Arbor vs. Hydraulic press.
I am interested in buying a “Press”. There seem to be two general kinds: (1) Manual Arbor Press, (2) Hydraulic Press. Below are pictures of each kind. The hydraulic presses seem to be notably cheaper and apply much higher pressure. ( $1,950 vs. $2,750 and 50 Ton vs. 7 Ton in this example.) Would anyone be willing to compare and contrast these two types of presses and talk about guidelines to use when choosing one type over the other? Why would one want 50 Tons of pressure? I seem to need a press mainly to insert and remove pins and bearings when trying to fix machinery.
Thank you, Bruce
The manual press will provide a much better feel for pushing pins, bearings, and shafts on an assembly. They normally have longer strokes for the ram travel which makes hand broaching a little more practical if you have strong arms. The KR Wison like that hydraulic one you show will give more pressure when you have something really stuck. The hand crank on the ram will still let you push about 3 ton manually but there is alot of drag created by the hydraulic ram and oil.
I have a KR Wilson 75 ton and a few small rack and pinion manuals. The hydraulic is what gets used all the time.
The KRW presses are the best of both worlds. Saves lots of space to have two presses in one.
Those are both nice looking presses.
The main advantage to an arbor press is that you get "feel." A hydraulic press has little or no feel (other than the frame creaking as it loads up.) With a hydraulic press you can rather easily warp or bend the shaft you are pressing the bearing off of or on to. Most pin pressing work is best done in an arbor press. You need to get and use the tool that is the right size for the job you are doing. Unless you are doing fairly big stuff I doubt that you need more than a 20 ton hydraulic press. A 20 ton will handle all automotive sized work. You may be better off getting one of each rather than trying to do all your pressing with a single big press.
You also need to be very careful with setups and tooling with a hydraulic press. The work can load up like a big spring and all of a sudden it lets go and you have an axle shaft bouncing at you that was just launched with 50 tons of pressure. You need really solid setups supporting the bearing and/or the shaft in the press. This is not the time to improvise with bits of scrap and pipe. An indispensable tool for bearing R&R is a good bearing splitter.
OTC Tools makes a line of pullers and accessories that I have found to be of good quality.
A typical hydraulic press is more versatile than an arbor press particularly for the machine repair work you're contemplating. It has a much larger work envelope for one thing. You'll eventually need some tooling for bearing removal and installation. It's far easier to utilize that sort of tooling on a hydraulic press, the tooling is designed for hydraulic press use. The increased tonnage is another advantage. What size press you need is entirely dependent on the size of work you'll be using it on.
Be careful though, a hydraulic press can be very dangerous in the wrong hands. You haven't lived until you've been near someone using one on a bad setup and have it fly out. Bad scene.
OT: Bruce, check PM regarding vent cover.
Arbor presses for me are quicker to use but the tonnage of a hydraulic is it's strong point. Here's a little something done with a 40 ton hydraulic. Maybe my press is in the wrong hands I came up with this for a self containtained die set. Punching .070 thick stainless steel. The hardened block self aligns the puch and the slot in the side is the material feed through. This is what you do when you don't have access to a true punch press! Last pic is the final product after several more operations.
You can Press form quite a bit with the hydraulics. It just all depends on what your intended use is and that should be the critiria for your selection
I bought a HF 20 ton and use it way more than I thought I ever would.
I did have to modify it. I added 16" to the legs so I didn't have to get on my knees to use it. (those chinese are short little guys) And I took an old boat trailer winch and rigged it to the work table so I could raise or lower it with the plates and work on it.
Some things I do with it; I have straightened 1/2" plate and brackets, cut 3" circles out of 1/4" neoprene, straightened 1 1/2" shaft. After a while you get a feel for how much pressure you are applying.
I this case I would buy the KRW press. One of KRWs selling points was that you could use there press like an arbor press by using the hand wheel. Most people don't want a arbor press as big as the Greener 5c . I have a Manley press with the arbor press on the side and I use that about 98% of the time. Ken
I just got my first hydraulic press about a month ago and it's no heavyweight...Enerpac 30t.
But, I've never come up short pushing mostly bearings and broaches with my arbor presses. Really, about a #1-1/2 (3 ton ratcheting) would do about 90% of the jobs...a few times I needed the larger presses, sometimes for the "swing" or "throat" and other times for the actual tonnage.
re: 'feel' on a hydraulic press...if you get one with a pressure gauge built in, with a little practice it's just as nice (you use 'instinct' instead of 'feel'). As others have (justly) pointed out, they DO have a margin of danger. I once had an an aluminum casting burst (literally) because the (steel) roller bearing I was pressing out was seized- shrapnel everywhere.
For repetitive work, arbor presses have their own safety issues as well. At one sweat-shop I worked at, they had an arbor press at one workstation pressing 5/8" dowel pins into a housing. I watched I don't know how many (in total) guys cycle thru that work station, but for sure 3 of them went out on disability due to rotator-cuff damage- in a 6 month span.
on edit: my choice hands-down is a hydraulic press over an arbor press (even a hyd without a gauge)
Last edited by 77ironhead; 11-10-2008 at 08:21 AM.
Reason: added comment
I have a KRW press and love it. As previously said the ability to use it like an arbor press is amazing. Mine is a 25 ton model and I need all 25 tons sometimes to press stubborn parts of when doing work on my truck. The KRW is the perfect press for me.
I find that a geared (manual) press and a hydraulic press are not quite the same. I have a small, 1/2 ton, manual "C" press, and a small H-frame hydraulic press (Enerpac 10 ton bench press).
The manual "C" press is much faster to set up and use, gives good feed-back. Faster because the ram is almost instantly adjustable for the height of the job and quick/easy to cycle. For sensitive or repetitive work it is hard to beat.
My hydraulic gets used when the job is physically too large or beyond the capacity of the dinky manual "C" press. Usually most of the time spent using a hydraulic is in the set-up or the cycle time. On hydraulic presses you seem to be forever raising/lowering the platen due to limited ram length.
Having said all that, I would not want to be without either one of mine. I went for years without, using/abusing various machinist vises as substitutes for presses.
Look around a bit, you should be able to find a deal on a good used manual "C" press. My hydraulic press was salvaged from the scrap pile and rebuilt by me.