Repost of much earlier pix of bending trunion straps

[Cat Whisperer]

Here are the thumbnails:

[Cat Whisperer]

--- modified 2009-03-08 --- reposted from HUNT101.com the above thumbnails
working on the others.

Measurements were determined by guessing, making one, adjusting for the next.

Bending could be easily done by making a jig or fixture with a leaver arm.

Greasing the strap iron (1/8 x 1-1/4" IFRC) helped.

After making 2 or 3 (well maybe 6)  it was easy to get them smooth and uniform.

These are 2" all that's needed to do other sizes is a round fixture of the right size.

[Rickk]

What kind of machine is your "trunnion bender"?

[Cat Whisperer]

What kind of machine is your "trunnion bender"?

It is a Di-arco, model #1A.

Classic bender for wrought iron, commonly found in HS shops used for teaching.  The 1A is likely the smallest one they make.  You'll see these on a regular basis on ebay.  I paid $50 for mine, doesn't have some of the attachments, but I got my money's worth.

[lightning]

Thanks for the photos.  I am not a metal worker and recently built a naval carriage for my half scale 1841 six pounder.  The wood parts of the carriage, while not a piece of cake, I could make.  When it came to the trunnion caps I took some flat stock and after hours of heating and pounding, using a vice and a piece of pipe as as the guide, I got my trunnions hammered out.  With a little grinding they look fine.  I would have loved to buy them though and saved the time.  Does anyone manufacture these things like this?  It seems they would be fairly cheap for someone with the right equipment to make and sell to people like me who had trouble shelling out $100 or more for a set of cast iron trunnion caps.  THanks againg for the great forum.  I don't post often but I read it all the time.  I am working on the base for my Hern Iron Works mortar now and use this sight to gather all the info I need.

Lightning

[GGaskill]

I think the proper spelling of the bender's name is Diacro.  Pexto is another brand of bending machines.  Makes for more successful eBay searches.  (-:

[jeeper1]

Would this make trunion caps?
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=38471

[GGaskill]

I looked at that after finding its big brother on eBay.  If it meets its specs, it should be able to do the bends although the right angles may be a problem.  It needs to be checked out in person.

[Cat Whisperer]

I think the proper spelling of the bender's name is Diacro.  Pexto is another brand of bending machines.  Makes for more successful eBay searches.  (-:

Di-arco was right off the nameplate.  But doing a search on what is commonly used (and another search on common MISspellings) is profitable.

Pexto stands for Peck, Stow and Wilcox.  Both excellent brands.

[Double D]

This has got to be a good source of information on how to!

http://www.diacro.com/pdf/manuals/Art_of_Bending_Part1.pdf

http://www.diacro.com/pdf/manuals/Art_of_Bending_Part2.pdf

[Cat Whisperer]

Excellent!

These two present each of the basic bends with many different types/forms of material.

These in combination make up everything else.

One advantage of a hand-bender (any of several forms available) is that they use exactly the same clamping and bending techniques as the hydaulic and automated benders.  So it is worthwhile to use one to determine the nature of how the material behaves in specific clamping and bending situations.

We need to link to this, or a general topic/index of trunion bending, the sequences others have published here on other techniques of bending trunions - there are some good ones!

[Double D]

You know you guys are going to create a bidding war on Ebay...against each other!!

We'll leave this topic sticky'd to the top for a while until it cools off.  Then we'll link it and the orginal topic when the search engine comes back up and put that link in the Cannnon plans Sticky in the cannon hardware section.
 

[BoomLover]

Just a question, can the pics at the beginning of this threadbe re-posted? All it says is "file not found", and I'm looking for info on how to bend trunnion straps. Or is there another location I can find the info? Thanks, BoomLover

[Cat Whisperer]

I've been chasing through my old computers for the pix.  Have a 10gb that didn't have them, trying to get the 160gb drive up now.


-- just found the originals on HUNT101.com -- posted thumbnails above, working on the others.

[Cat Whisperer]

Initial setup - pin holds strap iron while nose piece bends the metal at a zero radius to almost 90 degrees.

[Cat Whisperer]

From above, two sharp - almost 90 degree bends.  Dimensions are discovered by trial and error.  When found, recorded for next set of same size trunions.

[Cat Whisperer]

Start of bending the radius.  Diameter of center piece is the same size as the trunion itself.

[Cat Whisperer]

Working the strap around the form piece - note the change in location of the pin.

[Cat Whisperer]

Note the 'sharpie' marks where the process started.
Note where the bottom strap lines up - you can adjust this for above or below the center as you choose.

[Cat Whisperer]

The two straps compared - almost the same.

[Cat Whisperer]

one trunion strap from a different perspective.

[Cat Whisperer]

Another shot -  perspective comparison.

[Cat Whisperer]

Laid out to mark locations for drilling the holes.

[Cat Whisperer]

Note that this is but just one method of bending trunions.

There are other threads of using mating forms and hydraulic or vice pressure that do the job well and fast.

You don't need a bender like I have.  Just drill a few holes for the pins and form pieces and bend as you can - if it's a hammer you will have some very authentic looking trunion straps.

[BoomLover]

Thanks, Tim, that all looks good now! Great help! I'll put it to good use! BoomLover

[GGaskill]

The Di-Acro bending manual mentioned in #9 above has moved to The Art of Bending.

[gulfcoastblackpowder]

Nifty.  I don't have access to a bending machine, but I do have access to an acetylene torch and a hammer.  Needless to say, they turn out a little more rustic looking than yours.

[Cat Whisperer]

Thanks, George, for chasing the URL.

You don't NEED a bending machine nor a tourch (unless it's really thick).

You need only a vise, hammer and madrel.  Do the sharp bends first, then it's just wrap it around the madrel and bring to the right form.  (Doing a sharp bend later in the game - even with a bending machine - is not pretty.)

Take pix!

[Boom J]

I remembered this thread that shows another way to form cap-squares, but couldn't find it in the stickies (I might have passed right over it), so I made a search, and finally lucked out and found it.

http://www.go2gbo.com/forums/index.php/topic,123779.0.html

[Double D]

I remembered this thread that shows another way to form capsquares, but couldn't find it in the stickies (I might have passed right over it), so I made a search, and finally lucked out and found it.

http://www.go2gbo.com/forums/index.php/topic,123779.0.html

RE: not found in stickies.

...it wasn't there.
...it should have been.
...it is there now.