Hi all,

This autumn I'm going to build an enclosure to house capacitors,
contactors and thermal circuit breakers as part of my phase convertor.
As I mentioned in a previous post, it needs to be strong because the
transformer will be mounted on the side, so I'm going to use 5 mm plate
and weld it together (a bit like a pole pig tank). I might make the back
plate where the transformer hangs a bit thicker. The top of the
enclosure will be removable, with a flange around the edge and a sealing
gasket underneath. I want to secure the top with stainless domed nuts,
because they look good. So I need a way of attaching studs to the
enclosure. Two problems: I don't know where I can buy studs (although I
can buy all-thread) and I'm a bit doubtful about only having a 5 mm
length of M8 or M10 thread. I do need to screw these nuts down
reasonably tight in order to seal the enclosure, and I had also wondered
about replacing two domed nuts with eye nuts for lifting, so they need
to be strong. One idea I had was to thread the holes and screw a bolt in
from underneath, so that the threaded section sticks up, then tighten
the bolt against the plate like a locknut. I know this might seem like
an academic discussion, but I want to do a good job. I'm interested to
know how you guys would do it.

Best wishes,

Chris

"Christopher Tidy" wrote in message
...
Hi all,

This autumn I'm going to build an enclosure to house capacitors,
contactors and thermal circuit breakers as part of my phase convertor.
As I mentioned in a previous post, it needs to be strong because the
transformer will be mounted on the side, so I'm going to use 5 mm plate
and weld it together (a bit like a pole pig tank). I might make the back
plate where the transformer hangs a bit thicker. The top of the
enclosure will be removable, with a flange around the edge and a sealing
gasket underneath. I want to secure the top with stainless domed nuts,
because they look good. So I need a way of attaching studs to the
enclosure. Two problems: I don't know where I can buy studs (although I
can buy all-thread) and I'm a bit doubtful about only having a 5 mm
length of M8 or M10 thread. I do need to screw these nuts down
reasonably tight in order to seal the enclosure, and I had also wondered
about replacing two domed nuts with eye nuts for lifting, so they need
to be strong. One idea I had was to thread the holes and screw a bolt in
from underneath, so that the threaded section sticks up, then tighten
the bolt against the plate like a locknut. I know this might seem like
an academic discussion, but I want to do a good job. I'm interested to
know how you guys would do it.

Best wishes,

Chris


5 mm thick plate should be ample unless the transformer is very heavy. And
the rule of thumb on threads is that you must engage at least four threads
for maximum strength. The first and last bit of thread, of course, is a
little questionable. But a coarse thread M6 or a fine thread M8 (1.0 thread
pitch) should engage more than four full threads in a 5 mm. plate. A coarse
thread M8 or a fine thread M10 (1.25 thread pitch) would be right on the
boarderline. This doesn't mean that the threads would necessarily let go,
simply that the threads will fail before the fastener...

Jerry

Jerry Foster wrote:
"Christopher Tidy" wrote in message
...

Hi all,

This autumn I'm going to build an enclosure to house capacitors,
contactors and thermal circuit breakers as part of my phase convertor.
As I mentioned in a previous post, it needs to be strong because the
transformer will be mounted on the side, so I'm going to use 5 mm plate
and weld it together (a bit like a pole pig tank). I might make the back
plate where the transformer hangs a bit thicker. The top of the
enclosure will be removable, with a flange around the edge and a sealing
gasket underneath. I want to secure the top with stainless domed nuts,
because they look good. So I need a way of attaching studs to the
enclosure. Two problems: I don't know where I can buy studs (although I
can buy all-thread) and I'm a bit doubtful about only having a 5 mm
length of M8 or M10 thread. I do need to screw these nuts down
reasonably tight in order to seal the enclosure, and I had also wondered
about replacing two domed nuts with eye nuts for lifting, so they need
to be strong. One idea I had was to thread the holes and screw a bolt in
from underneath, so that the threaded section sticks up, then tighten
the bolt against the plate like a locknut. I know this might seem like
an academic discussion, but I want to do a good job. I'm interested to
know how you guys would do it.

Best wishes,

Chris



5 mm thick plate should be ample unless the transformer is very heavy. And
the rule of thumb on threads is that you must engage at least four threads
for maximum strength. The first and last bit of thread, of course, is a
little questionable. But a coarse thread M6 or a fine thread M8 (1.0 thread
pitch) should engage more than four full threads in a 5 mm. plate. A coarse
thread M8 or a fine thread M10 (1.25 thread pitch) would be right on the
boarderline. This doesn't mean that the threads would necessarily let go,
simply that the threads will fail before the fastener...

Thanks for the information. That's pretty much what I thought - 5 mm is
borderline. When designing things in the past I've aimed to make the
length of the thread at least the same as the bolt diameter.

Chris

On Sat, 17 Sep 2005 22:01:37 +0000 (UTC), Christopher Tidy
wrote:

Hi all,

This autumn I'm going to build an enclosure to house capacitors,
contactors and thermal circuit breakers as part of my phase convertor.
As I mentioned in a previous post, it needs to be strong because the
transformer will be mounted on the side, so I'm going to use 5 mm plate
and weld it together (a bit like a pole pig tank). I might make the back
plate where the transformer hangs a bit thicker. The top of the
enclosure will be removable, with a flange around the edge and a sealing
gasket underneath. I want to secure the top with stainless domed nuts,
because they look good. So I need a way of attaching studs to the
enclosure. Two problems: I don't know where I can buy studs (although I
can buy all-thread) and I'm a bit doubtful about only having a 5 mm
length of M8 or M10 thread. I do need to screw these nuts down
reasonably tight in order to seal the enclosure, and I had also wondered
about replacing two domed nuts with eye nuts for lifting, so they need
to be strong. One idea I had was to thread the holes and screw a bolt in
from underneath, so that the threaded section sticks up, then tighten
the bolt against the plate like a locknut. I know this might seem like
an academic discussion, but I want to do a good job. I'm interested to
know how you guys would do it.

Best wishes,

Chris
Greetings Chris,
Some auto parts stores and some good hardware stores sell heat treated
studs. Some studs will have a fine thread on one end and coarse on the
other. With 5mm thick plate and 8 or 10 mm threads I'd use a bolt
going through the plate. If you do not want the head of a screw
protruding inside the enclosure then a flat head screw will work. Tap
and c'sink the plate and Loctite the screws into the plate.
ERS

plate where the transformer hangs a bit thicker. The top of the
enclosure will be removable, with a flange around the edge and a
sealing gasket underneath. I want to secure the top with stainless
domed nuts, because they look good. So I need a way of attaching studs
to the enclosure. Two problems: I don't know where I can buy studs
(although I

Press in PEM-type studs then use your cap nuts. Where to buy them
depends on where you live. In Maryland, USA,
http://www.hitechfasteners.com/ is a good source for us - I'm sure you
can find them local to you.

--
Regards,
Carl Ijames carl.ijames at verizon.net

Just buy a NEMA enclosure. hey will hold heavy transformers. I see them
on Ebay and of course they are available in Home Depot and the like.
Bob AZ

Eric R Snow wrote:
On Sat, 17 Sep 2005 22:01:37 +0000 (UTC), Christopher Tidy
wrote:


Hi all,

This autumn I'm going to build an enclosure to house capacitors,
contactors and thermal circuit breakers as part of my phase convertor.
As I mentioned in a previous post, it needs to be strong because the
transformer will be mounted on the side, so I'm going to use 5 mm plate
and weld it together (a bit like a pole pig tank). I might make the back
plate where the transformer hangs a bit thicker. The top of the
enclosure will be removable, with a flange around the edge and a sealing
gasket underneath. I want to secure the top with stainless domed nuts,
because they look good. So I need a way of attaching studs to the
enclosure. Two problems: I don't know where I can buy studs (although I
can buy all-thread) and I'm a bit doubtful about only having a 5 mm
length of M8 or M10 thread. I do need to screw these nuts down
reasonably tight in order to seal the enclosure, and I had also wondered
about replacing two domed nuts with eye nuts for lifting, so they need
to be strong. One idea I had was to thread the holes and screw a bolt in

from underneath, so that the threaded section sticks up, then tighten

the bolt against the plate like a locknut. I know this might seem like
an academic discussion, but I want to do a good job. I'm interested to
know how you guys would do it.

Best wishes,

Chris

Greetings Chris,
Some auto parts stores and some good hardware stores sell heat treated
studs. Some studs will have a fine thread on one end and coarse on the
other. With 5mm thick plate and 8 or 10 mm threads I'd use a bolt
going through the plate. If you do not want the head of a screw
protruding inside the enclosure then a flat head screw will work. Tap
and c'sink the plate and Loctite the screws into the plate.
ERS

Thanks for all the suggestions. If I can't find any studs easily, I
reckon I'll tap the holes, screw in bolts from the underside and tighten
them against the plate. The heads don't matter, and I can't really
countersink the holes as I'm going to drill them after the box had been
assembled. My only slight concern was that the bolts might come undone
as I tighten the nuts, but I think this is pretty unlikely, right?

Best wishes,

Chris

Eric R Snow wrote:
On Sat, 17 Sep 2005 22:01:37 +0000 (UTC), Christopher Tidy
wrote:


Hi all,

This autumn I'm going to build an enclosure to house capacitors,
contactors and thermal circuit breakers as part of my phase convertor.
As I mentioned in a previous post, it needs to be strong because the
transformer will be mounted on the side, so I'm going to use 5 mm plate
and weld it together (a bit like a pole pig tank). I might make the back
plate where the transformer hangs a bit thicker. The top of the
enclosure will be removable, with a flange around the edge and a sealing
gasket underneath. I want to secure the top with stainless domed nuts,
because they look good. So I need a way of attaching studs to the
enclosure. Two problems: I don't know where I can buy studs (although I
can buy all-thread) and I'm a bit doubtful about only having a 5 mm
length of M8 or M10 thread. I do need to screw these nuts down
reasonably tight in order to seal the enclosure, and I had also wondered
about replacing two domed nuts with eye nuts for lifting, so they need
to be strong. One idea I had was to thread the holes and screw a bolt in

from underneath, so that the threaded section sticks up, then tighten

the bolt against the plate like a locknut. I know this might seem like
an academic discussion, but I want to do a good job. I'm interested to
know how you guys would do it.

Best wishes,

Chris

Greetings Chris,
Some auto parts stores and some good hardware stores sell heat treated
studs. Some studs will have a fine thread on one end and coarse on the
other. With 5mm thick plate and 8 or 10 mm threads I'd use a bolt
going through the plate. If you do not want the head of a screw
protruding inside the enclosure then a flat head screw will work. Tap
and c'sink the plate and Loctite the screws into the plate.
ERS

Thanks for all the suggestions. If I can't find any studs easily, I
reckon I'll tap the holes, screw in bolts from the underside and tighten
them against the plate. The heads don't matter, and I can't really
countersink the holes as I'm going to drill them after the box had been
assembled. My only slight concern was that the bolts might come undone
as I tighten the nuts, but I think this is pretty unlikely, right?

Best wishes,

Chris

On Sun, 18 Sep 2005 15:42:20 +0000 (UTC), Christopher Tidy
wrote:

Eric R Snow wrote:
On Sat, 17 Sep 2005 22:01:37 +0000 (UTC), Christopher Tidy
wrote:


Hi all,

This autumn I'm going to build an enclosure to house capacitors,
contactors and thermal circuit breakers as part of my phase convertor.
As I mentioned in a previous post, it needs to be strong because the
transformer will be mounted on the side, so I'm going to use 5 mm plate
and weld it together (a bit like a pole pig tank). I might make the back
plate where the transformer hangs a bit thicker. The top of the
enclosure will be removable, with a flange around the edge and a sealing
gasket underneath. I want to secure the top with stainless domed nuts,
because they look good. So I need a way of attaching studs to the
enclosure. Two problems: I don't know where I can buy studs (although I
can buy all-thread) and I'm a bit doubtful about only having a 5 mm
length of M8 or M10 thread. I do need to screw these nuts down
reasonably tight in order to seal the enclosure, and I had also wondered
about replacing two domed nuts with eye nuts for lifting, so they need
to be strong. One idea I had was to thread the holes and screw a bolt in

from underneath, so that the threaded section sticks up, then tighten

the bolt against the plate like a locknut. I know this might seem like
an academic discussion, but I want to do a good job. I'm interested to
know how you guys would do it.

Best wishes,

Chris

Greetings Chris,
Some auto parts stores and some good hardware stores sell heat treated
studs. Some studs will have a fine thread on one end and coarse on the
other. With 5mm thick plate and 8 or 10 mm threads I'd use a bolt
going through the plate. If you do not want the head of a screw
protruding inside the enclosure then a flat head screw will work. Tap
and c'sink the plate and Loctite the screws into the plate.
ERS

Thanks for all the suggestions. If I can't find any studs easily, I
reckon I'll tap the holes, screw in bolts from the underside and tighten
them against the plate. The heads don't matter, and I can't really
countersink the holes as I'm going to drill them after the box had been
assembled. My only slight concern was that the bolts might come undone
as I tighten the nuts, but I think this is pretty unlikely, right?

Best wishes,

Chris
If the bolts are tight against the plate they most likely will not
back out. If loctite is used the chance for them to backout is
miniscule.
ERS