SMALL RADIUS BENDS IN COPPER TUBE

[Michael GilliganParticipant @michaelgilligan61133]

Charles,

Your subject continues to fascinate me; and I have just found an interesting image, here: **LINK** … Click the small image to view a large version.

http://www.vintagenorton.com/2010/05/350cc-model-40-nortons.html

… did they offer an option of bent or straight breather pipes ?

MichaelG.

.

P.S. Do you happen know to whom they sold the Aero/Auto part of the business, in 1935

Edit: I am pretty sure it must have been 'Benton & Stone' / Enots

… because the Trade Mark illustrated is the 'Surprised Man'.

Decent image here:

http://www.vintagenorton.com/2013/10/1938-benton-and-stone-enots-catalogue.html

Edited By Michael Gilligan on 04/12/2017 08:40:30

[duncan webster 1Participant @duncanwebster1]

6mm end feed elbows are listed at

**LINK**

you could ring the manufacturer and ask where to buy, or even scrounge some

[Brian Sweeting 2Participant @briansweeting2]

Posted by duncan webster on 04/12/2017 14:36:57:

6mm end feed elbows are listed at

**LINK**

you could ring the manufacturer and ask where to buy, or even scrounge some

Plumbers merchants should have those

Edited By Brian Sweeting on 04/12/2017 15:29:38

[CHARLES lipscombeParticipant @charleslipscombe16059]

Michael,

Prior to your photos I would have bet that these caps had only been made with the bent vent tube as only the bent version is shown in the B&L catalogue and I have never seen the straight version. It is highly likely that Nortons modified the caps to suit their own ideas as virtually every component on their works bikes was different to what the customer bought as a Norton racer.

The straight pattern would be better in practice as the vent tube tends to get in the way when re-fuelling. However if you are, like me, making reproduction stuff, it needs to be visually as close as possible to the original (for original sometimes read as what the customer believes is original).

In this context I looked up the bends described by Duncan but the increased diameter ends would prohibit their use unfortunately.

Best & Lloyd sold the auto/aero parts of their business to Benton and Stone (Enots) in 1933. One reason was probably that a major part of B&L's auto business had revolved around their oil pump which was a popular fitting to motorcycles in the 1920's. By 1933 most manufacturers were fitting internal oil pumps of their own design and the market for proprietary, external oil pumps had all but disappeared.

Chas

[Michael GilliganParticipant @michaelgilligan61133]

Posted by CHARLES lipscombe on 04/12/2017 20:50:14:

… The straight pattern would be better in practice as the vent tube tends to get in the way when re-fuelling. However if you are, like me, making reproduction stuff, it needs to be visually as close as possible to the original (for original sometimes read as what the customer believes is original).

.

Understood

MichaelG.

[CHARLES lipscombeParticipant @charleslipscombe16059]

To Mechman48:

I think your pipe bender could well solve my problem, and even if it does not, it is still an elegantly simple bit of gear that I would like to make for use in the future.

Can you please post a picture of the other side of the bender? Also the purpose and fixing of the collets? Sorry if these points seem obvious but I am very much a beginner.

Best wishes, Chas

[mechman48Participant @mechman48]

Posted by CHARLES lipscombe on 05/12/2017 20:54:37:

To Mechman48:

I think your pipe bender could well solve my problem, and even if it does not, it is still an elegantly simple bit of gear that I would like to make for use in the future.

Can you please post a picture of the other side of the bender? Also the purpose and fixing of the collets? Sorry if these points seem obvious but I am very much a beginner.

Best wishes, Chas

Hi Chas
​ I have the drawing for this in my files … when I find them after a clean up of paperwork, will pm you with copy once sorted. The collets / rollers allow for tighter bends.

George.

Edited By mechman48 on 05/12/2017 22:50:38

[Chris TriceParticipant @christrice43267]

Posted by Neil Wyatt on 03/12/2017 09:59:15:

I understand that the minimum bend radius for ductile tubes is equal to the diameter, so yes it is possible

Instinctively, I would think that's not the whole story. I imagine that wall thickness plays a big part. A thin wall tube is less bend friendly than a thick wall tube. No idea what the maths is that's involved.

[mechman48Participant @mechman48]

Posted by mechman48 on 05/12/2017 22:48:46:

Posted by CHARLES lipscombe on 05/12/2017 20:54:37:

To Mechman48:

I think your pipe bender could well solve my problem, and even if it does not, it is still an elegantly simple bit of gear that I would like to make for use in the future.

Can you please post a picture of the other side of the bender? Also the purpose and fixing of the collets? Sorry if these points seem obvious but I am very much a beginner.

Best wishes, Chas

Hi Chas
​ I have the drawing for this in my files … when I find them after a clean up of paperwork, will pm you with copy once sorted. The collets / rollers allow for tighter bends.

George.

Edited By mechman48 on 05/12/2017 22:50:38

​Chas, check your inbox, have sent you pm today.

Geo.

[CHARLES lipscombeParticipant @charleslipscombe16059]

Hi, Sometime back I enquired about bending small copper tube to a tight radius. Many people helped and Mechman48 replied privately with a drawing of his design. I have now made his device and the first photo shows some experimental bends made in 1/4-inch copper tube (4 mm bore dia). These will be perfectly suited to my needs with a little more experimentation. I have applied two small mods of my own. I made the base thicker with a reduced width portion so I could clamp the tool in my vice. I thought the device was working close to its limits with 1/4-inch pipe so I made the clamping block a bit more robust.

A very impressive response from all the forum members who assisted and much appreciated by me.

Thanks George!

Chas Lipscombe

[Danny M2ZParticipant @dannym2z]

Well done.

Reminds me of this quote: "Never interrupt someone doing what you said couldn't be done." – Amelia Earhart

* Danny M *

[Tim StevensParticipant @timstevens64731]

I wonder whether Mechman48 could be persuaded to offer his drawings more generally? It is almost possible to work it out from the photo, though. I presume that the far block is bored to the pipe size – or has a loose collet to accommodate different sizes?

I do wonder about a version with a straight former (hollowed out to the relevant radius) in place of the small roller. The former would be a loose part, arranged to rest against the fixed roller, rolling round it as the handle was pulled, and would be intended to avoid the minor reverse radius kink at the end of the bend.

I am always nervous using my off-the-shelf version made as it is from a rough light-alloy casting. This looks a much more reliable job, and not too complex to make or adjust. Excellent

Cheers, Tim

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