On Monday, 24 November 2014 21:51:08 UTC+5:30, Ed Huntress wrote:
On Mon, 24 Nov 2014 07:31:14 -0800 (PST), Sandarpan Mukherjee
wrote:

On Sunday, 23 November 2014 22:44:13 UTC+5:30, Ed Huntress wrote:
On Sun, 23 Nov 2014 08:48:09 -0800 (PST), Sandarpan Mukherjee
wrote:

On Sunday, 23 November 2014 12:32:13 UTC+5:30, Ed Huntress wrote:
On Sat, 22 Nov 2014 21:14:38 -0800 (PST), Sandarpan Mukherjee
wrote:

On Sunday, 23 November 2014 06:33:42 UTC+5:30, Ed Huntress wrote:
On Sat, 22 Nov 2014 18:25:32 -0600, Martin Eastburn
wrote:

On 11/22/2014 10:42 AM, Ed Huntress wrote:
On Sat, 22 Nov 2014 07:36:14 -0800 (PST), Sandarpan Mukherjee
wrote:

http://www.amazon.com/XMark-Commerci.../dp/B00JKM3BZU

The bar in the above link claims to have 240000 psi UTS and made out of a chrome-moly steel? Is it possible for such a high strength steel to be non-brittle enough for the application?

"Chrome-moly" usually means AISI 4340 steel or equivalent. 240 kpsi is
about the maximum, and elongation falls off sharply above 200 kpsi. At
225, it's down around 5/%.

Is that enough for your bar? I don't know. Maybe the real-world
application is no problem. At 5%, as a general matter in structural
applications, you begin to expect sudden failures. But maybe it's OK
for such a bar.

Be sure to watch the movie clip in the picture choices. Nice drop
tests that passed.

Martin

The video is interesting, but I was more impressed with the bending
test done in a machine. It's hard to tell what the actual load is on
the bar in those drop tests.

--
Ed Huntress

The actual load in the drop tests is easy to tell. Each plate is 45 lbs.

But that doesn't tell you what the load is on the bar, as a result of
being dropped with the weights on it.

For example, dropping it straight down and with the bar horizontal
imposes very little load on the bar.

Dropping it on a 45-degree angle to horizontal imposes a higher, but
unknown load. Note that the bar doesn't bend much in that test. The
load is not really very high, although it is more of an impact load.

--
Ed Huntress

http://www.roymech.co.uk/Useful_Tabl...cs_Impact.html

The above page gives approximate formulae to calculate impact stresses.

I really don't think that would answer it for you. When a bar is held
at 45 deg. to horizontal and dropped, the impact of the lower weights
is not transferred to the bar. It's absorbed by whatever is on the
ground.

The impact imposed by the upper weights depends on a complex set of
forces and deflections, which involve tracing the forces from the
upper weights, through the bar, to the lower weights, to where the
lower weights contact the ground.

Good luck with that. g

--
Ed Huntress

True, what you say, which is why I wrote approximate.

If you really want an engineering analysis of the loads and
deflections, this is a job for finite-element analysis (FEA). The
tools for doing that today are amazingly good. It would make a good
term paper for a mechanical engineering student.

However, what you have when you're done is a theoretical set of
behaviors based on nominal mechanical properties of the bar. You then
need to apply a safety factor, and that wouldn't be a piece of cake
for this job, either.

I don't know why you're making your own, but if I were doing it, I
would copy the material and dimensions of a commercial bar that is
known to be safe and successful. "Chrome-moly" is going to be 4340; I
would bet on it. But you could confirm it by asking the bar
manufacturer. I do that kind of thing all the time, as a writer in the
field. Most are forthcoming if it isn't about some proprietary issue,
and I can't imagine that this one is. They've publicly stated the
class of alloy; all you need to know is the last two numbers, which is
the carbon content. Again, that number is almost certainly 40.

Good luck with your project.

--
Ed Huntress

Thanks.

On Monday, 24 November 2014 21:51:08 UTC+5:30, Ed Huntress wrote:
On Mon, 24 Nov 2014 07:31:14 -0800 (PST), Sandarpan Mukherjee
wrote:

On Sunday, 23 November 2014 22:44:13 UTC+5:30, Ed Huntress wrote:
On Sun, 23 Nov 2014 08:48:09 -0800 (PST), Sandarpan Mukherjee
wrote:

On Sunday, 23 November 2014 12:32:13 UTC+5:30, Ed Huntress wrote:
On Sat, 22 Nov 2014 21:14:38 -0800 (PST), Sandarpan Mukherjee
wrote:

On Sunday, 23 November 2014 06:33:42 UTC+5:30, Ed Huntress wrote:
On Sat, 22 Nov 2014 18:25:32 -0600, Martin Eastburn
wrote:

On 11/22/2014 10:42 AM, Ed Huntress wrote:
On Sat, 22 Nov 2014 07:36:14 -0800 (PST), Sandarpan Mukherjee
wrote:

http://www.amazon.com/XMark-Commerci.../dp/B00JKM3BZU

The bar in the above link claims to have 240000 psi UTS and made out of a chrome-moly steel? Is it possible for such a high strength steel to be non-brittle enough for the application?

"Chrome-moly" usually means AISI 4340 steel or equivalent. 240 kpsi is
about the maximum, and elongation falls off sharply above 200 kpsi. At
225, it's down around 5/%.

Is that enough for your bar? I don't know. Maybe the real-world
application is no problem. At 5%, as a general matter in structural
applications, you begin to expect sudden failures. But maybe it's OK
for such a bar.

Be sure to watch the movie clip in the picture choices. Nice drop
tests that passed.

Martin

The video is interesting, but I was more impressed with the bending
test done in a machine. It's hard to tell what the actual load is on
the bar in those drop tests.

--
Ed Huntress

The actual load in the drop tests is easy to tell. Each plate is 45 lbs.

But that doesn't tell you what the load is on the bar, as a result of
being dropped with the weights on it.

For example, dropping it straight down and with the bar horizontal
imposes very little load on the bar.

Dropping it on a 45-degree angle to horizontal imposes a higher, but
unknown load. Note that the bar doesn't bend much in that test. The
load is not really very high, although it is more of an impact load..

--
Ed Huntress

http://www.roymech.co.uk/Useful_Tabl...cs_Impact.html

The above page gives approximate formulae to calculate impact stresses.

I really don't think that would answer it for you. When a bar is held
at 45 deg. to horizontal and dropped, the impact of the lower weights
is not transferred to the bar. It's absorbed by whatever is on the
ground.

The impact imposed by the upper weights depends on a complex set of
forces and deflections, which involve tracing the forces from the
upper weights, through the bar, to the lower weights, to where the
lower weights contact the ground.

Good luck with that. g

--
Ed Huntress

True, what you say, which is why I wrote approximate.

If you really want an engineering analysis of the loads and
deflections, this is a job for finite-element analysis (FEA). The
tools for doing that today are amazingly good. It would make a good
term paper for a mechanical engineering student.

However, what you have when you're done is a theoretical set of
behaviors based on nominal mechanical properties of the bar. You then
need to apply a safety factor, and that wouldn't be a piece of cake
for this job, either.

I don't know why you're making your own, but if I were doing it, I
would copy the material and dimensions of a commercial bar that is
known to be safe and successful. "Chrome-moly" is going to be 4340; I
would bet on it. But you could confirm it by asking the bar
manufacturer. I do that kind of thing all the time, as a writer in the
field. Most are forthcoming if it isn't about some proprietary issue,
and I can't imagine that this one is. They've publicly stated the
class of alloy; all you need to know is the last two numbers, which is
the carbon content. Again, that number is almost certainly 40.

Good luck with your project.

--
Ed Huntress

Also to answer your question why I'm making my own; all fitness stores here stock Chinese crap exclusively. The elite sponsored athletes train on imported Eleikos. Also a barbell is not a very complex piece of equipment. With access to materials, CNC machines and people who know how to machine I don't see why I should settle for bad equipment when, with a little "research" I can assimilate all the know how required to put together a decent bar. I said decent, not world class.

On Mon, 24 Nov 2014 10:07:13 -0800 (PST), Sandarpan Mukherjee
wrote:

On Monday, 24 November 2014 21:51:08 UTC+5:30, Ed Huntress wrote:
On Mon, 24 Nov 2014 07:31:14 -0800 (PST), Sandarpan Mukherjee
wrote:

On Sunday, 23 November 2014 22:44:13 UTC+5:30, Ed Huntress wrote:
On Sun, 23 Nov 2014 08:48:09 -0800 (PST), Sandarpan Mukherjee
wrote:

On Sunday, 23 November 2014 12:32:13 UTC+5:30, Ed Huntress wrote:
On Sat, 22 Nov 2014 21:14:38 -0800 (PST), Sandarpan Mukherjee
wrote:

On Sunday, 23 November 2014 06:33:42 UTC+5:30, Ed Huntress wrote:
On Sat, 22 Nov 2014 18:25:32 -0600, Martin Eastburn
wrote:

On 11/22/2014 10:42 AM, Ed Huntress wrote:
On Sat, 22 Nov 2014 07:36:14 -0800 (PST), Sandarpan Mukherjee
wrote:

http://www.amazon.com/XMark-Commerci.../dp/B00JKM3BZU

The bar in the above link claims to have 240000 psi UTS and made out of a chrome-moly steel? Is it possible for such a high strength steel to be non-brittle enough for the application?

"Chrome-moly" usually means AISI 4340 steel or equivalent. 240 kpsi is
about the maximum, and elongation falls off sharply above 200 kpsi. At
225, it's down around 5/%.

Is that enough for your bar? I don't know. Maybe the real-world
application is no problem. At 5%, as a general matter in structural
applications, you begin to expect sudden failures. But maybe it's OK
for such a bar.

Be sure to watch the movie clip in the picture choices. Nice drop
tests that passed.

Martin

The video is interesting, but I was more impressed with the bending
test done in a machine. It's hard to tell what the actual load is on
the bar in those drop tests.

--
Ed Huntress

The actual load in the drop tests is easy to tell. Each plate is 45 lbs.

But that doesn't tell you what the load is on the bar, as a result of
being dropped with the weights on it.

For example, dropping it straight down and with the bar horizontal
imposes very little load on the bar.

Dropping it on a 45-degree angle to horizontal imposes a higher, but
unknown load. Note that the bar doesn't bend much in that test. The
load is not really very high, although it is more of an impact load.

--
Ed Huntress

http://www.roymech.co.uk/Useful_Tabl...cs_Impact.html

The above page gives approximate formulae to calculate impact stresses.

I really don't think that would answer it for you. When a bar is held
at 45 deg. to horizontal and dropped, the impact of the lower weights
is not transferred to the bar. It's absorbed by whatever is on the
ground.

The impact imposed by the upper weights depends on a complex set of
forces and deflections, which involve tracing the forces from the
upper weights, through the bar, to the lower weights, to where the
lower weights contact the ground.

Good luck with that. g

--
Ed Huntress

True, what you say, which is why I wrote approximate.

If you really want an engineering analysis of the loads and
deflections, this is a job for finite-element analysis (FEA). The
tools for doing that today are amazingly good. It would make a good
term paper for a mechanical engineering student.

However, what you have when you're done is a theoretical set of
behaviors based on nominal mechanical properties of the bar. You then
need to apply a safety factor, and that wouldn't be a piece of cake
for this job, either.

I don't know why you're making your own, but if I were doing it, I
would copy the material and dimensions of a commercial bar that is
known to be safe and successful. "Chrome-moly" is going to be 4340; I
would bet on it. But you could confirm it by asking the bar
manufacturer. I do that kind of thing all the time, as a writer in the
field. Most are forthcoming if it isn't about some proprietary issue,
and I can't imagine that this one is. They've publicly stated the
class of alloy; all you need to know is the last two numbers, which is
the carbon content. Again, that number is almost certainly 40.

Good luck with your project.

--
Ed Huntress

Also to answer your question why I'm making my own; all fitness stores here stock Chinese crap exclusively. The elite sponsored athletes train on imported Eleikos. Also a barbell is not a very complex piece of equipment. With access to materials, CNC machines and people who know how to machine I don't see why I should settle for bad equipment when, with a little "research" I can assimilate all the know how required to put together a decent bar. I said decent, not world class.

Well, if price is the issue, you should be able to beat those prices I
saw in the links. The trickiest part of the whole project will be the
heat treatment. If you have a really good commercial heat-treat shop,
they should be able to do it. It's cookbook. But, considering that
you're pushing the steel near to its limits of strength, it has to be
done right.

--
Ed Huntress

On Mon, 24 Nov 2014 07:32:45 -0800 (PST), Sandarpan Mukherjee
wrote:

On Monday, 24 November 2014 00:09:02 UTC+5:30, Jim Wilkins wrote:
"Sandarpan Mukherjee" wrote in message
...
...
Yes. What I would love to know is though, what is the elongation %
and reduction in area of the bars at the given strength. Something
no manufacturer is willing to tell.

A failed, discarded bar might.

If you plan to make these things you need a way to proof test them
anyway.

And therein lies the problem. The driving force behind me wanting to make a bar in the first place is a complete lack of quality equipment in my country. Elite athletes all import Eleikos. However they are sponsored. I am not.

Not to be insulting, but how much can you lift? do you really need a
bar that is made of 250,000 psi steel to handle the weight that you
can lift at your present stage of development?

--
cheers,

John D.Slocomb

On Tuesday, 25 November 2014 06:37:13 UTC+5:30, John D. Slocomb wrote:
On Mon, 24 Nov 2014 07:32:45 -0800 (PST), Sandarpan Mukherjee
wrote:

On Monday, 24 November 2014 00:09:02 UTC+5:30, Jim Wilkins wrote:
"Sandarpan Mukherjee" wrote in message
...
...
Yes. What I would love to know is though, what is the elongation %
and reduction in area of the bars at the given strength. Something
no manufacturer is willing to tell.

A failed, discarded bar might.

If you plan to make these things you need a way to proof test them
anyway.

And therein lies the problem. The driving force behind me wanting to make a bar in the first place is a complete lack of quality equipment in my country. Elite athletes all import Eleikos. However they are sponsored. I am not.

Not to be insulting, but how much can you lift? do you really need a
bar that is made of 250,000 psi steel to handle the weight that you
can lift at your present stage of development?

--
cheers,

John D.Slocomb

I can squat 315 lbs and deadlift 400. Not nearly enough to test 200000 psi. But what happens if I accidentally drop a loaded bar on my power rack safety rods? Will the bar survive the severe bending impact? That is when a stronger bar proves its strength.

On Sunday, November 9, 2014 at 11:17:43 PM UTC+5:30, wrote:
As mentioned in the subject, I'm looking for steel suitable to be used to make an Olympic barbell, 2.2m long and 28mm in diameter. I'm torn between chrome-moly steel and spring steel. Again I'm not a metallurgist and know very little about these things. The bar will be at least 190000 psi tensile strength with 170000 psi yield strength. I'm also looking for decent machining characteristics so that I can put a knurl on it and cut grooves to attach sleeves.

Here are some steels I've thought about

SAE 4340 (Heat treated to the required Tensile strength)
SAE 4140
EN 47??

Thanks


I think we need to buy one branded bar and have to check chemical properties of shaft material..
As we have to do all cnc work or lathe work on Shaft like knurling,turning,grooving before heat treating
But
If we do heat treat bar can bend due to heat then after we need to remove bend on bend remove press machine
or
it take alot of time and money but if we complete this all process ..This bar ll be very easy to make in quantity.

As we know In India EN19 to EN 24 is available but its impossible to heat 7 ft shaft in oven...Oven should be very big.


For more info you can reply me.

On Tue, 30 Mar 2021 21:27:52 -0700 (PDT), Padmanabh Jadhav
wrote:

On Sunday, November 9, 2014 at 11:17:43 PM UTC+5:30, wrote:
As mentioned in the subject, I'm looking for steel suitable to be used to make an Olympic barbell, 2.2m long and 28mm in diameter. I'm torn between chrome-moly steel and spring steel. Again I'm not a metallurgist and know very little about these things. The bar will be at least 190000 psi tensile strength with 170000 psi yield strength. I'm also looking for decent machining characteristics so that I can put a knurl on it and cut grooves to attach sleeves.

Here are some steels I've thought about

SAE 4340 (Heat treated to the required Tensile strength)
SAE 4140
EN 47??

Thanks


I think we need to buy one branded bar and have to check chemical properties of shaft material..
As we have to do all cnc work or lathe work on Shaft like knurling,turning,grooving before heat treating
But
If we do heat treat bar can bend due to heat then after we need to remove bend on bend remove press machine
or
it take alot of time and money but if we complete this all process ..This bar ll be very easy to make in quantity.

As we know In India EN19 to EN 24 is available but its impossible to heat 7 ft shaft in oven...Oven should be very big.


For more info you can reply me.
My knowledge is limited to bars I have purchased at yard sales to be
used as a source of raw material. These bars seem to be made erom the
nastiest material imaginable; the best way to machine them being to
use an angle grinder!

On Thu, 01 Apr 2021 00:04:07 -0400, Gerry
wrote:

On Tue, 30 Mar 2021 21:27:52 -0700 (PDT), Padmanabh Jadhav
wrote:

On Sunday, November 9, 2014 at 11:17:43 PM UTC+5:30, wrote:
As mentioned in the subject, I'm looking for steel suitable to be used to make an Olympic barbell, 2.2m long and 28mm in diameter. I'm torn between chrome-moly steel and spring steel. Again I'm not a metallurgist and know very little about these things. The bar will be at least 190000 psi tensile strength with 170000 psi yield strength. I'm also looking for decent machining characteristics so that I can put a knurl on it and cut grooves to attach sleeves.

Here are some steels I've thought about

SAE 4340 (Heat treated to the required Tensile strength)
SAE 4140
EN 47??

Thanks


I think we need to buy one branded bar and have to check chemical properties of shaft material..
As we have to do all cnc work or lathe work on Shaft like knurling,turning,grooving before heat treating
But
If we do heat treat bar can bend due to heat then after we need to remove bend on bend remove press machine
or
it take alot of time and money but if we complete this all process ..This bar ll be very easy to make in quantity.

As we know In India EN19 to EN 24 is available but its impossible to heat 7 ft shaft in oven...Oven should be very big.


For more info you can reply me.
My knowledge is limited to bars I have purchased at yard sales to be
used as a source of raw material. These bars seem to be made erom the
nastiest material imaginable; the best way to machine them being to
use an angle grinder!

A quick look at the olympic type bars available seem to show an
olympic style bar stated to be "120,000 lbs" tensile strength. If they
actually meant 120,000 lbs/inch square then 4140 (normalized at 810
degrees C) will have a tensile strength of 147,938 psi and 4140
annealed is about 94,000 psi. So 4140 should work.

Companies sell heat treated bar stock
https://www.specialtysteel.com/alloy...-heat-treated/
for example sells 4140 hot rolled with Brinnell of 269/341BHN and a
tensile strength of 156,000 psi. Brinnell Hardness 271 = RC 28.8 and
342 = RC 26.6

--
Cheers,

John B.