18" Bending Brake - one not very expensive tool

[kagliostro]

18" Bending Brake



$ 37.99

here

http://www.harborfreight.com/18-inch-bending-brake-39103.html


http://s373.photobucket.com/albums/oo176/gwtekman/Chassis%20Bending/

for the more enterprising

http://www.majorleagueduning.com/tech/Brake/brake1.htm

Kagliostro

[jjasilli]

Seems useful.  Here's a couple of reviews:  Harbor Freight Review -- 18" Bending Brake

Harbor Freight 18" bending brake review

Note that at the very end of the 2nd site, the reviewer points out that it cannot make a box.  I suspect that shorter bending beam could correct that, so long as it could be clamped.  Maybe the handle holders could be drilled and tapped for set screws to hold the handles in place.

[Boots Deville]

I have the next model up from them.  I've bent a bunch of chassis with it.  I jones for a nicer one, but in the meantime the Harbor Freight one does the job.

[Willabe]

How do you make ends for the chassis, or do you just go with a channel type chassis?


             Brad     

[Boots Deville]

Instead of the metal bar on top I cut a piece of 3/4" ply to the length of the inside dimension of the chassis and then run that thru the table saw with the blade at a 7-degree angle so I can "over-bend" to get the 90 degree result.  It's a poor-man's finger brake, but it's one of those things where you do it enough, you pick up tricks, it gets easier and the results get better.

I've posted this before, but drilling the front and rear panels in flat stock before bending is *so* much nicer, IMO.

Edit:
Here's a link to a photo album for two Blackface builds I'm currently working on.  It shows the cut, drilled aluminum prior to bending, but not that actual bending process.
https://picasaweb.google.com/haasamps/RubyDeluxeOldeSchoolAB763?authuser=0&authkey=Gv1sRgCPf_3I3bsfHUWg&feat=directlink

[Willabe]

Instead of the metal bar on top I cut a piece of 3/4" ply to the length of the inside dimension of the chassis and then run that thru the table saw with the blade at a 7-degree angle so I can "over-bend" to get the 90 degree result.  It's a poor-man's finger brake, but it's one of those things where you do it enough, you pick up tricks, it gets easier and the results get better.

I belive it, thanks.

I've posted this before, but drilling the front and rear panels in flat stock before bending is *so* much nicer, IMO.

I belive this too. After drilling out a few blank chassis, I found a lot of play in them. Even with welded corners and clamping the chassis to a tall solid back fence and using clamped wood blocks, all a pain. It slows you down so much. I want to get some of those lever action jig clamps, (very fast action) and build a clamping jig or two for this that would bolt to the T slots in the drill press table. Should be a 100 times faster.    

Thanks for the tips.


             Brad      

[kagliostro]

One guy has build this



http://digilander.libero.it/pieffe43/pressa.htm

Kagliostro

[overtone]

that is great. I did not get the adjustable fence part yet. Need another coffee...
thanks for posting that
best, tony

[kagliostro]

A file with some interesting ideas

http://homepage.ntlworld.com/ruperthirst/Recent%20DIY%20Projects/Audio%20Projects/Audio%20Projects%20Core/GainClone/Onixia%20Gainclone/Bending%20Aluminium.pdf

Kagliostro

[kagliostro]

A Very functional homemade brake project with good documentation

http://studebakercarclubnsw.com/pdf/panbrake.pdf

Kagliostro

[stingray_65]

the Grizzly 24" box pan brake

http://www.grizzly.com/products/24-Box-and-Pan-Brake/G0557

I own it and LOVE it.

If I bend the sides of the chassis first, I can brake the full width of 24".

I'll pan brake a 19 1/2 x 8 x 2" chassis this week on it for my new 6V6 TOS project.

I routinely bend 18 ga steel even thought its rated for 20. but I also allow for a larger bend radius of 2.5x material thickness. I've bent 16 ga steel, but at about 10" width and a 3x material thickness bend radius.

As far as this weekends folding, 14 ga 5052 aluminum and 5x bend radius. 5052 has a strong grain to it and brakes nicely with the grain, but has a LOT of resistance cross grain so 5x is the smallest bend radius I'll even try.

I figure I save about $15-20 each chassis, so that means I have to build maybe 20 - 30 chassis to pay for itself, but I have so many more chassis choices, and odd brackets I might need are just a piece of scrap and a few folds away.

Ray

[Boots Deville]

Hey Ray, would you might sharing a picture or two of a chassis you've bent?

I have a harbor freight brake, and it's worked fine for many .060" aluminum chassis, but the bends are quite as sharp (small radius) as I'd like.  Also, I have to improvise a box brake by cutting "fingers" out of scrap wood.  I would consider upgrading to the Grizzly if I could be sure I'd get a smaller radius bend out of it. 

-John

[stingray_65]

Hey Ray, would you might sharing a picture or two of a chassis you've bent?

I have a harbor freight brake, and it's worked fine for many .060" aluminum chassis, but the bends are quite as sharp (small radius) as I'd like.  Also, I have to improvise a box brake by cutting "fingers" out of scrap wood.  I would consider upgrading to the Grizzly if I could be sure I'd get a smaller radius bend out of it. 

-John

I will do that
Just so you know, the Grizzly is adjustable, I can change the distance from the fingers to the bend line.

As kinda mentioned in my post, certain materials bend differently, the minimum bend radius for different materials is expressed in multiples of material thickness.

So basically, I have a few scraps of whatever I'm braking, and use them as a setup gauge between my fingers and the brake line. so If I'm bending .040" material, and the machinery's handbook says 3x. I stack 3 .040 pieces up against the fold line and bring the fingers up to the stack.

Short and sweet it will bend as sharp a corner as the material allows.

To get real sharp corners, you want a press brake. It can actually form the corner material into the die. However I've only seen hydraulic units do this, near impossible I imagine for hand powered brakes.

sheet metal forming is kind of an exacting skill. to get the best results you need charts and need to know your materials.

For example, lets say you have a piece of metal 2" wide, you scribe a line at 1" down the center. one would expect that you would have  2 legs that are 1" right?

What you would have is 1 leg at 1" and the other is 1 1/16" !!!

The radius! it cuts around the corner! your material didn't stretch!
so you would use a 1 15/16" wide piece, scribe the 1" hold the correct side under the fingers and THEN you get 2 1" legs !!! weird huh!

But there is a TON of literature out there, guys have been folding up boxes for years.

I'll post pics Saturday afternoon if I don't work, otherwise Sunday night

Ray

[kagliostro]

Interesting explanations Ray

thanks

Franco

[Boots Deville]

Thanks Ray, very useful information.  When I got my brake, I was mildly disappointed that I couldn't get bends as nice as on the Hammond chassis I used before.  Maybe those were done on a press brake.

I've attached a picture of a chassis that I recently bent out of .060" aluminum.  You can see the bend along the left hand side.  It's not horrible, just not as small of a radius as you'd see on a Hammond.

Thanks again...

-John

[stingray_65]

sorry about the pic quality, I forgot my camera and a buddy shot these with his cell phone.

As you can see the inside radius is very tight. I bent these with the fingers at 1.5 x's material thicness away from the bend line.

the inside radius is in compression and the outside radius is being stretched.

Oh! the material is 14 ga .0641" so the bend radius is .097", give or take. it is tighter than 1/8"r.

[Boots Deville]

That meets or exceeds my stringent quality standards. 

Seriously though, that looks great Ray, thanks for taking the time to post those.  I'm sold.

[stingray_65]

I have to say it's not for every one. but it can pay for itself over time.

Making parts from sheet metal has always been a part of my job, every shop I've worked either had a Pexto or Tennsmith and could work 12ga steel.

This little brake has all the features of those Pexto and Tennsmiths and is about perfect for a serious amp builder who doesn't have access to a quality chassis builder.

I will say, it takes some practice to master, but there are TONS of things to practice on.

Stop and pick up those old microwaves, washers and driers. Make drawer dividers for your tool box, bins for parts. Heck I've even made shipping boxes, Big cardboard boxes can be made into lots of little boxes with some glue, just dont clamp the cardboard, it crushes.

There is a copy of the machinery's handbook in PDF online. It is probably the most indispensable tool in a shop. They can also be bought on Ebay for a 20 or less sometimes.

There is more information in that book on fabrication and specs for just about anything you can imagine, I've even found a chapter on specs for screws that don't exist, but should they be made they have the guidelines all ready for machining them.

The problem with the Machiney's handbook though is finding things in it, There is actually a companion book for it on how to look things up in it.

This book is so important, if you have ever seen a machinists top tool box, it has a large drawer in the top middle. This drawer is designed so the handbook fits neatly inside and nothing else.

[jjasilli]

Good stuff, Ray.   

[Willabe]

Hi Ray,

How are you cutting your sheet stock to size? Also how do you cut the corner notches, including the little relief hole in the inside corner of the notch?

Is that just a hole drilled in that corner before you cut the notch out?


                     Brad     

[stingray_65]

Hi Ray,

How are you cutting your sheet stock to size? Also how do you cut the corner notches, including the little relief hole in the inside corner of the notch?

Is that just a hole drilled in that corner before you cut the notch out?


                     Brad     

YUP.

drill the hole about 4X the material thickness, so in this case .064 x 4 = .256 so 1/4" is good. The drilled hole isn't necessarily needed, but things get funny in corners and this eliminates having to figure things out.

I cut the notches (the whole sheet really) on my table saw. Just about any powered wood working tool with carbide will cut aluminum nicely. wear ear protection. REALLY wear ear protection! when doing this.

I've cut 1 3/4" thick aluminum plate at work with a beat up black and decker skill saw with a mediocre blade and good cutting fluid and had very nice results.

Ray

[jjasilli]

I've cut sheet aluminum on my table saw using a brown cut-off wheel about 1/8" thick.  I'm getting heavy burring on the underside of the aluminum sheet.  Is there a better way?

[Boots Deville]

I've been using a jig saw up 'til now.  I have trouble getting a perfectly straight edge with it, so I cut it a little proud and use a router with a straight bit along a straight edge to get a nicely finished straight cut. 

I'm reluctant to try it on my table saw with my "good" blade in it, and I don't have a mediocre one to put in it, so I think I'll try the Skil saw route the next time.

Thanks for the tips Ray!

-John

[jjasilli]

Due to lack of knowledge, I've been reluctant to use a router bit on metal.  Any special type of bit to suggest?

[Willabe]

Due to lack of knowledge, I've been reluctant to use a router bit on metal.  Any special type of bit to suggest?

There's a video on you tube that shows a guy cutting out an opening for an IEC socket in an aluminum chassis. He made a template, clamped it on and cut the opening with a router using a small diameter carbide bit. Came out perfect.

I like the spiral type of router bits.

Wear eye protection.


                          Brad

[jjasilli]

Thanks, Willabe.  Now that you mention that, it made me remember another site I saw awhile back, where a guy used a template for a router to finish a large hole in a chassis for a tranny.

[PRR]

> reluctant to use a router bit on metal.

There's two kinds of "metal". For most purposes: Iron and Aluminum.

Leave iron/steel to the Iron workers.

Aluminum can usually be cut with woodworking tools and techniques.

[DummyLoad]

my CNC machine uses a porter-cable wood router for the mill-head and i use mill bits for cutting non-ferrous metals. for a while, until i found other sources for tooling, i used porter-cable 1/8" wood bits to cut .125" aluminium. they are/were the only brand of wood bits that would hold up to machining aluminum.

--DL

[Boots Deville]

Ray, can you tell us what the maximum box depth is with the Grizzly?  They don't specify that anywhere I've seen, but the Shop Fox M1101 (see Amazon) looks almost identical (except for the color) and they specify a 1-3/4" maximum box depth, and I'd like to make sure the Grizzly can handle 2".

[G._Hoffman]

Any good quality carbide tipped router bit should do fine on aluminum.  You don't even need to adjust the cutting speed, though the feed rate should go down a bit.  Freud, Whiteside, etc. are all good.  If it seems too cheap to be good, it probably is, but most router bits are fine.  If you can afford them, end mills are much better than straight bits.  Upcut bits clear chips better, but downcut bits leave a cleaner edge.  Both have their places, but they get really expensive pretty damn quick because they are solid carbide.  Also, they can be a bit fragile for plunge cuts, so don't plunge too quickly.


Gabriel

[stingray_65]

Ray, can you tell us what the maximum box depth is with the Grizzly?  They don't specify that anywhere I've seen, but the Shop Fox M1101 (see Amazon) looks almost identical (except for the color) and they specify a 1-3/4" maximum box depth, and I'd like to make sure the Grizzly can handle 2".

I'll double check this week. What they mean by max depth is how far the fingers rise.

True max depth can be much more, but it may involve pulling the fingers (which is real easy, loosen an allen screw)

The box pictured is a full 2", but I bent from the edges in, I did have the fingers off on the sides.

I have not seen a Fox personally, but I believe it to be the same unit.

Woodward fab makes a brake in this same class.

Link here to see what I mean about bending from the outside in and cheating max depth limits

http://www.photoshop.com/users/kimwieas/assets/9afb514a2c00491b820bfc91b159d02c?movie=48

[G._Hoffman]

The note about the eye glasses.  If you grind, router, and metal use the glasses.  And watch out for the chips.  I had a chip lodge in a knuckle joint, Didn't see a doctor, it took months for the chip to work to surface so I could remove with a pair of needlenose (chainlink to the diehards).  

You don't want to compromise your eyesight

Absolutely.  But the most important safety device you have is your mind.  NEVER use any tool unless you understand how it works, what can go wrong, what will happen when it goes wrong, and how to protect yourself when it does.  Don't stand in the line of fire for kickback off the table saw, and don't put your hands where they can be sucked in by a self-feeding router bit.  Think every job through, every time, and keep yourself out of harms way.  And if you aren't sure, ask for help.  

Oh, and don't wear loose clothing, jewelry, or long sleeves around power tools!


Gabriel

[Boots Deville]

I'll double check this week. What they mean by max depth is how far the fingers rise.

True max depth can be much more, but it may involve pulling the fingers (which is real easy, loosen an allen screw)

The box pictured is a full 2", but I bent from the edges in, I did have the fingers off on the sides.

I have not seen a Fox personally, but I believe it to be the same unit.

Woodward fab makes a brake in this same class.

Link here to see what I mean about bending from the outside in and cheating max depth limits

http://www.photoshop.com/users/kimwieas/assets/9afb514a2c00491b820bfc91b159d02c?movie=48

Thanks Ray, that's good information.

See this video where the author runs into trouble bending 3" sides on the Grizzly brake (skip ahead to the 7:00 mark)
Sheet Metal Box & Pan Brake Tutorial - Grizzly Brake in my home shop

But if you say the unit will bend 2" sides that's good enough for me. 

After a little more web surfing, I'm pretty sure the Shop Fox and the Grizzly are the same unit with both companies being under the "Woodstock International" umbrella.  Grizzly is the direct to customer side and Shop Fox distributes to retailers.  I stopped in a local retailer yesterday who carries Shop Fox and they said they could get that brake for me for $260.  If I waited until they were ready to place an order I wouldn't have to pay freight charges.  A week or two wait - no big deal.

So if the brake will handle two inch sides, I think I'm going to pull the trigger.

Thanks again for your help with this.

-John

[Willabe]

That guy is bare foot.     

I know he's got a shop vac on the band saw but none of them are perfect. Metal slivers in the bottom of your foot? Or drop a piece of sheet metal on a bare foot?

                       NO, NO, NO!



                                     Brad     

[Boots Deville]

Yeah, if you read the comments on the video, the majority are about it being a bad example of safe working practices.  Bare foot, no eye protection, etc.

[Willabe]

One of the videos (for the Fox?) has the guy showing how the whole top carriage can be adjust backwards. I wonder if you could move that top carriage back to get more distance from the bend "point" on the machine, which would allow more distance for the box to travel before hitting the top face of the fingers. You could then use, say a 1/4" piece of flat mild steel that's 2", 3" wide as a straight edge/clamping caul between the bottom of the fingers and the brakes table to move the bend point back to the brakes pivot point?

The clamping caul would have to have it's front edge at the same angle as the top/flat face of the fingers though. This way you could get a nice tight, sharp corner with the extra depth you might need. You might have to start the bend in the normal way, then finish it with the straight edge/clamping caul, but maybe not?
 
I bet it would work.


                          Brad            

[Boots Deville]

Yeah, that would probably work, but the clamping caul would ideally be the same length as the sum of the fingers you're using.  So then you get in a situation where you need a different length caul for each length chassis you bend.  That's where I'm at now with the brake I have in the style of the one pictured at the top of this thread.  Since it's not a finger brake, for the long sides I cut scrap 2x4 to the correct length and clamp the workpiece down with that.  I works, but it's not ideal.

If the unit can handle 2" sides without any such compromises, then I would be happy with it.

[gmoon]

I picked up one of the 30" brakes at Harbor Freight this weekend, for a little over $50 (with a 20% coupon). I figured with the coupon I might as well go for the bigger one...

It's a little different than the smaller unit. The back of the brake is reinforced with an angle, forming a box shape. It's not welded entirely along either seam, though. The welds are approx 1" for every 5 inches.

One more difference between the 30" one and the review videos--the handles are threaded, and they do screw securely into place, rather than just slotting loose. Maybe it's a new overall design change, maybe it's just the 30" model.

Those box brake/sheer/etc. combo jobs sure look nice. Maybe someday down the line...

[Boots Deville]

One more difference between the 30" one and the review videos--the handles are threaded, and they do screw securely into place, rather than just slotting loose. Maybe it's a new overall design change, maybe it's just the 30" model.

Must be a design change.  I got the Harbor Freight 30" break a two or three years ago and the handles slide in and out - not threaded.

[gmoon]

I have to go back to HF for a return  , so I'll check out the 18" brakes for the same change...

[gmoon]

OK, at our Harbor Freight showroom (S. Akron, OH), the 18" brake still has the slide-in handles, and the 30" brake has larger-diameter, threaded handles.