[fiscus]

I'm about to build a small press, for doing differential and general car stuff.

How many tons do I need? I'm thinking either 12 or 20.

I want it to come apart when I'm not using it for easy storage.

Check out my drawing I made:



Think it's big enough? what jobs would this be too small for?

I plan to sleeve the round holes with steel pipe.

Think 1" roundbar is strong enough to not deflect when the sliding supports are a few inches out?

[powerrodsmike]

The 2" square tubing will bend and distort at 2 or 3 tons. The 1" is ok. 12 tons is ok 20 tons would be better, you can do a little fab work with it then. My shop press is 55 tons...and I wish it was bigger..

Many bearings take 3 or 4 tons to push on and off.


Use at least 4" X 2 channel for the ends, table and top plate. 6" is better for the ends, as you need the clearance between your table plates to fit stuff. Double up the top plate and put a 3/8 plate on the bottom for the bottle to push on. Put some kind of reciever bushng on the bottom of your jack bottom plate so you can adapt different arbors depending on the job you need to do.


I'd make it a little taller, you will run out of room doing axle bearings.


I think I have a set of plans for one at the shop, I'll scan them in for you.

Hope this helps, mikey

[grouch]

Take a look at this 10 ton DIY press. Note at the bottom where the guy says:

10 tons sound a lot, but they are not, depending on what you do. When bending sheet metal with the rubber bars, it requires more power than with conventional press brakes with a vee die. For what I did with bending, it was enough. But for pressing crank shafts or ball bearings (of your car), 10 tons are the lower limit.

I should have made the two vertical columns stronger. They are at their limit. I don't remember how I messed up my math, but when I recalculated what I have halfway built it showed up.

Here's another one - 20 ton shop press

Also note the comment:

I have built a 20 ton air/manual shop press and it is a scarey hunk of metal. First used 3x4 channel, bent the hell out of the whole mess, then (thanks to a good friend who ownes a scrap yard) used 3" c channel.

Finally, here's a press with dimensioned drawings. Some text from that one:

The frame I built was constructed of 20-inch rectangular tubing with 3/16th-inch wall thickness; it's what I had on hand. You could also use channel iron, or even angle iron welded together along the edge to form a channel. The uprights are 54 inches long; the top piece is 23-3/4 inches long.

Darn. All 3 examples reinforce Mikey's advice. Reality just doesn't like me.

[powerrodsmike]

It pays to take note of what others build that works.


That way you can build your own..

When I first saw that one guy said he used 20" rectangular steel with a 3/16 wall.....I thought, holy crap, where does he have the room for that monster.....But in the drawing it shows a more civilised dimension...

That press is basically a knockoff of the arcan, HF, carolina presses, and many others I'm sure.


I know that when you exceed the working capacity of a press, violent things happen. I bent the table on my 55 ton, and also caused a breach in a couple of welds on the press ram.


Later, mikey

[freecontact]

I reckon boxed "I" beam girder might be stronger for the top crossbar.......with squared/rectangular vertical ends to slide up and down two squared/rectangular poles/"I" beams welded to base plates that are dyna-bolted to the concrete......but make sure the vertical ends are of enough length to allow two 1 inch rods either side to secure it's slide......You should have/allow adequate width to allow for two bottle jacks when you need the extra power press......Hope it oils the cogs anyway cuzz....
Crash Nullage...(P.S. Telescopic like slide)

[Kevin45]

1" is kind of light for the bars. Especially if you pot any tonnage to it. I would gp at least 1 1/2" diameter and something a little stronger than cold rolled steel. Maybe some 4140 or some 0-1 tool steel.

[awert]

I was also going to build a 20 press, my only question is how the heck does one get all the vertical holes??? I assume 3/4" is big enough, yes i know they make 3/4" drill bits, but that is a lot of drilling, and a cheap bit will never hold up. Is there something else around??

[NEW INTERIORS]

Buy a good bit,And take your time and have fun.The thing's that take time to do,Is usually the one that come out the best.

This is a press break,I just made.I know you are building just a press.

[leldai73]

a good bit is probably a good place to start. lay out the holes and center punch them. then head for the drill press because you wont be doing it with a hand drill. start with a small bit and work your way up to 3/4 in increments of 1/8 - 1/4 of an inch or whatever your comfortable with. with a good rigid set up in a mill or a heavy drill press and with the work securely clamped you can go directly to 3/4 with no trouble after you drill a pilot. which brings me to my next point. your going to want to clamp the work to the table some how probably in a vice. This seems like a pain in the a** but if a bit grabs the work could spin on you, and why take any chances.

another important thing to pay attention to is rpm. rpm is determined by a simple equation

4 X recommended surface feet / diameter of cutter

recommended surface feet for mild steel is 100

so with a 3/4 inch bit drilling mild steel the equation is

4 X 100 / .750

your rpm is going to be 533. it doesn't hurt to go a little below this figure think of it as a speed limit.

not to undermine the mod here...but any thing other than mild steel is a waste of money. buy some good heavy walled mild steel tubing. or heavy c-channel.