hindsight Posted May 9, 2014 Posted May 9, 2014 Pressing 2.5cm(1in.) diameter rockets is tedious using a manual pump and I would like to convert to an hydraulic powerpack to drive the double acting 7.5cm(3") diameter, 53cm(21in.) long cylinder. The press is stationary, so mobility is not an issue. There are many more DC power-packs with solenoids for double-acting(DA) cylinders available here at a reasonable price, than AC. And pendants pre-wired for DC powerpacks also seem more readily available. Presumably, if AC power outlets are available, a converter would be used to power the powerpack, but I need help choosing something appropriate. Alternatively, what are advantages/disadvantages of using an AC powerpack. This is completely unfamiliar territory for me and any help is appreciated.
skid68 Posted May 9, 2014 Posted May 9, 2014 Pressing 2.5cm(1in.) diameter rockets is tedious using a manual pump and I would like to convert to an hydraulic powerpack to drive the double acting 7.5cm(3") diameter, 53cm(21in.) long cylinder. The press is stationary, so mobility is not an issue. There are many more DC power-packs with solenoids for double-acting(DA) cylinders available here at a reasonable price, than AC. And pendants pre-wired for DC powerpacks also seem more readily available. Presumably, if AC power outlets are available, a converter would be used to power the powerpack, but I need help choosing something appropriate. Alternatively, what are advantages/disadvantages of using an AC powerpack. This is completely unfamiliar territory for me and any help is appreciated.This is the power pack that Rich Wolter, of Wolter Pyro Tools uses with his press. It is AC powered.If you know anything about Rich Wolter, you know this power pack must be a quality unit.http://www.northerntool.com/shop/tools/product_200329732_200329732?isSearch=105871-2301
Mumbles Posted May 9, 2014 Posted May 9, 2014 I know quite a few people who use 12V DC powerpacks. They run them off of car batteries or a car battery charger typically. I attached an article I have from someone who's built several of these. It's kind of long, but hopefully will help to answer some questions.rocket press.pdf
hindsight Posted May 9, 2014 Author Posted May 9, 2014 skid68,Thanks. Yes, Rich Wolter is a quality guy. The AC powerpack you linked looks good. It would require separate valving as it has no solenoid valve function. I know people have used log-splitter valves to work with a DA cylinder.Mumbles,Thank you, sir. After wading through Dan McMurray's article and gleaning what applies to my construction, it seems that the Stone SPX DC-60SF will be the ideal powerpack. As the name implies it's a DC unit (solenoids for DA with center hold)and he used an automotive battery to power it --with no discussion of powering it via a convertor/AC source. Are you saying that the DC powerpacks can be powered directly from some battery charger, or would the current draw for the unit likely exceed a charger's capacity? i need a bit of direction here and would like to eliminate the use of a battery, if that's reasonable. This an education in progress for me on this project and any assistance is gladly accepted.
hindsight Posted May 9, 2014 Author Posted May 9, 2014 This is the unit Dan referred to: http://stonehydraulicstore.com/?product=dc-60sf-12v-dc-solenoid-operated-power-uppower-down. Don't see amperage listed, but comparable units draw in the 200-300 amp range. I'm guessing an AC to DC convertor would be required. Any suggestions?
Mumbles Posted May 9, 2014 Posted May 9, 2014 To be honest, I don't know if the charger on it's own would work or if you need a battery in there as well. The ones I'm most familiar with all use batteries. From a little searching, it would seem that the battery is required to achieve the 200-300 amp load. I'd guess that low power situations, like raising and lowering the ram under no load could be done with just the charger, but to really get the most out of it, you need the high amperage of the battery itself to power the press under periods of high load. This is all speculation based upon what I've been reading, but honestly am not entirely sure.
hindsight Posted May 10, 2014 Author Posted May 10, 2014 Mumbles,That makes sense. On the other hand (one of electrical engineering types will correct me) if a 12VDC pump draws 250amps, that would approximate a 230VAC circuit drawing less than 15amps through a convertor, which is feasible using typical shop wiring. Just weighing the options before biting off on a purchase of this size.
hindsight Posted May 19, 2014 Author Posted May 19, 2014 Okay, there is a 250-300amp 12Volt DC powerpack that should arrive soon, and per Mumble's suggestion, it will be powered by a battery and battery charger. Presumably, the battery will have to handle 300amps (peak?) but I need recommendations for the battery(deep cycle?) and for the charger. Specifications and model advice would be appreciated.
dagabu Posted May 20, 2014 Posted May 20, 2014 (edited) Grab a 24MS marine Battery and a Schumacher Se-1275A 2/12/75 Amp Automatic charger, it can charge 24/7. Did you buy a tank too? That page shows no tank comes with the pump... BTW, there are metric butt-load of powerpacks on eBay for 1/2 that price that come with a tank. You may wish to look there and maybe return yours. I have THIS ONE and it has served me well, 2 full gallons of fluid keep from boiling even in 100° weather. Dave Edited May 20, 2014 by dagabu
hindsight Posted May 20, 2014 Author Posted May 20, 2014 dagabu, It is a privilege to have access to a reliable resource like you. My post above with the link to Dan McMurry's recommended powerpack was misleading, since the unit I eventually ordered was a surplus unit with almost the same price and specifications as yours (including a 2.5 gallon reservoir). Grace smiled upon the foolish. Next step is to find a source available here for the charger and battery, or equivalent, that you recommended.Thanks again! --hindsight
MrB Posted May 20, 2014 Posted May 20, 2014 Just for the EU players following this thread, i think this is a suitable replacement. Cheaper then shipping it across the ocean, and, if your in EU, no customs...Slightly outside my scope currently, but should i decide to build a press, i'd buy one.B!
viziers Posted June 8, 2014 Posted June 8, 2014 For all you hydraulic press people, can the following press be converted and by that I mean can the hand pump be replaced with the power pack dave listed above that I listed below? Or will that piston not support the power pack? http://www.ebay.com/itm/SPX-Stone-Fenner-12VDC-Double-Acting-Hydraulic-Power-Unit-Pump-Monarch-Chief-NEW-/131168586293?pt=BI_Pumps&hash=item1e8a41ca35 http://www.northerntool.com/shop/tools/product_200332763_200332763?cm_mmc=Google-pla-_-Metal%20Fabrication-_-Shop%20Presses-_-145208&ci_src=17588969&ci_sku=145208&ci_src=17588969&ci_sku=145208&gclid=CNLyvd2D674CFShnOgodTnoA5A vizi
dagabu Posted June 8, 2014 Posted June 8, 2014 (edited) No, sorry but that is a DA powerpack, the press is SA, there needs to be two hoses on the press for the DA powerpack to work. THIS one is SA, it would work with the press but it still needs a way to return the cylinder to the up position when you are done. Also, there are a lot of DA powerpacks out there for half the money, dont be worried about rebuilt ones, they have all new guts but look rough. Edited June 8, 2014 by dagabu
viziers Posted June 8, 2014 Posted June 8, 2014 Ahhh ok, so I would have to swap the whole assembly.... vizi
ddewees Posted June 8, 2014 Posted June 8, 2014 Wouldn't the SA one work, and the ram just return up like it does with the hand pump? He wouldn't have power up, but it still moves pretty quick. I have a similar press, and that pump Dave linked to seems perfect.
dagabu Posted June 9, 2014 Posted June 9, 2014 Wouldn't the SA one work, and the ram just return up like it does with the hand pump? He wouldn't have power up, but it still moves pretty quick. I have a similar press, and that pump Dave linked to seems perfect. Sadly, the Northern press shown uses a spring return located in the pump assembly, not the ram. The ram will not move up if you detach the pump. I know, this press looks really good to the eye but if you have a Northern close to you, go check one out, they offer a very short stroke (7") and is only 10 ton and has a 6" range at the top stops. THIS press from Harbor Freight is an A-Frame and can take the standard pump, an air-over pump or even a DA cylinder (with some adaptation).
hindsight Posted June 9, 2014 Author Posted June 9, 2014 Along these lines, I now have a reinforced Harbor Freight (same Chinese manufacturer, different company) 12 ton H-frame, to which I added a 7.5X 54cm DA cylinder, driven by a powerpack very similar to the one you are looking at, viziers. The frame allows the long travel of the ram. The DA cylinder cost 37Eur (50USD) on Ebay. It is early, but so far the setup works great.
hindsight Posted June 9, 2014 Author Posted June 9, 2014 Truth is that my design was influenced in part by dagabu's pix of his press. And his help with the battery power, in this thread, was valuable.
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