessary because the piston pushes and pulls the connecting rod with the same force.

The tire hammer as well as other similar hammers( Little giant, etc.) which lifts the hammer head with a large force and releases it with a much smaller force operates with an inherent imbalance. The heavier the hammer the less the vibration would be noticed.

Ted

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Edited by twcoffey
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I got to spend some time with Big Red today, (my tire hammer) I was working with some 1" rebar, and needed to split the ends about 1-1/2" so I tried a hack and man, what a speedy way to do it. The hack came in a tool score I made about a month ago, a bunch of hammer tools in 2 buckets, so this tool already paid for itself, just a sharp piece of tool steel welded to a handle, the more I use this tire hammer, the more uses I figure out to use it for!! I love my tire hammer!!

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  • 2 weeks later...

Countryforge,
i'm completly interested in your construction,
so can i ask about the bottom spring on the hammer head...
what does it do?
i've assumed that the spring is intended for balance,
but i can't understand anything without a drawning.

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