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adjustable collar jig

Joel OF

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Hey folks, thought I'd quickly share some pics of a collar jig I fabricated. I found some ABANA instructions on how to make an adjustable collar jig from a monkey wrench, my tool is inspired by that. I made this jig from stuff I had lying about the workshop. The mild steel chunks are 2 inch x 1 inch. The threaded rods are 12mm stainless (1/2 inch). There's a hardy shank welded on too, obviously. I've attached a pic of a test collar made from 40 x 6mm stock.


Measure out the collar material as you would anyway, then set the gate(?) opening to the width of your mandrel + 2 x the width of the collar material. Lay the collar material across the gap, put your mandrel on top of that and then strike down on the madrel to force the collar material into the gap.


I only made this today so I haven't had a chance to live with it and see how much I hate it in a week's time, but for the moment I'm really happy. One great benefit of it is that you can strike against the side of the jig so you're not chasing a skidding collar about your anvil face - I've tried to show this in the pic where you can see my hammer. (Blurry as it's hard to hold everything at once!)



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Hi Joel, That should be fine,  looks similar to the traditional engineers clamps, and a possible problem is the setting of the size for the collars, also to keep the jaws parallel when you are forging into them to form the U, it may also help if you put a large radius on the tools top inside edges to assist in forming the U


I would consider making spacer blocks for each size as a solid clamping rather than relying on the nuts as there is a possibility of bending the screw threaded bar over a period of time,


Don't want to hijack the thread but  this may be of value to anyone with a flypress,


Here are some pics for information of one I made and used on the flypress, (could also be used on the anvil too) as an alternative suggestion.


The jaws are adjustable, and stay parallel, it is also easy to adjust to various size mandrels, and to centre the blank using the the two scribed and whitened lines.


The collar being produced in the picture is for a bundle of three bars, 5mm, 12mm, 5mm, closed on the wide face of the bundle


post-816-0-64439600-1415152970_thumb.jpg  post-816-0-49920700-1415152989_thumb.jpg  post-816-0-05981900-1415153014_thumb.jpg  post-816-0-47425100-1415153226_thumb.jpg  


This is a picture of the radius on the jaw edge to assist starting when drawing the U into the limited space



Now let's see what you are fitting the collars to, it's good to see you coming on and developing your skills.

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I was concerned that the steel blocks would naturally want to toe inwards as they're only fastened at the back by the nuts, but they do stay parallel thankfully. It was a bit dark in the workshop by the time I took this pic so you can't really make out the radius I ground on each block as you described John. Cheers for the flypress jig pics, looks like a nifty little setup!


To help keep my collar seams centred I find the half way point of the collar material, then centre punch 3 times across the width of the material. I then start the sinking process by opening up the jaws of a vice, lay the collar material across the gap and hammer on the centre punched line with a ball pein.


Hopefully it'll soon be put to good use as I'm keeping my fingers crossed for a commission to make 2 smaller versions of some large driveway gates that have lots of scrolls and collars.

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