How not to build a power hammer

[JerryCarroll]

Mark, I would leave the springs long till you see how much throw you need. If you can notice on mine I left the back part of the spring longer so I can slide the push rod pivot back and forth to change the height of hammer movement. I have turn-buckle ends at the pivots that make the distance between the dies at rest adjustable too. It took a bit of time to get the adjustments where I need them for the stock I am using but it makes a big difference when you CAN adjust things.

[Mark Parkinson]

I have rebuilt the spring pivot and the bolock to hold them keeping in mind the sugestions here. I also fabed up the hammer top guides. so far every thing seems to be moving smoothly adding some greese nipples will help.right now I am using hex head bolts to hold every thing together when the build is compleat I will sub them out and use allen head machine bolts.

[Mark Parkinson]

I have obtained a couple of speed reducers ....I think I will use one of to power the swing arm with. the reduction is 6-1, using a 1hp 1375 rmp that would give me 229rpm or beats per min that could be altered using a smaller pully on the moter end.
Is there any reason that I should not use these in this way ie: gear box distruction....does anyone know what grease and oil a gear box like this would use?
I am now musing over what method to use to transfer the power a disc with a pivot point (bolt)on it or fab up a crank arm are there any advantadges to either one? I found at Princess auto a turn buckle type device used on tractors 3 point hitch I believe? it is 3/4" and the eye ends have what looks like a self aligning bearing in them...this would allow for a little slop in the allignment Not that I will ever need that LOL

[skunkriv]

That gearbox will work just fine. Use 80/90 gear lube. There will be a plug on the side a couple inches off the bottom. Fill til it runs out there.

A disc would be more "balanced" than an arm but at 200 rpm I wouldn't worry. To be truly balanced you would need a counterweight on the disc to offset the weight of the load of the reciprocating parts. If you have something to make a disc I'd use it, if not build an arm. Mount the disc or arm as close to the gearbox as will work and cut the rest of the shaft off. Less side loading on that bearing.

You have a spare, that means the first one should last forever

[teknition]

Hi Mark,

You have that spring pivot looking much better now, nice job

May I suggest that on the hammer guide end you make a pipe sleeve for the bottom bolt like you did on top and use longer bolts with lock nuts on them so that the pipe sleeve can roll freely on the bolt to help reduce friction and wear from the spring sliding over the bolts. The more friction you engineer out of the design, the smoother and more efficiently your hammer will run.

As far as using a gear reduction box on the hammer, I really can't say if thats a good idea or not. In my mind I think it would make tuning the ideal hammer speed harder. I think most guys that build a hammer are using pulley diameters to tune the hammer and by adding the gear box into the works, you are adding in another set of ratios to the mix. On the other hand, we all learn by trying different things, so give it a go and tell us how it works

If the gear box has an oil fill and drain plug, I would think the lube would be 80/90 gear oil.

[Mark Parkinson]

Skunkriv & Tek thanks for your input on the gear oil I'll have to pick some up monday...I just spent a couple of hours striping down and clean the one box I am really surprised by the lack of wear in a gear box that was built in 1958 (date on the spec tag) the grease on the trust bearings had dried out but a wash in the parts tank showed no wear on the bearings and I repacked them with a moly grease and everything is traveling smooth. I believe I will go with the crank arm as my lathe only has 8.25" over the bed, a great lathe for the small screw cutting jobs etc. I do but I really don't want to over burden it.cutting back the extra shafting makes a lot of sense, the uneven load will be bad enough with out adding extra leverage.....cold out in the shop today the remnants of the gear oil in the case moved like mud it took 2 or 3 minutes for it to spread out when scraped from the box....back to starting the wood stove in the morning again

[rusty_iron]

Gday Mark,
Found a few things on the net that might be of use to you.

A set of plans for a rusty type hammer like yours, that may help.
FERRUM - Daniel Gentile - Mechanical Power Hammer Plans

And from the same guy, I found a discussion on Don Fogg's forum, that may interest you. If you do a search on power hammers on this site you will find a few pages other than this one.
Building a power hammer - Bladesmith's Forum Board

Now I have not built a power hammer as yet, but plan too, so first let me say thanks for the great pics and discussion. I was thinking about your disk or crank question. Is using a heavier disk like a flywheel appropriate here?

Thank again,
Regards
Rusty_iron

[Mark Parkinson]

Rusty_iron..thanks for your input...I do have a set of the Krusty plans and they are helpfull but like all plans for power hammers are missing some critical measurements...on the flywheel I had thought about it...but you want a power hammer to stop when you take your foot off the bar, a flywheels momentum could lead to extra strokes ...The extra weight would be great to even out the balance problem that a crank motion imparts to a shaft, but impractical in this instance without the addition of a brake on the flywheel...yet something else to think about

Mark

[ApprenticeMan]

Originally Posted by Mark Parkinson

Rusty_iron..thanks for your input...I do have a set of the Krusty plans and they are helpfull but like all plans for power hammers are missing some critical measurements...on the flywheel I had thought about it...but you want a power hammer to stop when you take your foot off the bar, a flywheels momentum could lead to extra strokes ...The extra weight would be great to even out the balance problem that a crank motion imparts to a shaft, but impractical in this instance without the addition of a brake on the flywheel...yet something else to think about

Mark

Mark, a VERY EASY and simple solution to the problem of extra strokes, and the way the ram will drop down when no power is being applied, is to use a light spring on the upper arm, to hold it in the UP position, and for the brake, you can add one of these to the drive shaft, in between the pillow bearings:


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