I bought a bunch of 1-1/2" bore x 3/4" stroke single-acting pull-off air
cylinders to use for clamping fixtures. They are perfect with the
spring force to hold the part but the air input is on the front end.
The back cap can be drilled and tapped 1/8" NPT and a fitting installed.
This will make them push-type. BUT...there is a vent hole in the
stainless tube at the back of the cylinder that must be plugged. I'm
thinking of a hose clamp and a piece of rubber unless there's a better
way. If I could take the cylinder apart I could TIG the hole closed but
these are sealed, throw-away cylinders cylinders. They ARE worth
modifying because I bought them for $4 each and they retail for $60. I
need 16 of them modified.

sell them on ebay and buy proper cylinders.

i

On 2011-07-27, Tom Gardner mars@tacks wrote:
I bought a bunch of 1-1/2" bore x 3/4" stroke single-acting pull-off air
cylinders to use for clamping fixtures. They are perfect with the
spring force to hold the part but the air input is on the front end.
The back cap can be drilled and tapped 1/8" NPT and a fitting installed.
This will make them push-type. BUT...there is a vent hole in the
stainless tube at the back of the cylinder that must be plugged. I'm
thinking of a hose clamp and a piece of rubber unless there's a better
way. If I could take the cylinder apart I could TIG the hole closed but
these are sealed, throw-away cylinders cylinders. They ARE worth
modifying because I bought them for $4 each and they retail for $60. I
need 16 of them modified.

On 7/27/2011 12:53 PM, Ignoramus31510 wrote:
sell them on ebay and buy proper cylinders.

i\
Hmmm, $64 verses $960. I'll use the hose clamps and innertube.

On 2011-07-27, Tom Gardner mars@tacks wrote:
On 7/27/2011 12:53 PM, Ignoramus31510 wrote:
sell them on ebay and buy proper cylinders.

i\
Hmmm, $64 verses $960. I'll use the hose clamps and innertube.

These cylinders cost next to nothing on ebay.

i

Tom Gardner wrote:

I bought a bunch of 1-1/2" bore x 3/4" stroke single-acting pull-off air
cylinders to use for clamping fixtures. They are perfect with the
spring force to hold the part but the air input is on the front end.
The back cap can be drilled and tapped 1/8" NPT and a fitting installed.
This will make them push-type. BUT...there is a vent hole in the
stainless tube at the back of the cylinder that must be plugged. I'm
thinking of a hose clamp and a piece of rubber unless there's a better
way. If I could take the cylinder apart I could TIG the hole closed but
these are sealed, throw-away cylinders cylinders. They ARE worth
modifying because I bought them for $4 each and they retail for $60. I
need 16 of them modified.

If you can hold the piston and thus the seals away from the hole area I
bet you can TIG them and dump them in cold water before too much heat
gets neat the seals.

"Pete C." wrote in message
.com...

Tom Gardner wrote:

I bought a bunch of 1-1/2" bore x 3/4" stroke single-acting pull-off air
cylinders to use for clamping fixtures. They are perfect with the
spring force to hold the part but the air input is on the front end.
The back cap can be drilled and tapped 1/8" NPT and a fitting installed.
This will make them push-type. BUT...there is a vent hole in the
stainless tube at the back of the cylinder that must be plugged. I'm
thinking of a hose clamp and a piece of rubber unless there's a better
way. If I could take the cylinder apart I could TIG the hole closed but
these are sealed, throw-away cylinders cylinders. They ARE worth
modifying because I bought them for $4 each and they retail for $60. I
need 16 of them modified.

If you can hold the piston and thus the seals away from the hole area I
bet you can TIG them and dump them in cold water before too much heat
gets neat the seals.

The piston IS pushed away by the spring, these are pull-off cylinders so the
spring naturally extends them. I might try the TIG, thanks!

"Ignoramus31510" wrote in message
news
On 2011-07-27, Tom Gardner mars@tacks wrote:
On 7/27/2011 12:53 PM, Ignoramus31510 wrote:
sell them on ebay and buy proper cylinders.

i\
Hmmm, $64 verses $960. I'll use the hose clamps and innertube.

These cylinders cost next to nothing on ebay.

i

I couldn't find them in the right size or quantity.

"Tom Gardner" mars@tacks wrote in message
news
I bought a bunch of 1-1/2" bore x 3/4" stroke single-acting pull-off air
cylinders to use for clamping fixtures. They are perfect with the
spring force to hold the part but the air input is on the front end.
The back cap can be drilled and tapped 1/8" NPT and a fitting installed.
This will make them push-type. BUT...there is a vent hole in the
stainless tube at the back of the cylinder that must be plugged. I'm
thinking of a hose clamp and a piece of rubber unless there's a better
way. If I could take the cylinder apart I could TIG the hole closed but
these are sealed, throw-away cylinders cylinders. They ARE worth
modifying because I bought them for $4 each and they retail for $60. I
need 16 of them modified.

You may want to test 1 first to be sure the piston seal is bidirectional.
Art

"Tom Gardner" fired this volley in
news
The piston IS pushed away by the spring, these are pull-off cylinders
so the spring naturally extends them. I might try the TIG, thanks!

Tig can concentrate its heat in a small area. Wrap the whole body of the
cylinder in a wet cloth, or better, suspend it all but the end-cap in a
vessel of water, then weld away.

LLoyd

On 07/27/2011 01:38 PM, Artemus wrote:
"Tom Gardner"mars@tacks wrote in message
news
I bought a bunch of 1-1/2" bore x 3/4" stroke single-acting pull-off air
cylinders to use for clamping fixtures. They are perfect with the
spring force to hold the part but the air input is on the front end.
The back cap can be drilled and tapped 1/8" NPT and a fitting installed.
This will make them push-type. BUT...there is a vent hole in the
stainless tube at the back of the cylinder that must be plugged. I'm
thinking of a hose clamp and a piece of rubber unless there's a better
way. If I could take the cylinder apart I could TIG the hole closed but
these are sealed, throw-away cylinders cylinders. They ARE worth
modifying because I bought them for $4 each and they retail for $60. I
need 16 of them modified.

You may want to test 1 first to be sure the piston seal is bidirectional.
Art


Yes. Very sound idea, as they are usually not bidirectional. That would
cost a penny or two more for the seal...

bill

On 7/27/2011 5:45 PM, Bill Martin wrote:
On 07/27/2011 01:38 PM, Artemus wrote:
"Tom Gardner"mars@tacks wrote in message
news
I bought a bunch of 1-1/2" bore x 3/4" stroke single-acting pull-off air
cylinders to use for clamping fixtures. They are perfect with the
spring force to hold the part but the air input is on the front end.
The back cap can be drilled and tapped 1/8" NPT and a fitting installed.
This will make them push-type. BUT...there is a vent hole in the
stainless tube at the back of the cylinder that must be plugged. I'm
thinking of a hose clamp and a piece of rubber unless there's a better
way. If I could take the cylinder apart I could TIG the hole closed but
these are sealed, throw-away cylinders cylinders. They ARE worth
modifying because I bought them for $4 each and they retail for $60. I
need 16 of them modified.

You may want to test 1 first to be sure the piston seal is bidirectional.
Art


Yes. Very sound idea, as they are usually not bidirectional. That would
cost a penny or two more for the seal...

bill

Yes, they are standard bi-directional pistons. I installed a fitting on
the back of one and used a hose clamp and a strip of sheet rubber. It
works perfectly! I was hoping for a more elegant solution but I ain't
too proud to use the hose clamp fix.

Tom Gardner wrote:

I bought a bunch of 1-1/2" bore x 3/4" stroke single-acting pull-off air
cylinders to use for clamping fixtures. They are perfect with the
spring force to hold the part but the air input is on the front end.
The back cap can be drilled and tapped 1/8" NPT and a fitting installed.
This will make them push-type. BUT...there is a vent hole in the
stainless tube at the back of the cylinder that must be plugged. I'm
thinking of a hose clamp and a piece of rubber unless there's a better
way. If I could take the cylinder apart I could TIG the hole closed but
these are sealed, throw-away cylinders cylinders. They ARE worth
modifying because I bought them for $4 each and they retail for $60. I
need 16 of them modified.


How big is the hole? Could you thread it and use a plug? A photo
would help.


--
It's easy to think outside the box, when you have a cutting torch.

On 7/28/2011 3:00 AM, Michael A. Terrell wrote:

Tom Gardner wrote:

I bought a bunch of 1-1/2" bore x 3/4" stroke single-acting pull-off air
cylinders to use for clamping fixtures. They are perfect with the
spring force to hold the part but the air input is on the front end.
The back cap can be drilled and tapped 1/8" NPT and a fitting installed.
This will make them push-type. BUT...there is a vent hole in the
stainless tube at the back of the cylinder that must be plugged. I'm
thinking of a hose clamp and a piece of rubber unless there's a better
way. If I could take the cylinder apart I could TIG the hole closed but
these are sealed, throw-away cylinders cylinders. They ARE worth
modifying because I bought them for $4 each and they retail for $60. I
need 16 of them modified.


How big is the hole? Could you thread it and use a plug? A photo
would help.



Probably a standard Bimba vent hole, about 3/32" and the wall is about
1/32"thick. I was thinking the same thing, a #8 with a dab of goo.

Tom Gardner wrote:

On 7/28/2011 3:00 AM, Michael A. Terrell wrote:

Tom Gardner wrote:

I bought a bunch of 1-1/2" bore x 3/4" stroke single-acting pull-off air
cylinders to use for clamping fixtures. They are perfect with the
spring force to hold the part but the air input is on the front end.
The back cap can be drilled and tapped 1/8" NPT and a fitting installed.
This will make them push-type. BUT...there is a vent hole in the
stainless tube at the back of the cylinder that must be plugged. I'm
thinking of a hose clamp and a piece of rubber unless there's a better
way. If I could take the cylinder apart I could TIG the hole closed but
these are sealed, throw-away cylinders cylinders. They ARE worth
modifying because I bought them for $4 each and they retail for $60. I
need 16 of them modified.


How big is the hole? Could you thread it and use a plug? A photo
would help.



Probably a standard Bimba vent hole, about 3/32" and the wall is about
1/32"thick. I was thinking the same thing, a #8 with a dab of goo.


It would make it easy to convert to another use, later on and
wouldn't take long to do the whole batch.


--
It's easy to think outside the box, when you have a cutting torch.

On 7/28/2011 11:06 AM, Michael A. Terrell wrote:

Tom Gardner wrote:

On 7/28/2011 3:00 AM, Michael A. Terrell wrote:

Tom Gardner wrote:

I bought a bunch of 1-1/2" bore x 3/4" stroke single-acting pull-off air
cylinders to use for clamping fixtures. They are perfect with the
spring force to hold the part but the air input is on the front end.
The back cap can be drilled and tapped 1/8" NPT and a fitting installed.
This will make them push-type. BUT...there is a vent hole in the
stainless tube at the back of the cylinder that must be plugged. I'm
thinking of a hose clamp and a piece of rubber unless there's a better
way. If I could take the cylinder apart I could TIG the hole closed but
these are sealed, throw-away cylinders cylinders. They ARE worth
modifying because I bought them for $4 each and they retail for $60. I
need 16 of them modified.


How big is the hole? Could you thread it and use a plug? A photo
would help.



Probably a standard Bimba vent hole, about 3/32" and the wall is about
1/32"thick. I was thinking the same thing, a #8 with a dab of goo.


It would make it easy to convert to another use, later on and
wouldn't take long to do the whole batch.



I bought ten on the first round because it was the sweet spot for
shipping. I think I'll get away with eight because they are 1-1/2" bore
with plenty of clamping power. There are four block holders on the
machine and each holds two blocks with a cylinder for each block. The
machine cycles from one side of each holder to the other and the
finished block is released then the operator moves that block to the
fill station holder from the drill station. With ten cylinders, I'll
only have two spares and they might be impossible to get years from now
so I will buy another ten for future use...they WILL fail at some time.
I should buy even more for other projects but where do you stop?

Tom Gardner wrote:

On 7/28/2011 11:06 AM, Michael A. Terrell wrote:

Tom Gardner wrote:

On 7/28/2011 3:00 AM, Michael A. Terrell wrote:

Tom Gardner wrote:

I bought a bunch of 1-1/2" bore x 3/4" stroke single-acting pull-off air
cylinders to use for clamping fixtures. They are perfect with the
spring force to hold the part but the air input is on the front end.
The back cap can be drilled and tapped 1/8" NPT and a fitting installed.
This will make them push-type. BUT...there is a vent hole in the
stainless tube at the back of the cylinder that must be plugged. I'm
thinking of a hose clamp and a piece of rubber unless there's a better
way. If I could take the cylinder apart I could TIG the hole closed but
these are sealed, throw-away cylinders cylinders. They ARE worth
modifying because I bought them for $4 each and they retail for $60. I
need 16 of them modified.


How big is the hole? Could you thread it and use a plug? A photo
would help.



Probably a standard Bimba vent hole, about 3/32" and the wall is about
1/32"thick. I was thinking the same thing, a #8 with a dab of goo.


It would make it easy to convert to another use, later on and
wouldn't take long to do the whole batch.



I bought ten on the first round because it was the sweet spot for
shipping. I think I'll get away with eight because they are 1-1/2" bore
with plenty of clamping power. There are four block holders on the
machine and each holds two blocks with a cylinder for each block. The
machine cycles from one side of each holder to the other and the
finished block is released then the operator moves that block to the
fill station holder from the drill station. With ten cylinders, I'll
only have two spares and they might be impossible to get years from now
so I will buy another ten for future use...they WILL fail at some time.
I should buy even more for other projects but where do you stop?


Will you need to duplicate that machine some day? I look at the
ecpected life, and how long I intend to keep omething, VS. the current
cost of spares.


--
It's easy to think outside the box, when you have a cutting torch.