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Jamscal's Mechanical Press Brake Thread for info and help

jamscal

Stainless
Joined
Sep 8, 2004
Location
Louisville, KY
I'm starting a new thread for Mechanical Press Brakes.

I hope to have some good info here and also ask for help and opinions when the need arises.

Pic of my Brake:

20160315_154954_zpsc5esi2pf.jpg


Unloading:

IMG_20160318_122647_zpsbxtiswda.jpg


It's a 90 ton Chicago Dreis & Krump with a 10' bed.

Crane operator says it weighs 20k lbs.

Hope to get it wired up this week.
 
Problem #1



Most of these brakes have a numerical readout to .001 for ram adjustment.

Mine has this :rolleyes5: ^^^

I want to get a DRO for the stroke adjustment. Good plan? What kind of DRO should I get?
 
Might want a non digital read out so you always have a reference

Yes, that would be the problem...


Does the 'absolute' referenced in some of the links provided by Kiwi mean it always knows where it is?

edit: where would i get a non-digital read out? (apart from mounting a dial indicator, which I thought of).
 
I would think they would be like the abs calipers, which seem to turn on right where they left off. Other option would be a 2 axis or even 3or 4 for your back gage too.
Easson
I have no experience with the readouts from them but I did use them for glass scales on my brake. They should work just like the newall on my manual mill that as long as there is power to the display (can be off just power to it) it knows where the scale is at all times. Worst case would be a power outage may force you to first run the nut all the way against stops to zero the display, but i think that would be rare. The displays do all sorts of other fancy features which you dont really care about but good cheap readout with abs/inc.
 
On to tooling. I have this 30 degree stuff about 6' long... 1 1/2 die opening:



I also have a 10' piece of this:



Radius looks like it's for 1/4" material.

I need currently to bend 3/16" mostly but I'd like to progress into generic tooling to bend 16 ga, 11 ga, 3/16 and 1/4".

Some say to start with 30 degree tooling anyway.
 
Would like advice on tooling.

I'd like to buy bottom dies in 4 opening sizes ( for 16 ga. 11 ga, 3/16 and 1/4" to start)

I have the upper punch for 1/4", pictured above.

I'd like to buy a smaller radius punch for the smaller stuff but don't want to buy 3 more...only one right now.

Question 1: Should I get 30 degree tooling for the above, or standard?

Question 2: Should I segment the punch(es) or is it better to leave long?

Question 3: Since I can only bend 6' of 1/4, should I only buy a 6' section of 2" opening v die?

Question 4: What radius on the new punch for 3/16 and thinner?

Work I do is general fab work and I've gotten by without a brake so far, so no special needs currently.

Thanks.
 
I agree, I would say that a 90 ton would be limited to 3/16".

6 foot of 1/4" over a 2" die opening requires 90 tons...same as 8' of 3/16" over a 1 1/2" die opening.

Not really wanting or needing to max the machine as much as decide what tooling to buy based on the max.
 
I have 90 ton Mercury mechanical and 8 foot of 10 gauge was really a load for it my 150 ton diacro would be fine but some of the sheets I get the heat treat and carbon makes a lot of difference in what you can bend I used to buy lots of seconds in sheets and it varies a lot on bending yield. But that's all I could afford to buy the big three can put a lot of pressure down on a little guy
 
Go it running and got the dro installed.

Seems repeatable enough after doing about 20 pcs. (still have a lot of learning I know)

Not as scary as I thought...actually pretty nice I can inch down just to the work easily.

(yes I do see the danger and how it deserves respect always)

May try to put some vids up when I'm more comfortable with it.

I think this might be a 90/125 ton machine as it's heavier than the 60/90 ton machines (20k vs 15k) and has a higher HP motor.

Also trying to determine year. Found one online, same model number that says 1975?

It has a Allis-Chambers 10 hp motor on there and I don't know when they started or stopped making motors.

Question:

What is the math to determine ram position to a given angle....(it's non-linear) ?
 


Got my employee doing a spreadsheet entering about 25 test bends and different ram positions to see if we can see a pattern and get a good starting point for further bends.
 
I had one of those DROs on my quill. I couldn't get it to repeat. Might not matter as much for that application though.
 
Ha, yes it didn't go far at all.

The DRO works and we use this brake all the time. Mainly on 7ga but a range from 11ga to 1/4".


The DRO mounts of course on either side of the ram adjustment, so there is a lot of slop in that as you go up and down.

Solution is adjust up and then come back down into the measurement each time (like you would for backlash on a lathe's cross slide).

Also, since the whole thing is basically a crankshaft on top of that, we only adjust the ram at the bottom of the stroke...to try to get repeatability.

Obviously this isn't a precision sheet metal shop, but the above method has got us the repeatability for out needs.
 
You have 1 DRO or one on each side of the ram?
Did you ever fit one to the back gauge?
These cheap DRO's are a low cost addition that can help a lot with repeatability,
I have one on the table of my small Hardinge Horiz. mill. Just curious how it helped
on the PB.
 








 
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