shop press

[Mike]

Hi

As i coudn't fi d to much about this. What type of press would i need to press Whistle rockets up to 1lb and bp rockets to 1"?

 

Would a 6ton press be sufficient?

If not, for what would a 6 ron press be sufficient?

 

I could get a use one from an shop for just a carton of beer, but don't wan't to crowd my space with a press not sufficient for the real work.

[jessoman]

That will be fine mate, just make sure you use a p2f gauge and get some poly carb on for the blast shield.

 

You can do most with that size press. I use a 20T press and it barely puffs when I press my smaller 1lb motors.

[nater]

Just make sure you have enough working height for 1" motors. 1" BP motors are typically 10" long tubes. With my tooling and PtoF gauge, I need 24" of working height in the press to fit them.

[jessoman]

Yes! Nater is very correct, so important! I even made a mental note to say that has I started writing, silly me. A taller press makes things easier. I have about 4ft of room and it's painless.

[markx]

Just make sure you have enough working height for 1" motors. 1" BP motors are typically 10" long tubes. With my tooling and PtoF gauge, I need 24" of working height in the press to fit them.

One can also make an adjustable height press.......use four threaded rods as the frame and secure the endplates to the rods with nuts and washers. The bottom plate can be welded if one wishes to. But by loosening the nuts on the top plate and moving them along the threaded rods one can regulate the height of the press frame to suit the motor height. Pretty useful when dealing with a variety of motor dimensions. But the original point remains valid....make sure you have enough headspace (adjustable or not) to accomodate your bulkiest motors.

[nater]

Yep, just like this: http://www.amateurpyro.com/forums/topic/7292-semi-portable-press/

 

I do adjust it as needed. I have some spacer plates, but I prefer to keep everything as low as possible to help keep everything aligned.

 

It has served me well, and I recommend it to anyone who is not quite ready to invest in a press with a power pack or who needs one that is easily portable. I am getting real close to upgrading though.

Edited May 14, 2014 by nater

[markx]

Yep, just like this: http://www.amateurpyro.com/forums/topic/7292-semi-portable-press/

 

 

Whoa....those hose clamps, theres like a million of them! Do you have to loosen and tighten every single one of them to get the motor out? I machined a piece of steel pipe the length of the motor (more or less) that fits snugly around the pyrotechnic tube. And I have a jig to press the ready made motor out of the steel pipe after having completed the loading....works like a charm and no clamping, no moving parts. The steel tube can be ever so slightly camfered to aid the releasing of the motor. You need a different one for every different diameter motor...but then again, how many different ones can you usually keep making

I also fitted the pressure gauge directly to the jack....drilled a hole into the base and into the pressure chamber from there. Tapped the exit and fitted a standard 200bar gauge. No separate block between the jack and press frame this way, helps to keep the height down and things more stable. As a downside a piece of drill chip has manged to lodge itself into the one way valve somewhere and I can't get the bastard out from there. As a consequence the jack will not hold a stable pressure any more, but it works fine for pressing motors.

[Mike]

Thank you for the advices. I asked and it where one of these 105mm presses, like you get em on ebay for 60 . So not worth the space. I'm not sure if i go with one of the 10 tons presses, which allready have an gauge or if I'm going to build an own. The 10 ton ones can be gotten for 180 so. Have to see how much the materials would cost buold an own.

[nater]

Markx - you are correct about the hose clamps, it is a pain to tighten and loosen them all. It is necessary for these types of sleeves. A support like you describe is better. Without machining capabilities, my options are the expensive supports from Firesmith or Wolter, or use a split PVC and clamps.

 

Tapping the jack is also a good practice. I never bothered since opening up those bottle jacks is a pain and I don't have a set of taps and dies. It is better than stacking the tooling and PtoF in line with each other.

 

Part of the reason I have not bothered making those adaptations is knowing I would eventually get a hydraulic press with a power pack to avoid the hand jacking.

[markx]

Markx - you are correct about the hose clamps, it is a pain to tighten and loosen them all. It is necessary for these types of sleeves. A support like you describe is better. Without machining capabilities, my options are the expensive supports from Firesmith or Wolter, or use a split PVC and clamps.

 

There's gotta be a better way to rig up the support....these clamps are crazy Do you have welding capability? I mean you could find a suitable steel pipe, split it lengthwise, weld nuts to one half and pieces of steel to accomodate bolts to the other. Then secure that around the paper tube...maybe you can get away with fastening just 2 bolts if dimensions and wall thickness allows. There are probably countless more ways to improve on the situation....what about casting a suitable support tube/block out of glassfiber epoxy or steel enforced high strength cement?

[nater]

I don't have a welder either. We have one at my part time job, but I'm not 100% confident in my ability to make a secure weld. In the book Amatuer Rocket Motor Construction by David Sleeter, he describes a simple support make from a split steel pipe with flanges welded on it and bolted shut.

 

While the clamps are a pain, I actually like the idea of split tubes and clamps. The OD of tubes is not very consistent from batch to batch, this presents another problem when you have a machined support. I'm sure there are better ways to support a tube. People have come up with a handful of ways, but they all end up trading one problem for another.

[dagabu]

Mike,

 

I have a press ready to run for sale, it includes EVERYTHING you need for your rockets! Press, power pack, deep cycle battery, remote, Polycarbonate shields, etc.

 

I will include delivery CONUS. Message me if interested.

[Mike]

Sry dag but i relally 2ould like your press, but the EU is quite far away from where you live.

 

I looked around for press design and how to build one. And decided if i build my own one it willbe on

Of the square design with 4 of the screw rods (one at each corner, 1m long).

Looked for some material and maybe this could be the way to go. But there where some informations i really missed.

 

If i build it based on a 10 ton Jack.

Which diameter would the 4 rods need to have (Made out of V2A)?

And how thick would the baseplate and top plate need to be if made from common steel i could get 16 mm or 20mm quite cheap.

Also would a size of 10x10x40" be big enough? This would result in around 20" space for pressing + PTOF.

 

Also does someone have experience with modifing a short way hydraulic ram innto a PTOF gauge?

 

 

On the other hand I'm thinking about going pneumatic. Does someone have experience with that? What type of air cylinder would i need for such a press?

[dagabu]

Sry dag but i relally 2ould like your press, but the EU is quite far away from where you live.

 

I looked around for press design and how to build one. And decided if i build my own one it willbe on

Of the square design with 4 of the screw rods (one at each corner, 1m long).

Looked for some material and maybe this could be the way to go. But there where some informations i really missed.

 

If i build it based on a 10 ton Jack.

Which diameter would the 4 rods need to have (Made out of V2A)?

And how thick would the baseplate and top plate need to be if made from common steel i could get 16 mm or 20mm quite cheap.

Also would a size of 10x10x40" be big enough? This would result in around 20" space for pressing + PTOF.

 

Also does someone have experience with modifing a short way hydraulic ram innto a PTOF gauge?

 

 

On the other hand I'm thinking about going pneumatic. Does someone have experience with that? What type of air cylinder would i need for such a press?

 

The threaded rod type jacks do move, that is really bad for rocket motors. I have both threaded rod (1/2" grade 5) in all four corners as well as fully welded butt joints and it is very stiff.

 

I used common structural steel box, 1/4" thick to make the top and bottom and common structural steel box 1/8" thick for the vertical posts.

 

Yes, 10"x10"x40" would be fine but you may want a little more width than that. I have 11" between the uprights in the inside and wish I had 14" across.

 

There are write-ups for the PTOF modifications around, somebody should be able to help you out here.

 

Pneumatic is good for holding and making small (1/2" and under) embellishments but is impractical and even dangerous when pressing motors. Hydraulics (forgive my guesswork, I don't have my book with me) under static load will become neutral in pressure when load is removed in less that 1:100 the cylinder diameter of travel due to the inherent incompressible nature of fluids.

 

Pneumatic energy only becomes neutral when it reaches the same pressure of the air surrounding you, that means that the ram will continue to travel under force the entire length of the stroke and will remain under pressure at the end of the stroke until the pressure is mechanically relieved.

 

Air is so compressible that it can be used to store enough energy to start motors etc. The problem is that it is much like a spring, it will continue to expand until all of the available energy is expended (heat and volume) while hydraulic energy is spent almost instantly in a static condition.

 

In short, you would need a cylinder so big it would eclipse the press itself in size to use the 120PSI or so a normal tank type air compressor can make the 5000PSI of force you need to safely press a 1" whistle rocket. The compressor would have to run for several minutes to recharge the cylinder for the next stroke as well.

 

There is also the price difference to consider, a 12" pneumatic cylinder will set you back $2000.00 or more, a 3"x16" hydraulic cylinder will cost you around $150.00 from a surplus store.

 

Dave

[nater]

I used 3/4" threaded rod for my press, although if I were building it again I would have used a stronger grade instead of the rod from the hardware store. The plates on the bottom and top are 3/4" steel, 9"x12". As Dag mentioned, there is some movement when pressing tall items like rockets. It is essential that everything it in line and centered over the jack. If everything is not aligned and square, it becomes very easy to get the spindle off center in the tube which can damage it or cause comp to be pinched. This is another reason where a heavy framed, squared press like Dag's is nice. The trade-off is the portability.

[dagabu]

Nate, its completely portable, all you need is a fork truck and a tandem axle trailer.

[Mike]

Hey

I've looked around a bit.

Found an easy way to make the ptof gauge (but also thinking about one of ben's ptof as they would cost nearly the same, depending on shipping costs).

 

So i kept looking for the press. I found the tutorial for building a press on skylighter (the threaded rod type) and looked for all the parts it needs and figured out that it would cost me about 80 + jack to build it.

I won't go all the way and installing a ptof gauge into the jack i would use the ptof gauge ( if i srew up the jack and buy a second one the gauge is cheaper and also could be used at my arbor press).

 

For the commercial press types, i looked and they all are of the H frame type. There are two different types, one type uses a bottle jack and can be gotten for 100 or one usi g a proper hydraulic cylinder for about 200 . Does somebody have experience with those presses? How are they performing (i read they need an x reinforcement against twisting. How god are those presses against the threaded rod type? If they are the better ones, take the one with the bottle jack or the other?

Thank you for all your help.

[jessoman]

Hi mate,

I have the full size- shop press H frame type it is about 6ft tall. You DEFINATELY need to bolt it to the ground as it has a tendency to 'wind up' or twist as you said.

Great idea buying the made up p2f gauge. Mine is on the press so I have to convert and as my press has 20T on the gauge and 2" cylinder. Not much moving on the gauge gives me 10,000 psi on the comp for a 1lber. So if I was pressing anything smaller than 1lb I would need a gauge, and even 1lb I don't have as much accuracy as I would like. I will buy a proper p2f one day, but things have been going well so no need yet.

 

Kind regards,

Jess

[Mike]

Hi

One other question, how big is the difference if the piston of the hydraulic cylinder is comming from the top down or if it travels from the bottom to the top. (So commercial Press vs homemade using a jack)

 

If i go for the homemade one, i decided to go with a hydraulic/pneumatic jack. I found a nice Jack 10 tons, with an common hydraulic pump and an pneumatic engine, for fast moving the jack. It looks much more solid like the cheap jacks and i really like the pneumatic faster travel function.

[dagabu]

Down/Up or Up/Down does not matter but you will find the top ram to be more stable when pressing. Air-over hydraulic is a fine place to start but if you do decide to get serious about pressing rockets, you will be looking for a solid rig with a powerpack soon.

 

I like the A-frame press better then the H-frame, once you square it all up and put a little pressure on the ram, you can buzz a bead around all the joints and let it cool. Once it is welded solid, it shifts very little and it is transportable. My upgrade was an air-over jack with the gauge modification in the base.

 

The press runs $130.00 and the 12 ton air-over jack runs $80.00, the gauge runs $11.00 at Harbor Freight.

[ddewees]

if you do decide to get serious about pressing rockets, you will be looking for a solid rig with a powerpack soon.

 

 

Ain't that the truth...

[dagabu]

I have heard it said a hundred times, pyro isn't a poor mans hobby...

[ddewees]

Hey Dave,

 

You see any need for getting a cylinder larger than 3" diameter? I think I might go down the cplmac route, and start making 3" ID rockets... but don't want something ridiculously large. He seemed to be able to get away with moderately low pressures on his motors.

[hindsight]

I have heard it said a hundred times, pyro isn't a poor mans hobby...

dagabu-- Not at the outset, but one winds up that way . While I have your attention, if you will excuse the imposition, I'd like to hijack you to a related thread where maybe you would help: http://www.amateurpyro.com/forums/topic/9589-hydraulic-powerpacks/?do=findComment&comment=125752

 

By the way, dag, thanks for posting those before and after pictures. We thank God who gives the miracle of modern medicine the power to assist in your repair process.

[Mike]

Hey

I look around a little more and found some quite interesting parts. First a hydraulic hand pjmp at the scrap yard for 5 .

 

Also found a guy selling new hydraulic cylinders. There was one I really found intersting 43 mm piston diameter (2.25 square inch) and rated 10 tons at 617 bar with connector for a pressure gauge. Working in one direction with internal return spring.

 

Now I'm not sure if that cylinder would be ok (specially because of the 617 bar and most 12v powerpacks just do 250).

2nd question, How do i mount such a cylinder into the press?