[TheForge] half round staock

Mon Mar 10 11:30:09 EDT 2014

Yeah, terminology thing.  Direct contact would be a pretty bad mistake.

Problem is, I don't know how this unit works and ain't about to take it
apart to find out.

FWIW, you can manually keep the thing actuated to maintain pressure, but I
know no way to maintain it at a height AND at pressure -- i.e., to prevent
subsidence.  Not important in my case.

And this press design (made with this jack) works fine for welding
"Damascus" billets.  I've done it and seen it done -- just not on my own
press.

Bruce
NJ

On Sun, Mar 9, 2014 at 10:51 PM, Jerry Frost <akfrosty at mtaonline.net> wrote:

> No Bruce, "air over hydraulic" in no way implies direct air hydraulic oil
> contact. I know of two basic air/hydraulic systems. #1 is a compressed air
> cylinder that drives a hydraulic master cylinder. #2 is the air motor
> driving a hydraulic pump system you describe. No direct air/hydraulic
> contact in a properly functioning system. Heck, the sure sign you have air
> in your hydraulic fluid is spongy cylinders or snap start motors. The air
> compresses till it overcomes the resistance and once the cylinder or motor
> begins to move it jumps.
>
> Jer
>
> -----Original Message-----
> From: theforge-bounces at mailman.qth.net
> [mailto:theforge-bounces at mailman.qth.net] On Behalf Of Bruce .
> Sent: Saturday, March 8, 2014 2:35 PM
> To: Blacksmithing List Sponsored by ABANA
> Subject: Re: [TheForge] half round staock
>
> Well now you've got me wondering.  What air over hydraulic apparently is
> NOT
> is air over hydraulic!  HF doesn't even call it that -- I think I picked
> that up from the local guys.  ("Air over hydraulic" would imply that the
> air
> pressure is impinging directly upon the reservoir of oil, thus pressurizing
> it.  That could be incredibly dangerous for reasons of ignition of oil by
> high-pressure air, or of sub-cutaneous injection of oil (like can happen
> with a paint sprayer).
>
> Rather, it seems to be air operating a hydraulic pump -- it putt-putts away
> as you actuate it, just like the little engine that could.  Hence, I rather
> expect that's exactly what's going on, but haven't done the homework to
> find
> out.
>
> So I called up the HF manual:
> http://manuals.harborfreight.com/manuals/95000-95999/95553.PDF
> There's a part (that goes putt-putt) they call the "air motor".
>
> However, they don't give an explanation of how it works, so all of this is
> just surmise.
>
> Now, the instructions are pretty clear that these jacks are for lifting,
> not
> for holding.  So Frosty's concerns have some merit in any event.  That may
> well be true, however, for ANY hydraulic jack.
>
>
>
> Bruce
> NJ
>
>
> On Sat, Mar 8, 2014 at 3:26 PM, Jerry Frost <akfrosty at mtaonline.net>
> wrote:
>
> > I've wondered how well air over hydraulic cylinders would work inn a
> > forging press. I know they're fast but how true is the 20tn. Rating?
> > There's a difference between lifting 20tns. and a solid 20tn. push.
> > Air is compressible while hydraulics are incompressible so a jack may
> > lift 20 tons but it's going to have some spring.
> >
> > Don't sweat ugly welds with flux core welders, they're pretty famous
> > for it and I can't imagine what I'd use HF welding wire for, maybe
> > reinforcing in a cast refractory forge liner? Oh wait, if I can't get
> > the needles I trim a stainless steel brush. My wire welder is a Hobart
> > 120 Handler and I use it as GMAW with 75/25 gas and for light welding.
> > For heavy work I have a Lincoln Ranger 9 welder generator. I have a
> > LN-25 fire feed for it with Lincoln's 7018 equivalent flux core wire.
> > I don't recall the actual wire designation because I almost never run
> > enough bead to need the wire, I usually run stick.
> >
> > My first wire feed was a little Italian import 120v welder designed to
> > use the 2lb. spools but it was an easy mod to mount a spool holder on
> > it's back and buy regular spools. I was really bummed when a cheap
> > part failed and none were available this side of the pond. (grrrrr)
> >
> > Jer
> >
> > -----Original Message-----
> > From: theforge-bounces at mailman.qth.net
> > [mailto:theforge-bounces at mailman.qth.net] On Behalf Of Bruce .
> > Sent: Friday, March 7, 2014 1:50 PM
> > To: Blacksmithing List Sponsored by ABANA
> > Subject: Re: [TheForge] half round staock
> >
> > Little digging out needed in NJ recently.  It's been mid-30's, mostly.
> > I spent some time getting my forging press "on-line".  We made these
> > in an NJBA workshop about a year back, but I didn't have a table for
> > it so never got it up and running before.  It's a wicked thing --
> > powered by a HF 20-ton air-over-hydraulic jack.  I tested it on some
> > bent stock that was inconvenient (because too long to handle) to
> > straighten by hammer and anvil.
> > I've used one to forge a "Damascus" billet.
> >
> > FWIW, the HF 90-A flux-wire welder (120 VAC -- works off a standard
> > circuit) is on sale this weekend only for $80.  Best price I've seen
> > for it.
> > I paid about $10 more for mine. It won't replace a big blue, but it's
> > portable and WILL weld fairly heavy stock if you pre-heat the stock
> > (with an ordinary propane torch).  I've been welding 1/2" and 5/8"
> > square stock to a 1/4" plate.  My welds are real sloppy, but that's
> > probably more me than the welder.
> >
> > One tip -- throw away the crap HF flux-core wire and use a name brand.
> > Joseph Fazzio's in NJ advertizes name-brand 10-lb spool for less per
> > lb than HF sells their crap 2-lb spool .  (You'd have to rewind onto
> > the smaller spool or modify the HF welder to hold a 10-lb spool --
> > which reportedly has been done.)
> >
> > Bruce
> > NJ
> >
> >
> >
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