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Post subject:adjusting a Chicago brake
 Posted: Jun 05, 2008 - 05:06 AM #7624
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Joined: Apr 12, 2007
Posts: 4
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I recently acquired a 36" Chicago finger brake, rated at 16 ga., possibly 50 yrs. old and in good shape. I folded some pieces of .050" aluminum, and noticed that the clearance in front of the fingers was barely enough. I looked the machine over, and to my astonishment there is no way to adjust the position of the fingers behind the bend line.
The machines I have used have been benchtop DiAcro brakes and an older 48" finger brake, American made. Those all had adjusting screws: one on either side for forward/back finger position, and another pair on top for setting the clamp action to cam over properly for the material thickness.
This brake seemed like a fine machine to me, made well and weighing maybe 600-700 lbs. with the stand. So why is it set to do 16 ga. and only 16 ga.?
I am also not too happy with the clamp action. I can adjust the spring pressure, but I'm getting minimal cam-over effect at the end of the lever stroke, so that the lever creeps back up if I don't hold it as I make the bend. I'm not seeing any adjustment option except for spring pressure.
Anyone have one of these?
John |
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Post subject:RE: adjusting a Chicago brake
Posted: Jun 06, 2008 - 02:45 AM #7626
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Power User
Joined: May 16, 2005
Posts: 178
Location: Atlantic, Iowa
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How about a picture of that baby to help us understand .  |
_________________
Stickman,
The thin tinman.
www.martinsheetmetal.com
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Post subject:RE: adjusting a Chicago brake
Posted: Jun 08, 2008 - 11:49 PM #7629
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Joined: Apr 12, 2007
Posts: 4
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These photos show the back and front of the left side, then a view of the clamp lever. You can see the vertical springs with the nuts to adjust the pressure. The clamp lever can be set to a different orientation, but since it's held with one setscrew it is clearly not meant to be an everyday adjustment. I've fiddled with that orientation, never quite getting what I expect. What I want is that cam-over effect that you get with correctly adjusted vise grips - you apply compression, then it relaxes slightly and snaps to a stable position.
thanks
John |
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Post subject:RE: adjusting a Chicago brake
Posted: Jun 09, 2008 - 01:22 PM #7633
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Power User
Joined: May 16, 2005
Posts: 178
Location: Atlantic, Iowa
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| I now understand your problem and thanks for posting the pictures. I also am amazed that there is no adjustment for that. Chicago equipment was always rock solid and that brake does look like a nice pc of equipment. When you say only 16 ga ?? What happens on lighter stuff...26 ga. for example. Hopefully someone here can help you that has used one of them. |
_________________
Stickman,
The thin tinman.
www.martinsheetmetal.com
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Post subject:RE: adjusting a Chicago brake
Posted: Jun 09, 2008 - 07:58 PM #7636
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Joined: Nov 27, 2006
Posts: 28
Location: Omaha, NE
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Morton,
What is the model and serial number of the brake? |
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Post subject:RE: adjusting a Chicago brake
Posted: Jun 10, 2008 - 04:07 AM #7638
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Joined: Apr 12, 2007
Posts: 4
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Gladwin-Omaha wrote:
Morton,
What is the model and serial number of the brake? Model BB-316, Ser. #304410
Stickman, the thinner the material, the greater the bend radius. I prefer to use decimal inches, so: 16 ga. steel is .060", 16 ga. brass is .050". I'd say the clearance from finger to bend line is about .050". When I fold .050" material, I get an inside radius of about 3/64". For .032" material it's around 1/16". (I haven't tried thinner, there's none in the shop right now.) Strictly speaking, the fold takes on an asymmetrical shape with thin sheet, because it's being pushed up from a distance behind the clamp line and has a gradual curve. The difference may seem small, but I find it very noticeable, not at all what I want.
John |
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Post subject:RE: adjusting a Chicago brake
Posted: Jun 10, 2008 - 09:10 PM #7643
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Joined: Nov 27, 2006
Posts: 28
Location: Omaha, NE
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Morton,
This brake can be adjusted. 
However, this brake is obsolete and no parts can be ordered from the factory. 
But I do have the manual with all the adjustment steps, parts list and specs. The file is too large to be attached in this message. PM me your email address and I will send it to you.
Thanks.
Chad |
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Post subject:RE: adjusting a Chicago brake
Posted: Jun 10, 2008 - 11:51 PM #7644
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Webmaster
Joined: May 13, 2003
Posts: 1327
Location: Waukesha
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| Can I get a copy as well I'll be more then happy to add it to the library for all to use |
_________________
"If you make your job important it is quite likely to return the favor" Author Unknown
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Post subject:RE: adjusting a Chicago brake
Posted: Jun 11, 2008 - 01:19 AM #7645
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Joined: Apr 12, 2007
Posts: 4
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Thanks, the help is much appreciated!
John |
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Post subject:RE: adjusting a Chicago brake
Posted: Jun 11, 2008 - 02:33 AM #7647
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Power User
Joined: Nov 01, 2006
Posts: 95
Location: McEwen,Tn.
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Morton........Have you tried clamping your metal and then adjusting the spring ? As for the forward and backward movement of the top part, maybe an eccentric pivot point that as it's turned will adjust to & fro..My 4 ft. Tennsmith is adjusted that way.
Could be that you have to shim those teeth..They are removable aren't they??
bordontn2 |
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"Old too soon/ smart too late"
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Post subject:RE: adjusting a Chicago brake
Posted: Jun 16, 2008 - 06:05 PM #7675
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Webmaster
Joined: May 13, 2003
Posts: 1327
Location: Waukesha
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Thanks to Chad of Gladwin Machinery (Omaha NE)
We now have a copy of the instructions and parts list for this Chicago Brake BB316 and BB216 - In the library, scroll down the page some and you'll see the description and linl to the pdf file.
http://www.thesheetmetalshop.com/module ... d-128.html |
_________________
"If you make your job important it is quite likely to return the favor" Author Unknown
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Post subject:RE: adjusting a Chicago brake
Posted: Aug 21, 2008 - 06:39 PM #7765
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Joined: Oct 22, 2007
Posts: 3
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I have looked through the library & do not find the link to "adjust a Chicago Box & Pan brake"
Please help me locate this link.
Tinkertoy1941 |
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Post subject:RE: adjusting a Chicago brake
Posted: Aug 22, 2008 - 02:29 AM #7770
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Webmaster
Joined: May 13, 2003
Posts: 1327
Location: Waukesha
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It's near the bottom of the page in the library in yellow back round.
Chicago - Dreis Krump Mfg Co.
Universal Box and Pan Bending Brake -
BB 316 - BB 216 Instructions and parts list (Click Here)
Special thanks to Chad from Gladwin Machinery & Supply Co. Omaha NE |
_________________
"If you make your job important it is quite likely to return the favor" Author Unknown
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