Søren Hammer Posted December 19, 2018 Share Posted December 19, 2018 I bought this old thing for 150 USD and intend on bringing it back to life. It's a 1913 patent Jens Christoffersen helve/spring hammer, made in Copenhagen. The guy I bought it from gave it's twin to a museum. I would love any advice I can have before I begin working on it. I'm trying to make sure I go about this the right way. I usually have no problem getting things done, but having very little experience in this craft, it's always a daunting task. Everything is there, but the drive belt is broken and worn, so it will need replacing (I'm considering making my own out of leather for the fun of it, but it would work better if I just bought a modern belt - I imagine a belt snapping isn't a pleasant experience). Recommendations on what kind of belt to get would be nice. I found a UK online store that sells 3ply canvas belts treated with rubber. They are sold by the meter (6GBP per meter) and have a service to vulcanize the belt together for a closed loop (about 45GBP). it would be cheap for me to make my own out of leather since I have a lot of leather left over from a leather business I used to run. I'd just need to buy the staples to connect the pieces. I need to find a motor for it, and I'm not sure what kind of motor I need to drive this (RPM, horsepower, etc.). Recommendations on this are very welcome. From what I've been able to gather I'll want at least a 1hp motor, but otherwise I've not been able to find any solid info this - This is the thing where I feel the most clueless and would likely end up just going by trial and error to find the proper motor for this. As you can maybe tell by looking at the images, the hammer has an idler system. The belt sits on the idler wheel until a pedal is stepped on, moving the fork and belt (I assume the belt threads in between those horizontal bars) unto the drive wheel, engaging the drive system. I'll want to replace the fork with a pulley/idler wheel to not wear out the belt, since that fork seems like a really poor setup. Recommendations on how to go about this are welcome. I have never learned to weld, so I'll be bolting things together. The two spring arms attaches to the table in two places; the hammer head arm on top of the table and the arm driven by the motor on the front of the table (And of course it's attached to the drive as well, underneath the table) - In one place there was a piece of plywood between the spring arm and table. I assume this is for vibration and shock absorption I'll want to maintain good vibration control on this thing. The table, pedal bracket and anvil base bolts into the ground separately, but I'm considering attaching it all to a thick steel plate, which I can then put a rubber mat underneath and bolt to the concrete floor in order to make the entire thing a cohesive unit. Thoughts on how to best handle vibrations? I plan on taking the entire thing apart, separating the leaf springs to clean it up, remove rust and make sure all the pieces are in good enough condition that it won't blow up on me. The anvil needs a bit of work, but cleaning that up and making a stand that bolts to the floor should be easy enough (I already made a stand for my 120kg KL70 anvil. Works perfectly) Once again, any assistance or thoughts on this is greatly appreciated. Quote Link to comment Share on other sites More sharing options...
SLAG Posted December 19, 2018 Share Posted December 19, 2018 Mr. S. Hammer, I suggest that you do a patent search. Check out the assignee list (compilation), for Jens Christoffersen company). And / or look under patents for the year 1913 and "helve/spring hammer". Check out U.S.A. and British patents to start. (also European patent office data bases. (using Derwent?). The latter service is not cheap. Google patents is a good place to start your search. Also the U.S. patent and trade mark office site. The patent specification, claims, and drawings will give you a good description & illustrations of the device. Welcome to the site. Happy hunting, tool refurbishing, and merry Christmas. SLAG. Quote Link to comment Share on other sites More sharing options...
Søren Hammer Posted December 19, 2018 Author Share Posted December 19, 2018 Thank you SLAG! I've already done a Google Patent search, but it only lists the name and year. The Danish patent service doesn't have anything dating back that far (I assume they never bothered bringing it online) - I'll see if I can find something in UK and US patent databases. Thus far I've not been able to find anything on the company that made these, though I might have some luck asking around in the Danish blacksmith community Quote Link to comment Share on other sites More sharing options...
SLAG Posted December 19, 2018 Share Posted December 19, 2018 Soren, Try searching for "patent data bases" on duckduckgo.com or dogpile.com. I am surprised that google did not have what you are looking for. If that does not prove availing contact the Danish patent office and ask them. As a last resort contact a patent law firm. Describe your search effort briefly and ask them for a suggested search method. SLAG. Also, you may have some luck at www.pat2pdf.org I have not used this site. also, try www.patft.uspto.gov (this site will give some part of a patent but you can get the full patent text elsewhere. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted December 19, 2018 Share Posted December 19, 2018 Did you write the museum and see if they had any info on the motor if it came with it? I was once at a small museum that had an original Sibley tent stove on display. They were quite happy to help me take detailed measurements of it as I had a Sibley tent replica made for the filming of the Blue and the Gray; but not the stove... Quote Link to comment Share on other sites More sharing options...
Søren Hammer Posted December 19, 2018 Author Share Posted December 19, 2018 4 minutes ago, ThomasPowers said: Did you write the museum and see if they had any info on the motor if it came with it? I'm assuming neither of the hammers had motors attached - The belt is almost 2 meters long when looped so I doubt it's been wired up recently (The belt is also broken, and I know the seller never used the hammer, so wherever he got it from broke it), - I never asked where the seller got the hammer from or what museum he gave the twin to, but I'll have to ask him now that you mention it! Quote Link to comment Share on other sites More sharing options...
Judson Yaggy Posted December 20, 2018 Share Posted December 20, 2018 Just to start a hand made leather belt should provide adequate service, save your money for when you know everyting else works and then upgrade the belt to something modern. As for motor HP please weigh the head/hammer/tup, note the pulley diameters, and let us all know those numbers and we can roughly estimate motor HP and RPM. Quote Link to comment Share on other sites More sharing options...
Søren Hammer Posted December 20, 2018 Author Share Posted December 20, 2018 14 hours ago, Judson Yaggy said: Just to start a hand made leather belt should provide adequate service, save your money for when you know everyting else works and then upgrade the belt to something modern. As for motor HP please weigh the head/hammer/tup, note the pulley diameters, and let us all know those numbers and we can roughly estimate motor HP and RPM. I'll get some precise measurements later, but the pulley the belt sits on is about 10-11 inches in diameter I'd estimate. The piston wheel (I actually don't know the English name for it) that drives the shaft that moves the hammer is somewhat smaller than the pulley. I'd wager 7-8 inches in diameter where it connects (Though the wheel itselfis larger). The hammer head I'd estimate to weigh 20 - 30 kg (44 - 66 lbs) - I can detach it an weigh it, but I assume the weigh on the arm itself is important too. The entire arm is probably 70 - 100kg (150 - 220 lbs) I'll edit this post and the original once I got precise measurements. Quote Link to comment Share on other sites More sharing options...
Søren Hammer Posted December 20, 2018 Author Share Posted December 20, 2018 Apparently posts can't be edited so here I've got some actual measurements. The hammerhead weight (still on the arm, can't detach it easily) is about 20-30kg (44-66lbs) - I weighed it with just the head on the scale (20kg) and half the arm resting on something else (30kg), so read it as a estimate. The entire arm is 75kg (165lbs) and 40 inches long. The belt pulley is 7 inch diameter. The drive shaft wheel is 3,5 inch diameter. The flywheel, in case it matters, is 12 inch diameter. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted December 20, 2018 Share Posted December 20, 2018 Posts here can be edited for only a short while after being posted. Quote Link to comment Share on other sites More sharing options...
JHCC Posted December 20, 2018 Share Posted December 20, 2018 Welcome to IFI, Søren Hammer. If you haven't yet, please READ THIS FIRST!!! Very cool hammer. I look forward to seeing how it comes together and how it works for you. Quote Link to comment Share on other sites More sharing options...
Adair Posted February 11, 2021 Share Posted February 11, 2021 I sure would love to see some progress on this hammer, or any indication of how it was configured. Any news Søren? -Adair Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 11, 2021 Share Posted February 11, 2021 He last visited in June of 2019; so don't hold your breath for a reply. Quote Link to comment Share on other sites More sharing options...
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