Vise Mounted Metal Finger Brake Question

[Susan_in_SF]

Hi guys,
As many of you already know, I have a 1 car garage that is stuffed with woodworking and metalworking equipment. So, I have been looking for ways to save space, lol.

I have found, on a couple of different websites, a nifty space saving gadget. It is a finger brake that is mounted onto your vise. What I like about it is that you can bend metal that is longer than the vise jaw width if you just bend one section then scoot it to the next section to bend, etc.

I read off of one instruction manual to never use the finger brake on vise jaws that are smaller than the brake length.

I found one site selling a vise mounted finger brake that is 8 inches wide. My widest machinist vise's jaws are 5 inches. However, I also have an old Columbian woodworking vise (mounts on underside of bench) that has 10 wide jaws. It's pretty heavy duty, and weighs 33 lbs. Plus, being a woodworking vise, it's got a much deeper "throat" than my 5" bullet vise (if it matters, my 5" is around 95 lbs, I think).

If you look at examples of this vise finger brake bending sheet metal, it looks like the advantage of having a deeper vise throat is that the bend can be made further from the edge, if the vise has room, but I could be wrong.


In advance, sorry for all these questions

***Do you guys think a woodworking vise would be just as effective as a mechanics/machinists with these vise finger brakes?**

**Do you think, based on the design of the finger brake, that a deeper throat depth has limited advantages with a 90 degree bend**

**If you had to choose, would you use the 10" Columbian woodworking vise, or the 5" Wilton bullet vise?**

I would primarily use such a finger brake for making enclosure boxes for my various motor control chassis' and for the control box that would have the on/off switch, speed display, etc. Here is a pic of one model chassis I plan on using with a treadmill motor:

It would also be nice to have something heavy duty in case I need to bend something thicker than sheet metal, but space is an issue.

Here are links to a couple of sites selling such gadgets:

https://www.princessauto.com/en/detail/8-in-vise-mount-bending-brake/A-p8663775e

https://www.eastwood.com/eastwood-6-inch-vise-press-brake.html

Thank you!
Susan

 

[RJSakowski]

I wouldn't think that a woodworking would hold up as well as a machinist's vise. They are not intended for that kind of force.

Regarding the vise mounted brake, there are some limitations. You are limited to the height if the sides by the depth of the jaws of the vise. Also, when bending longer pieces, you will get deformation from the regions outside the brake. You can compensate somewhat by making a partial bend and advancing the work until the entire piece has partially bent and the bending a little moreby repeating the process until you have bent to the 90º angle. It is fairly well limited to making 90º bends as well.

Back some forty years ago, I made a brake similar to this.
https://books.google.com/books?id=u...AEIKjAA#v=onepage&q=sheet metal brake&f=false
I used it for making hundreds of electronic enclosures out of .063" aluminum and had bent up 1/8" aluminum sheet and 1/8" x 1" HR steel and .026 stainless steel. I used white oak for the wooden parts. I still use that brake.

 

[pstemari]

Palmgren also makes a somewhat bigger version that only uses the vise for support, and gets its bending force from a lever. I've got that one and I'm pretty happy with it. It will go about a foot wide.

Sent from my Pixel XL using Tapatalk

 

[hman]

I have two such finger brakes that I bought from Grizzly :
http://www.grizzly.com/products/Grizzly-6-Vise-Brake/H3245
Both are the 6" size, and I've used them on both a 5" and 6" vise. Love 'em!

***Do you guys think a woodworking vise would be just as effective as a mechanics/machinists with these vise finger brakes?**
I'll agree with previous posters. Don't think a woodworking vise is strong enough. Look at the bars that hold the moveable jaw and compare them to the bar of a metalworking vise. Plus, they're further from the top of the vise, and will experience that much more "adverse leverage."

**Do you think, based on the design of the finger brake, that a deeper throat depth has limited advantages with a 90 degree bend**
Both throat depth and jaw "overhang" will affect how long the "inside" leg can be.

**If you had to choose, would you use the 10" Columbian woodworking vise, or the 5" Wilton bullet vise?**
I'd use the Wilton ... unless I were bending very thin aluminum or even thinner steel.

Couple other observations -
(1) Note that the brake in your second photo doesn't have removable fingers. So it would be less versatile that the Grizzly or the one in your first photo (ie, not a "box brake")
(2) Regarding "I read off of one instruction manual to never use the finger brake on vise jaws that are smaller than the brake length," I'd guess that was because the castings of the brake aren't designed to take the bending forces developed when not supported by the vise jaws. You might possibly improve the situation by placing a steel bar (say ¾" square) between the vise jaw and the brake casting. You'd lose the nice magnetic hold-it-in-place feature of the brake, but would gain support. I've not had any problems using the 6" Grizzly on my 5" vise, but that's a lot smaller mismatch than 5" to 8"

PS - Just for fun, could you please post a link to the site where you found the 8" brake? Thanks!

 

[C-Bag]

Personally I wouldn't use either vise. The pic demonstrates why as it can't even bend 90deg. The throat is just too small IMHO. And because of the screw of the vise it's slow, and tough to hold a piece against gravity, all while you are trying to maneuver the vise. You could make a similar setup for your arbor press and be way ahead. I made one with square tubing to go over the ram to hold straight piece with angle iron welded to a plate for the receiver, anvil, bottom piece, whatever it's called. For larger projects I have a HF 30" 3in1 that takes up some room and isn't light but it's 3 functions in one machine(if it was made right and adjusted right) shear, brake and roller. Not perfect but does a way better job than the years of messin' with a vise.

 

[hman]

Agreed that it's not the easiest tool in the shop. But it's actually not too bad.

(1) Mark fold line on sheet metal
(2) LIGHTLY close press jaws on part, just enough to keep it from falling out
(3) Reposition the part as needed to put the fold line where it should be. You can use a machinist's square to align the edge of the part perpendicular to the press fingers.
(4) Slowly close the vise, keeping an eye on how close the fold is to 90º. As with ANY bending press, go just a bit beyond 90º to allow for spring-back.
(5) Release part from vise jaws. Check fold for squareness. If it's under 90º, it's pretty easy to replace/realign in the tool by holding the fold against the fingers. If over, you can unbend it a little by hand.

And yes, it's perfectly capable of making a 90º bend. There's just some limit as to how long the "inside" leg can be. Deep boxes would be difficult, but not shallow ones.

 

[BGHansen]

Agreed that it's not the easiest tool in the shop. But it's actually not too bad.

(1) Mark fold line on sheet metal
(2) LIGHTLY close press jaws on part, just enough to keep it from falling out
(3) Reposition the part as needed to put the fold line where it should be. You can use a machinist's square to align the edge of the part perpendicular to the press fingers.
(4) Slowly close the vise, keeping an eye on how close the fold is to 90º. As with ANY bending press, go just a bit beyond 90º to allow for spring-back.
(5) Release part from vise jaws. Check fold for squareness. If it's under 90º, it's pretty easy to replace/realign in the tool by holding the fold against the fingers. If over, you can unbend it a little by hand.

And yes, it's perfectly capable of making a 90º bend. There's just some limit as to how long the "inside" leg can be. Deep boxes would be difficult, but not shallow ones.

Hi John,

First off, good advise for the OP. Actual use "in the field" instead of opinion. Not that opinion's don't matter, but actual experience is the proof in the pudding.

Curious how you hold to a scribed line. Do you magnet a straight edge or something at an offset to your line and let that set on the blade? I've got a 3-in-one sheet metal machine and the press brake has always been a challenge to hit the line. The bottom anvil doesn't have a large footprint so the stock wants to move. Especially with the bottom anvil moving up to the stationery blades while turning the crank. I've thought about making an extension table to better support the stock, but have the luxury of a 24" DiAcro finger brake also. Using my 3-in-one machine makes me wish I had a third arm.

I guess on 2nd thought with a footprint 6" wide, you're probably able to hold the stock in one hand for positioning and turn the vise with the other. Just curious.

Bruce

 

[Susan_in_SF]

I have two such finger brakes that I bought from Grizzly :
http://www.grizzly.com/products/Grizzly-6-Vise-Brake/H3245
Both are the 6" size, and I've used them on both a 5" and 6" vise. Love 'em!

***Do you guys think a woodworking vise would be just as effective as a mechanics/machinists with these vise finger brakes?**
I'll agree with previous posters. Don't think a woodworking vise is strong enough. Look at the bars that hold the moveable jaw and compare them to the bar of a metalworking vise. Plus, they're further from the top of the vise, and will experience that much more "adverse leverage."

**Do you think, based on the design of the finger brake, that a deeper throat depth has limited advantages with a 90 degree bend**
Both throat depth and jaw "overhang" will affect how long the "inside" leg can be.

**If you had to choose, would you use the 10" Columbian woodworking vise, or the 5" Wilton bullet vise?**
I'd use the Wilton ... unless I were bending very thin aluminum or even thinner steel.

Couple other observations -
(1) Note that the brake in your second photo doesn't have removable fingers. So it would be less versatile that the Grizzly or the one in your first photo (ie, not a "box brake")
(2) Regarding "I read off of one instruction manual to never use the finger brake on vise jaws that are smaller than the brake length," I'd guess that was because the castings of the brake aren't designed to take the bending forces developed when not supported by the vise jaws. You might possibly improve the situation by placing a steel bar (say ¾" square) between the vise jaw and the brake casting. You'd lose the nice magnetic hold-it-in-place feature of the brake, but would gain support. I've not had any problems using the 6" Grizzly on my 5" vise, but that's a lot smaller mismatch than 5" to 8"

PS - Just for fun, could you please post a link to the site where you found the 8" brake? Thanks!

Hi Hman,
Thanks for your feedback. Here is the link for the 8"
https://www.princessauto.com/en/detail/8-in-vise-mount-bending-brake/A-p8663775e
Susan

 

[hman]

I guess on 2nd thought with a footprint 6" wide, you're probably able to hold the stock in one hand for positioning and turn the vise with the other. Just curious.

Yup. That's what I do. Stock that size is easy to hold while lightly closing the vise. Then (per step 2) I let the light pressure of the bending jaws hold the part as I adjust its position prior to folding.

I've not tried folding wide parts in segments, as Susan_in_SF was talking about doing. Might be bit tricky if it gets too big or heavy.

Thanks, Susan, for the link! Looks sturdy enough to do the job.

 

[Susan_in_SF]

Yup. That's what I do. Stock that size is easy to hold while lightly closing the vise. Then (per step 2) I let the light pressure of the bending jaws hold the part as I adjust its position prior to folding.

I've not tried folding wide parts in segments, as Susan_in_SF was talking about doing. Might be bit tricky if it gets too big or heavy.

Thanks, Susan, for the link! Looks sturdy enough to do the job.

The idea of using an 8" vise pan brake attachment sounds great, but how many of us have a bench vise with 8 inch wide jaws??
Susan