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Model Forum / General / Models / September 2008



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mark@ems-fife.co.uk - 28 Sep 2008 14:51 GMT
Decided not to work today,first Sunday in years,and I`m bored rigid.
All the usual groups are dead,the yanks aren`t up yet,never again.
Someone must have some subject they want to post about even if it  is
only about saving some fifty year old lump of crap machine from the
skip.As long as it`s not Colchesters and Bridgeports.
Mark.
Mark Rand - 28 Sep 2008 15:04 GMT
>Decided not to work today,first Sunday in years,and I`m bored rigid.
>All the usual groups are dead,the yanks aren`t up yet,never again.
>Someone must have some subject they want to post about even if it  is
>only about saving some fifty year old lump of crap machine from the
>skip.As long as it`s not Colchesters and Bridgeports.
>Mark.

Sorry, no metal working. Took a load of rubbish to the tip. Did some
gardening. Just seen the finish of the GP. Now going back out to the shed to
clean up the mess I've made doing wood-spoiling for a couple of 9' long
bookshelves.

Mark Rand
RTFM
Tim L - 28 Sep 2008 15:15 GMT
>Decided not to work today,first Sunday in years,and I`m bored rigid.
>All the usual groups are dead,the yanks aren`t up yet,never again.
>Someone must have some subject they want to post about even if it  is
>only about saving some fifty year old lump of crap machine from the
>skip.As long as it`s not Colchesters and Bridgeports.
>Mark.

OKay, a hypoid oils question.

I've been working on a 50 yr old large marine gearbox, reassembling it
now with various new bearings etc.
The oil spec is vague, basically non-critical,  SAE 20 or 30 'engine
oil or good gear oil'. There's been an issue with the reduction gears
grating heavily in ahead gear, this seems to have been down to a
combination of worn bearings and the output gear loose on its taper.
All that has been sorted, but the output (spur) gear has wear marks,
the best word I can think of for them is 'striations', it's a pretty
fair bet that these will mean the gears are still noisy.
I happen to have a drum of EP90 hypoid oil which I would like to use,
thinking it might give the oil film a better chance of survival
between the gear teeth than if ordinary engine oil is used.
Two issues-
will it be of any benefit as regards the gears?

Second, the ball and roller bearings mostly have brass cages, is there
an issue with EP oils there? I know it can cause problems with some
plain bronze bearings but there are none in this box. Also is it
likely to cause any problems with the friction clutches (Ferodo-type
materials)?

In round figures the box is transmitting about 300 bhp, input at 600
rpm, 3:1 reduction. Sorry, not model-sized.

Thanks

Tim
John S - 28 Sep 2008 15:24 GMT
Well I've often wondered it's it worth fitting an R8 spindle to a
Triumph or Student and increase the stiffness by a factor of 7?

John S.
mark@ems-fife.co.uk - 28 Sep 2008 15:59 GMT
> Well I've often wondered it's it worth fitting an R8 spindle to a
> Triumph or Student and increase the stiffness by a factor of 7?
>
> John S.

Sounds like a cracking great idea John,especially if you weld it in.I
find an easier way is to put them in the skip first and all the other
junk on top,this helps to stiffen them up a bit.And....if you`re lucky
the scrap merchant doesn`t notice the bottom of the skip is light
scrap so you get top bucks for the whole load.
I knew there had to be a reason for R8 spindles existing in the first
place but I just couldn`t think what it was.
Mark.
John S - 28 Sep 2008 16:17 GMT
The reason the R8 spindle was invented was for a lecture by the
Machine tool Builder association in Paris [ Texas ] in 1938
They wanted to compare the best qualities of a NMTB 40 with a
hypothetical bad design.

Throwing together  a non standard diameter, a taper that matched
nothing, a drawbar for a non standard thread and dimensions only
suited to hold farm gate on hinges they came up with their
hypothetical bad design.

Bridgeport's saw it, not realising what it had been invented for, fell
in love with it and the rest is history <g>
mark@ems-fife.co.uk - 28 Sep 2008 16:41 GMT
> The reason the R8 spindle was invented was for a lecture by the
> Machine tool Builder association in Paris [ Texas ] in 1938
[quoted text clipped - 8 lines]
> Bridgeport's saw it, not realising what it had been invented for, fell
> in love with it and the rest is history <g>

Understood.I had thought it was the other way around.Bridgeport had
built this machine and when they came to put the taper in the spindle
discovered there wasn`t enough metal there for a proper machine tool
taper so looked around to see what they had.In the bar rack they found
a bit of bar with a taper on it (it wasn`t meant to be tapered but
that`s American steelmakers for you) and this bar fitted their
spindle.GR8 they said we have a tool holder that nobody will/can
copy,so that`s how the GR8 taper was born.Over the years it got
shortened to just R8.
Charles P - 28 Sep 2008 16:55 GMT
>> The reason the R8 spindle was invented was for a lecture by the
>> Machine tool Builder association in Paris [ Texas ] in 1938
[quoted text clipped - 18 lines]
>copy,so that`s how the GR8 taper was born.Over the years it got
>shortened to just R8.

Never understood why they persisted with R8 when they proved that QC30
(and therefore proper 30INT) would fit. I suppose they reckoned that
they'd "made a standard" which to some extent is true. But I'm with
you that it's a crap one.

Charles
Peter A Forbes - 28 Sep 2008 17:08 GMT
>Never understood why they persisted with R8 when they proved that QC30
>(and therefore proper 30INT) would fit. I suppose they reckoned that
>they'd "made a standard" which to some extent is true. But I'm with
>you that it's a crap one.
>
>Charles

Just to add to the story,
--
Peter & Rita Forbes
Email: diesel@easynet.co.uk
http://www.oldengine.org/members/diesel
http://www.stationary-engine.co.uk
http://www.oldengine.co.uk
Peter A Forbes - 28 Sep 2008 17:09 GMT
>Never understood why they persisted with R8 when they proved that QC30
>(and therefore proper 30INT) would fit. I suppose they reckoned that
>they'd "made a standard" which to some extent is true. But I'm with
>you that it's a crap one.
>
>Charles

Try that again.....

Why did we end up with so many variations on a theme with the INT30, 40 and 50?

Apart from the basic one, there are QC versions, and yet another set with
different holding threads.

Peter
--
Peter & Rita Forbes
Email: diesel@easynet.co.uk
http://www.oldengine.org/members/diesel
http://www.stationary-engine.co.uk
http://www.oldengine.co.uk
Mike cole - 28 Sep 2008 16:17 GMT
>> OKay, a hypoid oils question.
>
[quoted text clipped - 25 lines]
>
> Tim

What I was told when i used to rebuild british /jap bikes with wet
clutches was that EP oils would weck the plates.

Mike Cole
Cliff Coggin - 28 Sep 2008 19:15 GMT
> Second, the ball and roller bearings mostly have brass cages, is there
> an issue with EP oils there? I know it can cause problems with some
[quoted text clipped - 3 lines]
>
> Tim

From memory, the sulphur in EP oils will react with all brasses and bronzes.

Cliff Coggin.
Christopher Tidy - 30 Sep 2008 11:11 GMT
>>Second, the ball and roller bearings mostly have brass cages, is there
>>an issue with EP oils there? I know it can cause problems with some
[quoted text clipped - 5 lines]
>
> From memory, the sulphur in EP oils will react with all brasses and bronzes.

I thought the idea of extreme pressure additives was that they reacted
to a small degree with the exposed metal to form a protective coating?

Best wishes,

Chris
Chris Eilbeck - 28 Sep 2008 16:41 GMT
> Decided not to work today,first Sunday in years,and I`m bored rigid.
> All the usual groups are dead,the yanks aren`t up yet,never again.
> Someone must have some subject they want to post about even if it  is
> only about saving some fifty year old lump of crap machine from the
> skip.As long as it`s not Colchesters and Bridgeports.

Alright then.  We've got a fused-deposition modeller at work that we
use to make boxes, brackets etc. for various electroniccy things we
build.  You just design in SolidEdge and send the stl file to the
printer.  Many hours later, you've got whatever you designed.

What is the design flow if I were to use something like a KX3 cnc mill
to do a similar job?  How do I convert the design into G-codes?  I'm
used to doing something similar with a T-Tech PCB milling machine but
I can't see what I'd need to buy to move to using a small mill.

Chris
Signature

Chris Eilbeck

John S - 28 Sep 2008 17:02 GMT
> Alright then.  We've got a fused-deposition modeller at work that we
> use to make boxes, brackets etc. for various electroniccy things we
[quoted text clipped - 9 lines]
> --
> Chris Eilbeck

If you are using stl files that means 3D and a CAM program that will
convert stl to 3D moves in G Code.
Problem 1 is cost, the ones that can do this in fine detail with speed
and control are very expensive.
The cheaper ones that do this tend to be more 'arty' and have less
control over the toolpath but are very quick and easy to program.

Take a look at this website to get an overlook of what is needed.
http://www.vectric.com/WebSite/Vectric/cut3d/c3d_index.htm

They do have a working demo you can play with on the site where you
can play what if with a couple of sample jobs.

I have done a couple of small patterns on a converted X3 CNC for some
vintage car parts using this and they came out well.

John s.
Chris Eilbeck - 28 Sep 2008 17:13 GMT
>> Alright then.  We've got a fused-deposition modeller at work that we
>> use to make boxes, brackets etc. for various electroniccy things we
[quoted text clipped - 10 lines]
> Problem 1 is cost, the ones that can do this in fine detail with speed
> and control are very expensive.

How much?  For example, a second FDM is gonna cost me 20K and I'm
pretty sure things'd be faster and better surface finish with a small
milling machine in a lot of cases.

We've had stuff made outside but it seems very cheeky to ask a company
what design flow they've used so we can buy the same and never give
them any work in the future.

> The cheaper ones that do this tend to be more 'arty' and have less
> control over the toolpath but are very quick and easy to program.
>
> Take a look at this website to get an overlook of what is needed.
> http://www.vectric.com/WebSite/Vectric/cut3d/c3d_index.htm

Thanks.

> They do have a working demo you can play with on the site where you
> can play what if with a couple of sample jobs.
>
> I have done a couple of small patterns on a converted X3 CNC for
> some vintage car parts using this and they came out well.

Sounds good to me.

Chris
Signature

Chris Eilbeck

John S - 28 Sep 2008 17:36 GMT
> How much?  For example, a second FDM is gonna cost me 20K and I'm
> pretty sure things'd be faster and better surface finish with a small
[quoted text clipped - 7 lines]
> --
> Chris Eilbeck

One CNC is about £2500, FeatureCAM is about £5K as a rough guide.

JOhn S.
Chris Eilbeck - 28 Sep 2008 18:08 GMT
> One CNC is about £2500, FeatureCAM is about £5K as a rough guide.

Thanks, John.  Now I can start looking at putting a shopping list
together.

Chris
Signature

Chris Eilbeck

David Powell - 28 Sep 2008 18:35 GMT
In article
<acbbb4f1-c79d-4cf3-8169-25e8ed4f11c2@a70g2000hsh.googlegroups.com>,  
"mark@ems-fife.co.uk" <mark@ems-fife.co.uk>  in
uk.rec.models.engineering wrote:

>Decided not to work today,first Sunday in years,and I`m bored rigid.
>All the usual groups are dead,the yanks aren`t up yet,never again.
>Someone must have some subject they want to post about even if it  is
>only about saving some fifty year old lump of crap machine from the
>skip.As long as it`s not Colchesters and Bridgeports.
>Mark.

I closed early and took most of the day off to visit an amateur radio
junk sale - my junk box needs refilling.   Guy there had a wonderful
vehicle, one of those toy sized pickup trucks, the sort you want to
pick up and push along the road to wind up the flywheel, powered by a
RR Viper jet on the back.  It just fits.   So just manoeuvre that
traffic warden to the hot end...  Or would the suck end be better?

Regards,

David P.
Dragon - 28 Sep 2008 22:07 GMT
> I closed early and took most of the day off to visit an amateur radio
> junk sale - my junk box needs refilling.   Guy there had a wonderful
> vehicle, one of those toy sized pickup trucks, the sort you want to
> pick up and push along the road to wind up the flywheel, powered by a
> RR Viper jet on the back.  It just fits.   So just manoeuvre that
> traffic warden to the hot end...  Or would the suck end be better?

Use the hot end.
It has greater range.
You have to get quite close before being sucked in.

Henry
 
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