Clarke Shear Break Roll 30" Sheetmetal Machine Brake 3in1 Grizzly HF

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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.

--
WB
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Re: Clarke Shear Break Roll 30" Sheetmetal Machine Brake 3in1 Grizzly HF


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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.

jsw

Re: Clarke Shear Break Roll 30" Sheetmetal Machine Brake 3in1 Grizzly HF


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.

--
WB
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Re: Clarke Shear Break Roll 30" Sheetmetal Machine Brake 3in1 Grizzly HF


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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.

jsw

Re: Clarke Shear Break Roll 30" Sheetmetal Machine Brake 3in1 Grizzly HF



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    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". :-)

    Enjoy,
        DoN.

--
    (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
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Re: Clarke Shear Break Roll 30" Sheetmetal Machine Brake 3in1 Grizzly HF


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So far mine just bends, mainly when the metal gauge is anywhere near
the so-called maximum capacity.

jsw

Re: Clarke Shear Break Roll 30" Sheetmetal Machine Brake 3in1 Grizzly HF


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?

--
WB
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Re: Clarke Shear Break Roll 30" Sheetmetal Machine Brake 3in1 Grizzly HF


On Fri, 27 Nov 2009 01:35:00 -0500, the infamous "Wild_Bill"

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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.

Re: Clarke Shear Break Roll 30" Sheetmetal Machine Brake 3in1 Grizzly HF


wrote:
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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.

jsw

Re: Clarke Shear Break Roll 30" Sheetmetal Machine Brake 3in1 Grizzly HF


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.

--
WB
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Re: Clarke BAD NEWS Shear Break Roll 30" Sheetmetal Machine Brake 3in1 Grizzly HF


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.

--
WB
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Re: Clarke BAD NEWS Shear Break Roll 30" Sheetmetal Machine Brake 3in1 Grizzly HF


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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.

jsw

Re: Clarke BAD NEWS Shear Break Roll 30" Sheetmetal Machine Brake 3in1 Grizzly HF


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.

--
WB
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Re: Clarke BAD NEWS Shear Break Roll 30" Sheetmetal Machine Brake 3in1 Grizzly HF


On Sun, 29 Nov 2009 14:06:15 -0500, "Wild_Bill"

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After you clean them up (with a nice radius)...you might want to think
about treating them with Kasite...caseharding them.

Gunner

"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

Re: Clarke BAD NEWS Shear Break Roll 30" Sheetmetal Machine Brake 3in1 Grizzly HF


On Sun, 29 Nov 2009 03:14:19 -0500, the infamous "Wild_Bill"

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Bummer, but sorta expected, oui?


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Heat/quench adjustment?  (Unless they're CI)

--
Some days, it's not even worth chewing through the restraints.

Re: Clarke BAD NEWS Shear Break Roll 30" Sheetmetal Machine Brake 3in1 Grizzly HF


wrote:
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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.

jsw

Re: Clarke BAD NEWS Shear Break Roll 30" Sheetmetal Machine Brake 3in1 Grizzly HF


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.

--
WB
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