This 30" machine was just purchased at the local TSC store for $400, not on sale (+6% tax). It's claimed to be suitable for up to 18 gauge steel maximum.
The 30" working width is real, with about another 1/4" maximum. The break bend angle can go tighter than 90 degrees, but I haven't gaged it yet (maybe 135 degrees).
As usual with China-produced products, the manual is very vague/short. There are no recommendtions for shear blade gap, even though the machine includes fine gap adjustment feature.
The shear cutting blade relief angle is stated to be 5 degrees.
Thanks to the recent RCM discussion "Clearance on shear blades?" (Oct 2009), I believe that a gap of about .002" would be good, not knowing what specific steel (Chinese grade) is used for the blades.
We've been testing the machine, using new 20 gauge steel (measures .036"), and the machine is doing a good job of cutting and forming.
Steel in 18 gauge can be as thick as .050", and I would suspect that attempting to shear 18 on a regular basis could cause problems/damage with flexing and warping or breakage, in a short time, IMO.
There is no burr on the sheared 20 ga steel, so far. I think it might be best to use a wax stick lube on the blades and/or the steel sheet.
There is a notching procedure mentioned in the manual, but I haven't seen where notching is performed yet.
There is a second pair of gears included (presumably for the rolls), surprisingly.
The closest back-to-back bends (dog leg) are about 1/4", but could be closer if the lower V die was releived at the front edge by grinding or milling.
Like any China looky-like a real machine, it appears to need some add-on accessories to improve the accuracy and ease of use. An infeed table/plate with measurement scales for determining locations of cuts and bends seems necessary.
Dial wheels or other indicators for adjusting the parallelism of the rolls, and the amount of deflection for rolling.
Pointers and scales or dial wheels to indicate how far the break blade has traveled, for an idea of the degree of the bend would be very useful.
Without any indicators on the moving parts, excessive wear or damage to the machine's parts might be likely, if the user isn't paying close attention.
The TSC description 3 in 1 combination machine with all the features needed to cut, bend and form metal, wire and rod easily and accurately. 30" effective width. Max shear thickness: 18 ga. Roll diameter: 1 1/2". Shear quickly and precisely - cuts up to 30" x 18 gauge steel. Brake allows for quick, consistent bends. Roll metal smoothly and easily. Wire forming grooves. http://www.tractorsupply.com/welding-metalworking/other-metalworking-tools-accessories/clarke-3-in-1-shear-brake-roll-3805124
The Grizzly G4011 Sheet Metal Machine - 30" ($495) appears to be the same machine, but the G4011 is rated as 22 gauge steel maximum for the break and roll. The maximum steel gauge for the shear is 28. The thinner gauge limits may be more realistic, or just arbitrary numbers picked by someone, or possibly a slightly different machine. http://grizzly.com/products/Sheet-Metal-Machine-30-/G4011
Harbor Freight offers a similar/identical 30" machine with slightly different specs.
On my Central Machinery model I replaced the solid backgauge guide rods and their miserable fragile thumbscrews with 1/2" threaded rods turned to 12mm OD. The threads are slightly undersized so the nuts coast a ways when spun. I set the inside flange width by measuring from the backgauge to the center of the top die on both ends.
The joke of a guide square clamps down a 6" ruler instead. The useless holddown is gone and I use two deep-throat C-clamps and a strip of wood.
I set the shear blades close enough to cut paper, meaning they rub slightly. Even then they may spring apart and fail to cut 1/16" 6061 in the middle. 0.050" Al stock is fine.
I made some thin vee padding strips from flashing for the brake and add them in until the bend angle reaches 90. That's quicker than resetting the die height screws for different thicknesses, and the padding protects the finish better.
Thanks for the tips, Jim. The hold-down bar blocks the view of the shear blades on this model, but works OK. The shear still works without the hold-down, it's just more likely that the material will move as the cut is started. I haven't seen any creeping during the cut yet, but I'm sure it will occur with certain materials or thicknesses.
I expect to try various materials placed in the break V to see how they affect the bend radius. I recall a break (Nick M, maybe), that used urethane in the V.
This model has a truss-type? bar behind the moving shear blade to stiffen the center of the blade, and/or minimize bowing in the center. Hopefully, that will be effective.
I think the key to shear performance and life will be trying to avoid dulling of the blade edges. A stop at Fastenal might yield something better than beeswax. The Lenox synthetic Pro Tool Lube wouldn't be too messy.. it's worked well for any metal cutting I've done. I don't have any machines with enough travel to be able to adapt/improvise a grinder setup for sharpening about 32" of blade edges.
I think you could sharpen them with a hand-held grinder as long as you don't remove any metal from the vertical surfaces or change the angles much. Irregularities that are perpendicular to the cut won't affect its straightness.
Note that the Di-Acro downloaded manuals for machines with this function call it "Brake" not "Break". In particular, I am looking at the front page for the Di-Acro "Number 24 & 36 Finger Brakes".
So -- I would not want one which preferred to "break". :-)
So far mine just bends, mainly when the metal gauge is anywhere near the so-called maximum capacity.
You're right, DoN.. the common usage for these types of machines is brake. I tend to think of the forming procedure as breaking/interrupting a flat plane (instead of braking/stopping a flat plane).
Break Prediction for Chinese equipment. A sudden or marked change. To change direction or discontinue. To give way. To part the surface of. To divide into pieces, as by bending.
Brake A machine for bending and folding sheet metal. A lever or handle on a machine. A variant of break.
Engine or motor? Tomato or ketchup?
On Fri, 27 Nov 2009 01:35:00 -0500, the infamous "Wild_Bill"
Could the bar be drilled to provide visual access while still bring installed? Could one perhaps fabricate and use an acrylic replacement bar? R&R holddown, reinstall on the back of the unit? Add fingers to the bottom of the holddown bar and adjust it upward, to provide visual access beneath?
Thanks for the review, BTW. Well done.
-- Some days, it's not even worth chewing through the restraints.
You can see past it with good lighting, mostly it isn't very effective at keeping the stock from shifting, it's more of a finger guard.
Good lighting and having the machine placed at a good working height (for the height of the operator) are the keys to good visibility, it seems.
A scribed line shows up fairly well even without layout dye, if the lighting is good. A CF lamp on a gooseneck would likely take care of the lighting issue.
A carbide-tip scribed line sparkles clearly, even on new, bare steel. Pencil or sharpie marker lines would be much more difficult to see with the hold-down bar in place.
Some fingers extending downward would allow better visibility, Larry. That would be a good consideration when the other modifications get started.
A bit of a follow-up on the Clarke machine, using 20 ga. .037" steel sheet.
The plates used for the press brake, referred to as Upper Breaking Dies, have very soft edges where the male V is ground on their edges.
After using the brake for some initial forming tasks, which turned out fairly well, I noticed that the edges of the die plates had deformed (feels like a severe rolled-over wire edge).
This appears to be the China-made gotcha. The plates have an overall appearance of being surface ground, which is generally done on many visible parts to make the Chinese machines look better, but the alloy seems to be mild steel (or worse, if they're cast iron plates, which I've seen on other types of machines from China, very smooth but painted). The tapered edges have a ground finish from a more coarse abrasive, more like a blanchard grind.
I'll most likely need to file them to restore the edges on them, and perform an adjustment of the 6 sections before we continue using the brake.
I think the plates are ground so they fit the clamp at the top identically and thus line up at the bottom. They wouldn't if they were just left sheared.
Do you really need the chisel edge? I radiused the edges on mine with a file so bends are less likely to crack.
You're correct Jim, a sharp edge isn't needed, but the edges are badly deformed, and definitely need dressed up a bit.. a small radius would probably be ideal, as you suggest.
I just hadn't anticipated that the edges would be so soft.
On Sun, 29 Nov 2009 14:06:15 -0500, "Wild_Bill"
After you clean them up (with a nice radius)...you might want to think about treating them with Kasite...caseharding them.
"Aren't cats Libertarian? They just want to be left alone. I think our dog is a Democrat, as he is always looking for a handout" Unknown Usnet Poster
Heh, heh, I'm pretty sure my dog is a liberal - he has no balls. Keyton
On Sun, 29 Nov 2009 03:14:19 -0500, the infamous "Wild_Bill"
Bummer, but sorta expected, oui?
Heat/quench adjustment? (Unless they're CI)
-- Some days, it's not even worth chewing through the restraints.
Do you have the means to grind them all to size and shape after hardening? Perhaps an angle plate on a surface grinder? If not I would avoid heating and hardening them since the bottom edges won't line up if they warp at all. Those machines already depend too much on fair weather and good Kharma when you attempt to set them up.
Like Jim suggests, warpage would be a definite problem. Most any process using a lot of heat, flame or arc would likely result in warping.
I suppose there is another upgrade approach, maybe using a better grade of steel for the press plates.