A Bender for Arch Bars

This forum is dedicated to the Live Steam Hobbyist Community.

Moderators: Harold_V, WJH, cbrew

User avatar
Pipescs
Posts: 1815
Joined: Wed Feb 03, 2010 10:16 pm
Location: Lester Alabama

A Bender for Arch Bars

Post by Pipescs » Mon Nov 20, 2017 9:38 pm

One of the distractions in my shop that pulls me from the Rust Bucket has been and ongoing project to produce a design for a 2.5 inch Arch Bar Truck. More on that later.

Another project has been the assembly of a set of Allen Arch Bar Trucks for the LE American to have a brake car to run behind the engine. More about that later.

Looking for a method to bend bars in my shop I was lucky enough to mention my dilemma to Gregg at Mid South Live Steamers.

He sent me a photo of his set up which I have kit bashed into this project. This took a weekend to draw, another weekend to make the pieces and total outlay of $26.00.
Charlie Pipes
USMC Retired

Current Projects:

2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
Little Engines American Restoration
Bobber Caboose

User avatar
Pipescs
Posts: 1815
Joined: Wed Feb 03, 2010 10:16 pm
Location: Lester Alabama

Re: A Bender for Arch Bars

Post by Pipescs » Mon Nov 20, 2017 9:51 pm

Gregg's original was meant to lock in a vise and bend thinner bars than I needed to work with.
526A16F0-4B09-4ED9-A30D-6A4615EAF39E (002).JPG
I don't own a large enough vise so I changed it to a plate system that I could bolt to a heavy bench with Lag Bolts.

I built the entire project in CAD and then when it looked right, started cutting parts.
Base Drawing.JPG
The main plate is six inches by nine. Mostly because that was the size of scrap I found at the steel yard to make it from.
DSC_5014.jpg
Charlie Pipes
USMC Retired

Current Projects:

2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
Little Engines American Restoration
Bobber Caboose

User avatar
Pipescs
Posts: 1815
Joined: Wed Feb 03, 2010 10:16 pm
Location: Lester Alabama

Re: A Bender for Arch Bars

Post by Pipescs » Mon Nov 20, 2017 9:55 pm

The bottom of the base was notched for a two inch plate to give me something to bolt to the bench underneath. I ended up using half inch lag bolts.
DSC_5018.jpg
Instead of bolting the two plates together I ended up doing short quick tack welds so the heat would not warp the top plate.
Charlie Pipes
USMC Retired

Current Projects:

2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
Little Engines American Restoration
Bobber Caboose

User avatar
Pipescs
Posts: 1815
Joined: Wed Feb 03, 2010 10:16 pm
Location: Lester Alabama

Re: A Bender for Arch Bars

Post by Pipescs » Mon Nov 20, 2017 9:58 pm

This was all done on the milling machine but a good band saw and a drill press would suffice. The material was Hot Rolled Steel
Base Rail.JPG
Charlie Pipes
USMC Retired

Current Projects:

2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
Little Engines American Restoration
Bobber Caboose

User avatar
Pipescs
Posts: 1815
Joined: Wed Feb 03, 2010 10:16 pm
Location: Lester Alabama

Re: A Bender for Arch Bars

Post by Pipescs » Mon Nov 20, 2017 10:01 pm

The block in line with the bending arm is the back block and the one the bend is forced around is the Die block. both are the same size.

The die block has different radius on the four corners to deal with different bends.
DSC_5023.jpg
Charlie Pipes
USMC Retired

Current Projects:

2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
Little Engines American Restoration
Bobber Caboose

User avatar
Pipescs
Posts: 1815
Joined: Wed Feb 03, 2010 10:16 pm
Location: Lester Alabama

Re: A Bender for Arch Bars

Post by Pipescs » Mon Nov 20, 2017 10:28 pm

The Bending Arm, Back Block and Die Block were all made from a length of one inch square cold rolled steel. Just because that was what I had laying in the corner.
Back Block.JPG
Die Block.JPG

The blocks had to be short to allow for the clearance when working all the bends
DSC_5021.jpg
Charlie Pipes
USMC Retired

Current Projects:

2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
Little Engines American Restoration
Bobber Caboose

User avatar
Pipescs
Posts: 1815
Joined: Wed Feb 03, 2010 10:16 pm
Location: Lester Alabama

Re: A Bender for Arch Bars

Post by Pipescs » Mon Nov 20, 2017 10:31 pm

The entire thing was bolted together with five 1/2-13 thread x inch and a half Allen Head Bolts and mounted to my bench with five two inch lag bolts.
Charlie Pipes
USMC Retired

Current Projects:

2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
Little Engines American Restoration
Bobber Caboose

User avatar
Pipescs
Posts: 1815
Joined: Wed Feb 03, 2010 10:16 pm
Location: Lester Alabama

Re: A Bender for Arch Bars

Post by Pipescs » Mon Nov 20, 2017 10:32 pm

I should mention the base plate is laid out in a way to accomidate .25 inch thick bars. If I do thinner bars for a smaller scale I will need to slide a shim between the stock and the Back Block
Charlie Pipes
USMC Retired

Current Projects:

2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
Little Engines American Restoration
Bobber Caboose

BClemens
Posts: 355
Joined: Sat Oct 08, 2016 10:04 pm

Re: A Bender for Arch Bars

Post by BClemens » Tue Nov 21, 2017 5:15 am

Charlie,

Super - but;
How do you know with certainty that all the bends are identical? What I mean is repeatable from one side frame to another?

Suggestion: the fixed block could maybe be moved to the center of the base block and sized as the center portion of the arch bar where the bolster risers fit. Then move your bend arm (or make a duplicate-better) and bend the two ends and inner riser portion at the same time - identical side frames. With a large enough base, you could incorporate the journal box ends too at the same time. Clamp the center and make both outer journal box bends at the same time too - maybe around removable dowel pins..which would also indicate correct center bend angles too.

Hope you don't mind the suggestion. I could see myself having trouble aligning bend lines to keep all of the side frames identical when the material is removed and repositioned for the opposite bend.

This is a great method especially your pivoting bend arms - that's ideal and very positive for bend angle.

OK - no more cracks from the peanut gallery!
BC
Last edited by BClemens on Tue Nov 21, 2017 5:33 am, edited 1 time in total.

User avatar
Pipescs
Posts: 1815
Joined: Wed Feb 03, 2010 10:16 pm
Location: Lester Alabama

Re: A Bender for Arch Bars

Post by Pipescs » Tue Nov 21, 2017 5:32 am

Funny you should mention that.

I am working on a stop block for the handle and have made two fixtures to act as go/no-go gages along with being drilling fixtures.
DSC_5037.jpg
the plan is to have a sliding block on the handle that I can set with each of the bends for a particular set of bars.

More later

Off to work.

Any input greatly appreciated as I don not need to reinvent the wheel so to speak.
Charlie Pipes
USMC Retired

Current Projects:

2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
Little Engines American Restoration
Bobber Caboose

BClemens
Posts: 355
Joined: Sat Oct 08, 2016 10:04 pm

Re: A Bender for Arch Bars

Post by BClemens » Tue Nov 21, 2017 5:38 am

I'm having a case of 'cabin fever'. - Had knee surgery yesterday so can't even stand at my vice!

BC

User avatar
Bruce_Mowbray
Posts: 642
Joined: Sat Jan 04, 2003 7:45 pm
Location: Pennsylvania

Re: A Bender for Arch Bars

Post by Bruce_Mowbray » Tue Nov 21, 2017 8:02 am

Great design Charlie!
An adjustable stop on the arm to repeat the amount of bend would be a good addition too. A stop similar to the one on a box and pan brake that allows over-bending to achieve the desired final angle. As with any bending job, fiddle with the first piece, make adjustments, then bend the rest. This will be a tool found in my shop in the near future. I have 8 sets of arch bar trucks to make.
Bruce Mowbray
Springville & Southern RR
TMB Manufacturing & Locomotive Works

Post Reply