Gabro folder HELP!

[HillclimberParticipant @hillclimber]

After hauling it out occasionally and using on the bench for some simple work, I finally finished the stand for my Gabro BF620-2 folder. I need to commission it properly before making a couple of aluminium 'lids' I need for a transmission tunnel and radiator cowl. Neither is a simple pan, but one is certainly more complex and will need a little-used feature for what the scant manual describes as 'Interrupted or Selective Bends'.

There are no images of this in the manual, but I found one photo from the web which shows the Gabro being used in a configuration like a 'normal' box and pan folder. However, there is descriptive verbage about this in the manual:

"Selective bends i.e. bends requiring only a part of the clamped material to be bent is made as follows:

1. Remove the Fold Bar Angle and the bolts which hold it.

2. Fit the Bed Raising Plate on to the Bed with the front edges level, after sufficiently retracting the Adjuster Screws.

3. Set up the work piece in the normal manner.

4. Select or cut a Bending Plate a little narrower than the width of the portion to be bent and stand it up in the channel accurately beneath the part to be bent (with the 90mm dimension vertical) and make the bend. The Bending Plate will operate either leaning outwards to give more leverage or flat against the fold bar. In the latter position it can be used to tighten the root of the bend. If the Plate slips it can be held by simply dropping the 3mm thick Packer into the channel in front of the Plate."

The problem is that my machine has no Bed Raising Plate or Bending Plates, neither of which is illustrated in the parts diagram. And the Bending Plate Channel Front and Bottom, which are items 55 and 56, have also been removed and lost by some former owner.

My challenge is to recreate these pieces, and I need the help of a kindly owner to measure them up for me?

Starting with the items 55 and 56, and ‘reading' the rust stains and paint overspray, my guess is that Plate Channel Bottom is simply a bright bar of 3/4”x1/4”? And the Plate Channel Front a similar 1 1/4”x1/4”?

That would leave a channel of 1/4” depth and 1/2" height to drop the bending plates into, described earlier as 90mm in length. And if those instructions in ‘4’ above say there is room for a 3mm spacer, the arithmetic suggests the bending plates are themselves 3mm thick – although that sounds a bit skinny to me as that width constitutes the contact face of the bending plate?

I am going to guess that the Bed Raising Plate is again just a piece of bright bar. This one the width of the bed and the thickness of the Fold Bar (to which the Plate Channel is fixed), hence 1 3/4”x1/2”? And that this Bed Raising Plate simply sits on top of the Bed, located by the two roll pins that can be pushed up and proud of the Bed.

Finally, there is presumably some logical sequence for the width of a series of Bending Plates, if I am going to make them in anticipation. It wont be Fobinacci, but something like 1”, 2”, 3”, 7” and 13”, which would combine to cover everything up to the capacity of this bender within the 1” recommended tolerance?

Any patient help appreciated. I did try MJ Allan for spares of these, but they dont keep them as parts – and the one chap I spoke to said he had never known anyone to use the feature!

Cheers, Colin

[HillclimberParticipant @hillclimber]

[BazParticipant @baz89810]

Just checked my Gabro and I have the following pieces, one of each 3mm x 50 mm x 560, 6mm x 90 x 600 and 1/2 x 1 1/2 x 24 with two roll pins fitted, these bits came with the machine, Please feel free to PM me if you need any more.

[HillclimberParticipant @hillclimber]

Baz, many thanks for that insight.

The last piece is undoubtedly the Bed Raising Plate, although I am wee bitty surprised it is just 1 1/2" wide. Is that the same as the width of the bed on your machine? And I'll check my own measurement.

Can I assume that the other two bars have a series of 8 off, 6mm clearance holes along their face?

Cheers, Colin

[Colin HeseltineParticipant @colinheseltine48622]

Hillclimber,

I have just checked my 620 folder.

The bending plate channel front is 24" long x 1.75" high x 0.25" thick.

The bending plate bottom spacer is measured as near as possible 22.25" long x 0.750" tall x 0.375" thick

On my machine this gives a slot as near as possible to 1" in depth.

The documentation lists the bending plates as being 90mm x 6mm in lengths of 600mm, 100mm, 50mm, 25mm, 12mm.

The bending plate packer just says it is 3mm thick.

I do not have a Bed Raising Plate or the bending Plates or Packers and will now get some made.

The bed on my machine is 1.75" wide so I would have expected the bed raiser plate to be the same width.

Colin

[Colin HeseltineParticipant @colinheseltine48622]

The top photo shows the bending channel front and in the second photo (on its side) you can just see the spacer bar.

Colin

[BazParticipant @baz89810]

Colin my machine is a BF620-2 so should be identical to yours, there are NO holes in my plates.

[HillclimberParticipant @hillclimber]

I think I have reached the bottom of this one.

Baz, let me correctly identify the three pieces of metal that you have. The 3x50x560mm piece is the Packer. This is dropped into the bending channel to block the Bending Plate. You have a single Bending Plate, which is the piece 6x90x600mm. The machine's full set was identified by Colin H as 12, 25, 50, 100 and 600mm (although I doubt I would use these sizes myself, if making them)..

The third piece you have is the Bed Raising Plate, although I struggled to identify its correct width. It seems to be 1/4" narrower than the bed itself. With the roll pins located centrally, the leading edge of the bed is displaced rearward by 1/8" – but I think this makes sense when realising that the Bending Plate extends forward from the folding bar.

The bending channel is formed from a Plate Channel Bottom of 3/8"x3/4"x22 1/4". Which provides the space to hold the combined Bending Plate and Packer, with a 1/2mm tolerance when fronted by the Plate Channel Front of 1/4"x1 3/4"x24". These have a series of eight holes through which 6mm screws pass to locate them to the fold bar.

Thank you both. Now the search for some of these bright bars commences….

Cheers, Colin

Edited By Hillclimber on 15/09/2021 18:08:17

[Colin HeseltineParticipant @colinheseltine48622]

I too will be searching for suitable bright bar to make the missing pieces.

Colin

[Colin HeseltineParticipant @colinheseltine48622]

Hillclimber,

I cannot reconcile your comment about the bed being displaced 1/8" rearwards. If you look at instruction 2 in your initial post it states:

2.Fit the Bed Raising Plate on to the Bed with the front edges level, after sufficiently retracting the Adjuster Screws.

I wonder if Baz could confirm whether the roll pins in his 1.5" x 1/2" x 24" bar are on the centre line, i.e. 3/4" in from each side of the bar. Perhaps this is not an original and was made by the previous owner.

Based on cost of piece of bar I think I would want to get the width right first time.

Have not as yet found any 90mm x 6mm, but can find 100mm x 6mm. It may be a case of milling off the unwanted 10mm.

These extra bits will certainly make the folder more versatile.

Regards,

Colin

[HillclimberParticipant @hillclimber]

Colin, good spot. As it bothers to specify installation detail of front edges, I do wonder if the roll pins are central? Over to you, Baz…

For 90×6 BDMS, I see it sawn to size here…

Cheers, Colin

[BazParticipant @baz89810]

The pins are offset, just tried the bar on the machine and it comes flush at the front. Hope this helps.

[Colin HeseltineParticipant @colinheseltine48622]

Baz,

Thanks for confirming that. Hillclimber and I can now source suitable BMS stock to manufacture our missing bits.

Colin

[Colin HeseltineParticipant @colinheseltine48622]

Material now on order.

Colin

[HillclimberParticipant @hillclimber]

Posted by Baz on 16/09/2021 10:21:28:

The pins are offset, just tried the bar on the machine and it comes flush at the front. Hope this helps.

Immeasurably. Baz, thanks.

Cheers, Colin

[not done it yetParticipant @notdoneityet]

That brake looks to be a very capable machine. A lot of money for a two foot bender – but, as always, you gets what you pays for (above the basic machinemart, etc, jobbies!).

I was hoping to make space for a Magnabend build this year, but it looks like it’s not going to happen – too much else going on. I thought the costs were going to be similar – except that metal costs have rocketed lately.🙁

[Colin HeseltineParticipant @colinheseltine48622]

It is a very versatile machine. I have not used half its capabilities. It does a great job of putting rolled ends on aluminium sheet. Just fit a piece of tube of the required radius over a length of the right angled hold down bar and fitted between the support arms. Pull the clamp lever lightly down and then raise the folder arm. Release the clamp arm slightly, slide the work material in a bit further and then repeat. Keep going till required radius achieved. I made hundreds of aluminium panels in this way for work.

Colin

[not done it yetParticipant @notdoneityet]

Oops, forgot to say I was hoping to make one with at least a metre capacity.

[HillclimberParticipant @hillclimber]

Posted by not done it yet on 16/09/2021 11:42:46:

That brake looks to be a very capable machine. A lot of money for a two foot bender

I doubt any sane person, and certainly not anyone on this forum, would buy a new one. But they appear regularly in bay of fleas for a few hundred pounds. And there is a 1m version.

My advice, if looking, is to wait for one with a stand (they weigh close to 100kgs) and a lot of loose bits. I am now paying the price in terms of reinstating this one. But they are a joy to use.

Cheers, Colin

[Colin HeseltineParticipant @colinheseltine48622]

All bending plates now made. Cocked up on packer plate as order 5mm not 3mm thick. 3mm should arrive in next day or so. Think I will remove the existing base bar with the dowel holes from the folder and clamp the raiser bar to it in order to correctly locate the two dowel holes. That might be tomorrows task. Just mowed almost 1/2 acre of grass in the pouring rain. Lawn looks better but I am a trifle damp.

Colin

[HillclimberParticipant @hillclimber]

I'm travelling this week, and cant show pictures. But I finished my construction before leaving, and painted the relevant bars, to assemble upon my return.

I cheated in respect of the bed raising plate, by buying a new spare from MJ Allan, which has them available. That fixed any alignment question in that respect. But I was pleased with the alignment of the additional replacements I needed for the the bending plate. Used an aerosol of Paragon's 'Startrite Green' hammer finish, and found it was a delight to use and produced an unusually good hammer finish. But, of course it's the wrong green (and no it does not matter, and it will stay that way).

Cheers, Colin

[HillclimberParticipant @hillclimber]

I assembled my replacement components yesterday and can now use my Gabro folder to manage interrupted folds that include angular pans and some particular tabs – it can now be operated much as other pan folders, as well as 'Gabro-Style'.

It's easy to see the general layout from the wonderfully-clashing shades of green. From the top: the bed-raising, which sits in the conventional bed and located by rollpins; a bending plate, sized to the fold and made in a number of lengths; the Packer, my own including offset holes drilled to provide finger pulls; and the Bending Plate Channel, while the Spacer is located behind and cant be seen.

There is also a picture of a knockout tab being bent on a piece of scrap, to illustrate something of what is now simplified. Looking at other pictures on the web, I dont think the older 'plain' green machines were equipped with this facility?

Cheers, Colin

Edited By Hillclimber on 11/10/2021 11:56:43

[Colin HeseltineParticipant @colinheseltine48622]

That looks good. Material has arrived for the packer, and the pins you sent arrived last week (thank you). Think will remove the existing top bar and clamp the two together to ensue holes in right place.

That folding looks great.

Colin

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