tylerdewitt

Designing a 50lb guided helve hammer.

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Great job!

Frosty once said my hammer was "a real beefeater" but yours has mine beat hands down.

Love the 1200# anvil...totally awesome.

You done well son, and I appreciate that my design was inspiring for you.

Would love to see those vids.

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Thank you arftist! Will be a while until I have some presentable videos, but I will share them here.

Still thinking about the fact that last Monday morning I had an assembly of parts, and in the afternoon after slapping on some temporary mild steel dies, I had a machine with utility. I started using it right away for paid work. Going from no-hammer to hammer was such a leap that I questioned whether I should have just bought one in the past. It made me reflect on my reasons for building at all.

Some thoughts to share for anyone considering building:

It was a huge investment of time. In my case, hundreds of hours spread over more than a year.
Materials were cheaper than purchasing and delivering a new hammer, but if your time is worth anything at all, it's not economical.

However:

I have a hammer that I can fix/maintain/improve and meets my particular set of constraints.
I picked up many new  skills and knowledge along the way: machining, moving heavy objects, mechanics, sources for materials.

In my case, I treated it as a rite of passage. Being purely a hobbyist at the time, I asked myself if I "deserved" a hammer, cost aside. I definitely could not justify purchasing a new one. I could however justify building it: if I was to be a blacksmith/metalworker, I should be able to build my own tools. So that was the motivation.  It seems to have worked out. Now that I'm selling more, not sure if I would make the same decision. I'd likely instead want to put those hours into producing things, rather than tinkering.
 

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 Good thoughts. Mine were similar. Pure economics, I spent so much time on mine I should’ve just bought one. On the other hand, I make tools, and I learned a lot about fabrication and welding from this project. Great hammer!

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Finally got around to filming the hammer in action, videos below. After building a power hammer, I became very busy making jewellery(go figure), hence the delay. Overall I'm quite pleased how it runs, although my only comparison was a few hours on a 120lb Kinyon that I believe wasn't set up correctly (strange control, underpowered air compressor)

There's some improvements I'd like to make: run it a little faster, but I believe the spring needs to be stiffer and I'm not sure I'll get around to it. 150bpm is where it likes to run.  Good speed for tooling, but could be faster for drawing out heavy stock.

A few notes regarding noise/vibration: this was primary concern as I live in the city with neighbors adjacent. Noise was not so bad(shop's in a detached brick garage, I did some soundproofing, filled all steel tubing cavities with sand). However, even with giant anvil, base plate and concrete foundation you could still feel slight impact in the ground outside the shop. Enough that I decided to put 3/4" of rubber mat under the hammer. I don't like the rubber mat, it feels bouncier, but it's necessary. That reduced it enough that you'd have to have your fingers on the ground to sense the impact, rather than through your shoes. It's amazing the lengths that are needed to reduce vibration. I should have poured more concrete.

As a benchmark, forging 1" round mild steel on flat dies:


Next two videos show drawing RR spikes. I took off the guard to see the spring. I tried to show the control response, a few single hits and softer blows. The jackshaft/flywheel definitely helps, the hammer starts fast and doesn't coast, but you can see the spring flapping around a bit after the treadle comes up.  Maybe it's just the overall stiffness, but I think the leaf configuration might also play a role, I'd like to experiment to attenuate some of those harmonics. 

It's also difficult to do a single soft blow. You can easily feather the clutch to pull the ram up slowly, however it's very sensitive at the "tipping point" and will too readily deal a hard blow instead. It's easier to first deliver one hard blow and then lighten treadle pressure to deliver series of soft blows. I suppose every hammer has it's own personality.

 

 

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Up the speed some and figure out how to get it to dwell with the tup up.  A little slow for a 100# mechanichal.  Probably an easy fix, swap out a pulley somewhere.  Good job with the mass, nice to see nothing jumping around or the camera shaking on impact.  

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looks like a good build, is there any counter weight to balance the tup? and I think you would get much better response at light blows if there was some kind of gap between the dies at full tup down. my 90lb mechanical and my 60 and 150 all had a gap of 1 to 2" between the dies when the tup was down , this allows for the spring to help feather lighter blows. my 90lb would cycyle without the ram touching the pallet and could give the lightest blows. all of my 100lb ish hammers have run from 220 hits a minute up to 320 so a lot faster.

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No counter weight currently, but I've thought about trying it to see how it changes the response. Any suggestion or past experience on best practice for implementing that on a helve hammer? The ones I've seen never seemed to require it, granted they have post clutch flywheel that provides inertia.

It might not be apparent from some of the videos, but yes I include a gap at tup down, I use a turnbuckle on the pitman arm allowing a great deal of adjustment.
I can see what you're getting at with the spring decelerate the ram for soft blows, I'm sure I could set it up like that specifically, but I was hoping for the ability to control that via the clutch. 

I definitely need to stiffen the spring pack.

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I think a counter weight on the crank  mounted at 180 degrees to the crank ofset would alter the response back through the foot pedal and smooth the whole rotation out . I would experiment with adding weight untill the rotation smoothes out. on the spring hammers I have owned there is also quite a bit of flywheel post clutch and  the counterweight is not in anyway equal to the weight of the ram. the more flywheel pre clutch and post clutch will help with fine control.

 

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Looks like there is something funky about the Pittman arm to spring connection.

Can you post a close up photo?

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Here's an old photo from earlier in the thread, I've changed the position a bit since then. It's clamped, it doesn't slide. The movement in the videos is from the spring flexing. I think it needs to be stiffer. 

spring.jpg

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