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- Apr 28, 2008
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To go with my plasma table I am looking for a decent way to bend metal. I built a small sheet metal brake awhile ago and for thin guage stuff it works fine. I am looking for thicker materials and wider widths. Let me preference this by saying I know you will always want bigger. I started by seeing what was on the internet. I quickly realized the commercial ones were way to expensive and big for a mostly hobby machine in a 3 car garage. I started looking at home built. There is the SWAG press that goes into a HF press or build your own frame. It is a possibility I haven't completely given up on. I also found two others that caught my attention. First is BERSK on Pirate4x4 http://www.pirate4x4.com/forum/torchmate-cnc-forum/1024437-48-press-brake-project.html While it is cool and I have seen it in person it is still pretty expensive and big. The second is Jamscal laminated brake in a HF press. http://www.pirate4x4.com/forum/shop-tools/1004514-laminated-press-brake-idea-new.html It is cool cause of the flexibility his has but you are limited by the width of the Press just like a swag kit. You are also limited by the pressure of the ram.
I started looking around my garage and 99% of items I would want to bend were under 1/4" and under 3' wide. I started drawing up a press that is 3' wide and my plan is to power it with a 20 ton air over hydro ram cause they are cheaper then going full hydro. Looking at press charts 1/4" mild 3' wide with a 3" lower die is 27.3 tons. Using some mechanical advantage that could be possible to achieve with a 20 ton ram.
I am looking for opinions if it is strong enough or will I kill myself from an explosion if I build it. The plan is the main frame, bell cranks, shackles, ram mounts will be cut out of 1/2". The Dies would be cut out of 1/4" plate. The lower die will sit on a piece of 1"x2" on each side and the gussets under it would be cut out of 1/4" The bell crank arms are 8" from the pivot to the shackle and 12" from the pivot to the ram mount.
Overall view.
BRAKE 1 by Matthew Dresselhaus, on Flickr
With some dimensions.
BRAKE 2 by Matthew Dresselhaus, on Flickr
How the dies are placed. They will be laminated together. Based on the dimensions I saw on ebay some normal dies could be purchased and used as well.
BRAKE 3 by Matthew Dresselhaus, on Flickr
Before I go spend a $1000 on material and turn it into scrap I have a few questions.
1. Is the 1/2" frame strong enough or is there going to be to much deflection in it?
2. Am I right that due to the ratio change in the arms of 1:1.5 the 20 ton ram theoretically become 30 tons of pressure at the die?
3. I was thinking of using 1" grade 8 bolts at the pivot points with 1.5x.25 tube bushings sleeved thru the arms. Should I do something different here?
4. Are there any areas that I have grossly overbuilt or under built?
5. How much weaker would it be if I cut it all out of 1/4" plate? The parts I have drawn as 1/2" would be cut twice and stacked to make them 1/2" thick.
6. Anyone have any comments suggestions or changes I should make?
I started looking around my garage and 99% of items I would want to bend were under 1/4" and under 3' wide. I started drawing up a press that is 3' wide and my plan is to power it with a 20 ton air over hydro ram cause they are cheaper then going full hydro. Looking at press charts 1/4" mild 3' wide with a 3" lower die is 27.3 tons. Using some mechanical advantage that could be possible to achieve with a 20 ton ram.
I am looking for opinions if it is strong enough or will I kill myself from an explosion if I build it. The plan is the main frame, bell cranks, shackles, ram mounts will be cut out of 1/2". The Dies would be cut out of 1/4" plate. The lower die will sit on a piece of 1"x2" on each side and the gussets under it would be cut out of 1/4" The bell crank arms are 8" from the pivot to the shackle and 12" from the pivot to the ram mount.
Overall view.
BRAKE 1 by Matthew Dresselhaus, on Flickr
With some dimensions.
BRAKE 2 by Matthew Dresselhaus, on Flickr
How the dies are placed. They will be laminated together. Based on the dimensions I saw on ebay some normal dies could be purchased and used as well.
BRAKE 3 by Matthew Dresselhaus, on Flickr
Before I go spend a $1000 on material and turn it into scrap I have a few questions.
1. Is the 1/2" frame strong enough or is there going to be to much deflection in it?
2. Am I right that due to the ratio change in the arms of 1:1.5 the 20 ton ram theoretically become 30 tons of pressure at the die?
3. I was thinking of using 1" grade 8 bolts at the pivot points with 1.5x.25 tube bushings sleeved thru the arms. Should I do something different here?
4. Are there any areas that I have grossly overbuilt or under built?
5. How much weaker would it be if I cut it all out of 1/4" plate? The parts I have drawn as 1/2" would be cut twice and stacked to make them 1/2" thick.
6. Anyone have any comments suggestions or changes I should make?