DIY Backplate...

[edthesped]

Starting to work up a backplate. I found a design somewhere on this board, modeled it up in CAD and made a few changes...

On all the templates I found I noticed the slot width at the top of the plate for the shoulder straps is less than 2", is there a reason for that? I'm thinking all of the slots should be just over 2" wide, (2 1/16"), to accept a 2" harness; or am I missing something?

Also, is the hole separation for the wing universal or does it vary by manufacturer? I recall reading 11" somewhere.

Ideally the backplate will be a kind of universal setup that will take pads and wings from any manufacturer. Any dimensions that can be offered up will be greatly appreciated.

Attached is a 3D pdf file for the single tank version, click on the "click to activate..." tab in the upper left hand corner of the sheet to enable the 3D model.

Based on using 10 ga. SS My plate shows to weigh ~6.5#, I'd like to trim the weight down a bit if possible.

An arrangement drawing and flat layout DXF file will follow once I get this close to being final. A multi tank BP will follow.


View attachment bp2.pdf

 

[aquaregia]

Awesome, based on Huw Porter's design. He's on this board sometimes. I've seen scuba webbing sold as 1 7/8" before, not sure if that helps you any.

 

[knowone]

It's anomalous

Minimum slot size unless you are using a 1" crotch strap is two inch

Diagonal top slots are 2-1/4

Play around with top slot distances and angles
to direct the webbing closer to your neck and
sternum

Play around with wood or plastic where anything achieved would result
in a far better,easily more comfortable outcome than any current plate


COMFY

 

[edthesped]

Awesome, based on Huw Porter's design. He's on this board sometimes. I've seen scuba webbing sold as 1 7/8" before, not sure if that helps you any.

Yes it is based on his work. Thanks for posting his name so I could back into where I got the information from, as I should give credit where it is due...

Stainless Steel Single-tank SCUBA Backplate

I won't have time to mess with this more until next week but I'm thinking I'm going to round the plate more like Halcyon. I also need to add a crotch strap slot and bump the lower corners out. Can anyone explain the reasoning for bending the lower corners of the plate?

 

[huwporter]

On all the templates I found I noticed the slot width at the top of the plate for the shoulder straps is less than 2", is there a reason for that? I'm thinking all of the slots should be just over 2" wide, (2 1/16"), to accept a 2" harness; or am I missing something?

Two approaches here - wider/longer slots are easier to thread and allow some movement/flexibility of the harness; narrower/shorter slots hold the harness more securely with no risk of the webbing slipping, and webbing is a little malleable, so the slot can be the same width as, or even fractionaly narrower than, the webbing. Don't forget though that if the webbing is folding at an angle, the diagonal will be longer than the 'width' of the webbing.

Also, is the hole separation for the wing universal or does it vary by manufacturer? I recall reading 11" somewhere.

11" (280mm) is standard.

Can anyone explain the reasoning for bending the lower corners of the plate?

To reduce the tendency for the bottom corners to dig in to your hips, particularly when used with a single tank.

Nice work with the template!

HTH,
Huw

 

[lucca brassi]

DIY Backplate ... friend of my buddy made some Alu plate with lasercut CNC and CNC bending machine . Nice work but he left me sharp edges for holes and slots for harness webbing . (maybe I'll attach pictures later at home)

I'll try my best with these tools , but edge looks a little better as doing that with normal knife ...doesn't have real nice rounded radius as backplates from upper link.

Is any good advice how to do that? What is right english word for that tools ?



I have thought to take special machine for ''desharpening edges''(don't know correct word for that in english language ) with ''stones'' like




but I think in that case will be also flat surface a little bruised ? (now have aluminium glossy colour )

 

[ams511]

Lucca, to deburr the edges use a file and some emory paper. It will not look as pretty as the plates above but it will work. Alternatively you can run some old bike inner tubes through the slots so your webbing doesn't get cut. You do not need to place the plate into a tumbler.

 

[Seraphimx]

I`ve used the upper tool the knife to take out the edges. The problem is that the two new edges are smaller but still sharp.
If you use the knife you'll need to sand it afterwards.

 

[Bob3]

Don't forget that when using thin material (like 10 ga. SS) that the thickness of the material itself precludes a nice radius from being applied to the edge of a webbing slot, so you might want to consider using anti-chafing material (like bicycle innertube, plastic insert, etc) in way of the slots, or at least the ones taking most of the load.
That may require a slightly larger hole to accommodate the webbing + chafing gear.

 

[edthesped]

I was thinking a tumbler might help round the edges. 10 ga isn't too bad to round the outside edges but I've never had to worry about slots on any material we work with.

Aren't backplates typically 10 ga, (0.1345")? My model gives a weight of 6 1/2 # which is in line with stated weights for other ss backplates.

Also, the upper tool is called a deburring tool.

A dremel might be another option...

Doh!!! I just realized I have a Halcyon Al plate. Pulled out the calipers and it comes in at .130" around 10 ga thickness for steel but from my minimal understanding of Al, 8 ga. I assume that the SS plate will come in around the same thickness. Anyone with calipers and a steel plate able to verify?