Subject: Re: [Shop-talk] tubing bender dies

From: John Innis <[email-masked]>
Date: Wed, 18 May 2016 08:32:21 -0500

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Not sure about materials, but you don't need to shape your cutting tool, IF
you are patient and careful.  You can use a thin cutting tool and remove a
very small amount of material from the center of where you want your
groove.  Then widen the groove until it is the diameter of the tubing
stock.  Then remove a small amount of material from the center of the
groove and then widen the groove until is the width of your stock MINUS the
change in radius for the depth of the groove.  You can find the change in
radius buy subtracting the dept of the groove from the width of the stock
and multiplying by 2.  Keep doing this and you get a successive
approximation of a half circle groove.  The less material you remove in
each pass, the more accurate your radius will be.  You can then clean up
with a sanding tool if needed to remove any residual ridges.

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On Wed, May 18, 2016 at 7:00 AM, Brad Kahler <[email-masked]> wrote:

> I was given one of these tubing benders from Harbor Freight.  By
> design it bends flat stock rather well.
>
> http://www.harborfreight.com/compact-bender-38470.html
>
> I now have a need to bend some 5/8" diameter OD 1/16" wall tubing.
> I've been shopping around for dies but the prices I'm finding are
> fairly high for a one time need to make a couple of bends.
>
> I've got a nice 13" South Bend lathe so I'm thinking I should be able
> to fabricate the dies myself.  Would a material like Delrin would be
> suitable for the dies?
>
> Assuming I do decide to try and turn the dies myself I would also need
> to figure out how to grind the cutting tool to shape the curve.
>
> I'm looking for suggestions on how to accomplish this task.
>
> Thanks!
>
> Brad
> _______________________________________________
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-- 
=================================
= Never offend people with style when you   =
= can offend with substance --- Sam Brown  =
=================================

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<div dir=3D"ltr">Not sure about materials, but you don&#39;t need to shape =
your cutting tool, IF you are patient and careful.=C2=A0 You can use a thin=
 cutting tool and remove a very small amount of material from the center of=
 where you want your groove.=C2=A0 Then widen the groove until it is the di=
ameter of the tubing stock.=C2=A0 Then remove a small amount of material fr=
om the center of the groove and then widen the groove until is the width of=
 your stock MINUS the change in radius for the depth of the groove.=C2=A0 Y=
ou can find the change in radius buy subtracting the dept of the groove fro=
m the width of the stock and multiplying by 2.=C2=A0 Keep doing this and yo=
u get a successive approximation of a half circle groove.=C2=A0 The less ma=
terial you remove in each pass, the more accurate your radius will be.=C2=
=A0 You can then clean up with a sanding tool if needed to remove any resid=
ual ridges.<br><br><br><span style=3D"font-family:monospace,monospace">____=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0 ____<br>=C2=A0=C2=A0=C2=A0 |_=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 _|<br>=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 |=
_=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 _|<br>=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0 |_ =C2=A0=C2=A0 _|<br>=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0 |__|</span><br></div><div class=3D"gmail_extra"><br><=
div class=3D"gmail_quote">On Wed, May 18, 2016 at 7:00 AM, Brad Kahler <spa=
n dir=3D"ltr">&lt;<a href=3D"mailto:[email-masked]" target=3D"_blank">b=
[email-masked]</a>&gt;</span> wrote:<br><blockquote class=3D"gmail_quote=
" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">I=
 was given one of these tubing benders from Harbor Freight.=C2=A0 By<br>
design it bends flat stock rather well.<br>
<br>
<a href=3D"http://www.harborfreight.com/compact-bender-38470.html" rel=3D"n=
oreferrer" target=3D"_blank">http://www.harborfreight.com/compact-bender-38=
470.html</a><br>
<br>
I now have a need to bend some 5/8&quot; diameter OD 1/16&quot; wall tubing=
.<br>
I&#39;ve been shopping around for dies but the prices I&#39;m finding are<b=
r>
fairly high for a one time need to make a couple of bends.<br>
<br>
I&#39;ve got a nice 13&quot; South Bend lathe so I&#39;m thinking I should =
be able<br>
to fabricate the dies myself.=C2=A0 Would a material like Delrin would be<b=
r>
suitable for the dies?<br>
<br>
Assuming I do decide to try and turn the dies myself I would also need<br>
to figure out how to grind the cutting tool to shape the curve.<br>
<br>
I&#39;m looking for suggestions on how to accomplish this task.<br>
<br>
Thanks!<br>
<br>
Brad<br>
_______________________________________________<br>
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et=3D"_blank">http://www.team.net/donate.html</a><br>
Archive: <a href=3D"http://www.team.net/archive" rel=3D"noreferrer" target=
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Forums: <a href=3D"http://www.team.net/forums" rel=3D"noreferrer" target=3D=
"_blank">http://www.team.net/forums</a><br>
alk/[email-masked]" rel=3D"noreferrer" target=3D"_blank">http://autox.te=
am.net/mailman/options/shop-talk/[email-masked]</a><br>
<br>
</blockquote></div><br><br clear=3D"all"><br>-- <br><div class=3D"gmail_sig=
nature">=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D<br>=3D Never offend people with style whe=
n you=C2=A0=C2=A0 =3D<br>=3D can offend with substance --- Sam Brown=C2=A0 =
=3D<br>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D</div>
</div>

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Archive: http://www.team.net/archive

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From: Brad Kahler <[email-masked]>
Date: Wed, 18 May 2016 10:53:37 -0400

John,

That's an interesting approach to cutting the appropriate groove for
the dies.  For this particular project I think just having several
points of contact around the circumference where the pipe contacts the
ridges would be sufficient to support the pipe.

There is nothing critical about the looks or shape of the pipe.  What
I'm trying to do is create a 90 degree bend in the 5/8" tubing which
is going to be used on the gas tank filler neck on my motorhome.  I'm
adding a vent line so the tank fills easier (i.e. faster).

Thanks for the tip!

Brad

On Wed, May 18, 2016 at 9:32 AM, John Innis <[email-masked]> wrote:
> very small amount of material from the center of where you want your groove.
> Then widen the groove until it is the diameter of the tubing stock.  Then
> remove a small amount of material from the center of the groove and then
> widen the groove until is the width of your stock MINUS the change in radius
> for the depth of the groove.  You can find the change in radius buy
> subtracting the dept of the groove from the width of the stock and
> multiplying by 2.  Keep doing this and you get a successive approximation of
> a half circle groove.  The less material you remove in each pass, the more
> accurate your radius will be.  You can then clean up with a sanding tool if
> needed to remove any residual ridges.
>
>
> ____                ____
>     |_            _|
>       |_        _|
>         |_    _|
>           |__|
>

[email-masked]

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From: Dave <[email-masked]>
Date: Wed, 18 May 2016 16:23:35 -0400

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Why not just buy some rope pulleys of the right diameter?

http://www.mcmaster.com/#rope-pulleys/=12guu0a

Dave Massey

-----Original Message-----
From: Brad Kahler <[email-masked]>
To: Shop Talk List <[email-masked]>
Sent: Wed, May 18, 2016 11:26 am
Subject: [Shop-talk] tubing bender dies

Thanks!

Brad

[email-masked]

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<font color='black' size='4' face='Arial, Helvetica, sans-serif'><font size="4">Why not just buy </font><font size="4">some rope pulleys of the right diameter?<br>
<br>
http://www.mcmaster.com/#rope-pulleys/=12guu0a<br>
</font>
<div> <br>

</div>

<div> <br>

</div>

<div style="clear:both"><font size="4">Dave Massey</font><br>

<br>

</div>

<div> <br>

</div>

<div> <br>

</div>

<div style="font-family:arial,helvetica;font-size:10pt;color:black">-----Original Message-----<br>

From: Brad Kahler &lt;[email-masked]&gt;<br>

To: Shop Talk List &lt;[email-masked]&gt;<br>

Sent: Wed, May 18, 2016 11:26 am<br>

Subject: [Shop-talk] tubing bender dies<br>

<br>

I was given one of these tubing benders from Harbor Freight.  By<br>

<br>

<a href="http://www.harborfreight.com/compact-bender-38470.html" target="_blank">http://www.harborfreight.com/compact-bender-38470.html</a><br>

<br>

I now have a need to bend some 5/8" diameter OD 1/16" wall tubing.<br>

I've been shopping around for dies but the prices I'm finding are<br>

<br>

I've got a nice 13" South Bend lathe so I'm thinking I should be able<br>

to fabricate the dies myself.  Would a material like Delrin would be<br>

<br>

<br>

I'm looking for suggestions on how to accomplish this task.<br>

<br>

Thanks!<br>

<br>

Brad<br>

<br>

Shop-<a href="mailto:[email-masked]">[email-masked]</a><br>

Archive: <a href="http://www.team.net/archive" target="_blank">http://www.team.net/archive</a><br>

Forums: <a href="http://www.team.net/forums" target="_blank">http://www.team.net/forums</a><br>

<br>

</div>

</font>
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[email-masked]

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From: David Hillman <[email-masked]>
Date: Wed, 18 May 2016 16:26:56 -0400 (EDT)

> adding a vent line so the tank fills easier (i.e. faster).

Brad,

    For those minimal requirements, it seems like you'd be time way ahead
making a simple bender from scratch, if you have some scrap metal handy.
Here's the one I made a few years ago...

<http://planet-torque.com/welding/bracket-bender-4.jpg>

    Two posts are fixed to the base, in this case a scrap of square tube,
and one is fixed to the arm, here a flat scrap.  One hole drilled in the
arm is the pivot point.

    Or you could just find something round with a useful radius -- like a
wheel -- and bend the tube over that by hand.  Doesn't take much to bend
5/8" x 1/16" material.

--
  David Hillman

[email-masked]

---

From: Brad Kahler <[email-masked]>
Date: Wed, 18 May 2016 16:30:49 -0400

Dave,

That's not a bad idea, unfortunately I just checked and all of the
pulleys designed for 5/8" rope are pretty darn expensive and I would
need at least two of them :(

For the moment John's idea of how to make the pulleys is probably the
easiest/cheapest approach.

[email-masked]

---

From: Dave Cavanaugh <[email-masked]>
Date: Wed, 18 May 2016 20:01:21 -0700

I think I would make the dies out of maple or oak on my wood lathe, but 
I'm primarily a wood guy.  You can turn wood on a metal lathe (but it's 
messy) and you could just grind a quickie tool with the appropriate 
radius out of a piece of scrap or old file since you're only turning wood.

On 5/18/2016 5:00 AM, Brad Kahler wrote:
> Unsubscribe/Manage: http://autox.team.net/mailman/options/shop-talk/[email-masked]
>
>

[email-masked]

---

From: David Scheidt <[email-masked]>
Date: Thu, 19 May 2016 11:59:30 -0500

> easiest/cheapest approach.

The cheapest and easiest approach is surely to have someone with a
suitable tubing bender bend it for you.  5/8 is used for some exhaust
stuff, a good custom muffler place might have a die.   Second simplest
is likely to use a piece of flexible tubing, either for the whole
piece, or just the bend.  Something like
http://www.bennettbuilt.com/shop/Muffler_Accessories--Stainless_Steel_Flexible_Exhaust_Tubing_58_ID.html
should probably work...
_______________________________________________

[email-masked]