Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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  #1   Report Post  
 
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Default Pressing drill rod into brass.

I make spinning tools for a lady who owns a sheep farm. They look like
a long slender top with a 3/32" drill rod shaft and a 1" diameter x
..100 thick brass flywheel to generate the needed inertia to keep it
spinning. These are for spinning cotton fibers.

The problem is that some of them do not stay fixed in the hole. The
hole is drilled and then reamed .0005 undersize and then the brass is
tapped onto the shaft using another piece of brass the same diameter
with a hole drilled in the center for the shaft to pass through. I
think some of the brass is being displaced by the much harder steel
shaft and it will spin on the shaft.

I have tried everything from Loctite to Super Glue to Epoxy. Loctite
was hit and miss even thought the brass and shaft were thouroughly
cleaned prior to assembly. Super Glue was the same but left an opaque
film. Epoxy was too unsightly and the customer did not like it.

I know that a shrink fit would be best but too much heat discolors the
brass. All I have to heat the brass is a toaster oven I use for
tempering. It was a max temp of around 500 degrees F. The other problem
is how to shrink the drill rod. I do not want to have to deal with dry
ice or liquid nitrogen to do this. It is too expensive to get those and
the profit margin on these is not there.

Any suggestion on how to put these together would be greatly
appreciated. The bonding agent cannot be seen on the outside of the
piece. I also tried soldering but it did not look too good.

Thanks, Steve

  #2   Report Post  
wws
 
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wrote:

I make spinning tools for a lady who owns a sheep farm. They look like
a long slender top with a 3/32" drill rod shaft and a 1" diameter x
.100 thick brass flywheel to generate the needed inertia to keep it
spinning. These are for spinning cotton fibers.

The problem is that some of them do not stay fixed in the hole. The
hole is drilled and then reamed .0005 undersize and then the brass is
tapped onto the shaft using another piece of brass the same diameter
with a hole drilled in the center for the shaft to pass through. I
think some of the brass is being displaced by the much harder steel
shaft and it will spin on the shaft.

I have tried everything from Loctite to Super Glue to Epoxy. Loctite
was hit and miss even thought the brass and shaft were thouroughly
cleaned prior to assembly. Super Glue was the same but left an opaque
film. Epoxy was too unsightly and the customer did not like it.

I know that a shrink fit would be best but too much heat discolors the
brass. All I have to heat the brass is a toaster oven I use for
tempering. It was a max temp of around 500 degrees F. The other problem
is how to shrink the drill rod. I do not want to have to deal with dry
ice or liquid nitrogen to do this. It is too expensive to get those and
the profit margin on these is not there.

Any suggestion on how to put these together would be greatly
appreciated. The bonding agent cannot be seen on the outside of the
piece. I also tried soldering but it did not look too good.

Thanks, Steve

Can you knurl the shaft?
  #3   Report Post  
Grant Erwin
 
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Did you try reaming them .001" undersize? I know guys who would say
to braze them and then clean the brass and flux in dilute sulfuric acid.
But I think I'd first try for a heavier press fit. - GWE

wrote:

I make spinning tools for a lady who owns a sheep farm. They look like
a long slender top with a 3/32" drill rod shaft and a 1" diameter x
.100 thick brass flywheel to generate the needed inertia to keep it
spinning. These are for spinning cotton fibers.

The problem is that some of them do not stay fixed in the hole. The
hole is drilled and then reamed .0005 undersize and then the brass is
tapped onto the shaft using another piece of brass the same diameter
with a hole drilled in the center for the shaft to pass through. I
think some of the brass is being displaced by the much harder steel
shaft and it will spin on the shaft.

I have tried everything from Loctite to Super Glue to Epoxy. Loctite
was hit and miss even thought the brass and shaft were thouroughly
cleaned prior to assembly. Super Glue was the same but left an opaque
film. Epoxy was too unsightly and the customer did not like it.

I know that a shrink fit would be best but too much heat discolors the
brass. All I have to heat the brass is a toaster oven I use for
tempering. It was a max temp of around 500 degrees F. The other problem
is how to shrink the drill rod. I do not want to have to deal with dry
ice or liquid nitrogen to do this. It is too expensive to get those and
the profit margin on these is not there.

Any suggestion on how to put these together would be greatly
appreciated. The bonding agent cannot be seen on the outside of the
piece. I also tried soldering but it did not look too good.

Thanks, Steve

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carl mciver
 
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wrote in message
oups.com...
| I make spinning tools for a lady who owns a sheep farm. They look like
| a long slender top with a 3/32" drill rod shaft and a 1" diameter x
| .100 thick brass flywheel to generate the needed inertia to keep it
| spinning. These are for spinning cotton fibers.
|
| The problem is that some of them do not stay fixed in the hole. The
| hole is drilled and then reamed .0005 undersize and then the brass is
| tapped onto the shaft using another piece of brass the same diameter
| with a hole drilled in the center for the shaft to pass through. I
| think some of the brass is being displaced by the much harder steel
| shaft and it will spin on the shaft.

For the existing shafts, would the customer object if you installed a
roll pin on the shaft, flush with the flywheel? If you were to slot the
flywheel slightly narrower than the pin, you could also have a mild
interference fit, keeping it from sliding on the shaft. Swage the slot over
the pin and it's now permanent. You didn't state whether the shaft goes all
the way through the flywheel, but it would be good to use two pins if that
were the case. I had a similar problem, but on a much bigger scale, and
that was the simple only solution at the time.
For futures, why not thread the shaft into the flywheel? Throw in a
little locktite and it ought to hold great. You might have to retemper the
drill rod to tap it, though. Not sure how to work with that stuff.

  #5   Report Post  
 
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I am one of those that would say braze them. I would probably use
silver brazing. Don't know what kind of finish is needed. Would a
wire brush finish be okay?

Dan



  #6   Report Post  
Ed Huntress
 
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wrote in message
oups.com...
I am one of those that would say braze them. I would probably use
silver brazing. Don't know what kind of finish is needed. Would a
wire brush finish be okay?

Dan


I'd just put a straight knurl on the end of the shaft. If it's fully
hardened, forget it, but if it's in a normalized or annealed condition, no
problemo. It doesn't have to be pretty, just knurled enough to give it some
tooth.

--
Ed Huntress


  #7   Report Post  
Bernard R
 
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Loctite should work but you probably need to roughen the surface in the
area of the bond, an acid etch should do but a coarsish grit abrasive
should do just as well. Same with the brass, roughen the bore with some
abrasive on a rod. After abraiding chemically clean prior to bonding.

Your best bet would be to email Loctite technical dept., that's what
they're there for. Some of their products work better with with a thou
or two of clearance, but they can give you a product number tolerances
and surface preparation.

Bernard R

wrote:
I make spinning tools for a lady who owns a sheep farm. They look like
a long slender top with a 3/32" drill rod shaft and a 1" diameter x
.100 thick brass flywheel to generate the needed inertia to keep it
spinning. These are for spinning cotton fibers.

The problem is that some of them do not stay fixed in the hole. The
hole is drilled and then reamed .0005 undersize and then the brass is
tapped onto the shaft using another piece of brass the same diameter
with a hole drilled in the center for the shaft to pass through. I
think some of the brass is being displaced by the much harder steel
shaft and it will spin on the shaft.

I have tried everything from Loctite to Super Glue to Epoxy. Loctite
was hit and miss even thought the brass and shaft were thouroughly
cleaned prior to assembly. Super Glue was the same but left an opaque
film. Epoxy was too unsightly and the customer did not like it.

I know that a shrink fit would be best but too much heat discolors the
brass. All I have to heat the brass is a toaster oven I use for
tempering. It was a max temp of around 500 degrees F. The other problem
is how to shrink the drill rod. I do not want to have to deal with dry
ice or liquid nitrogen to do this. It is too expensive to get those and
the profit margin on these is not there.

Any suggestion on how to put these together would be greatly
appreciated. The bonding agent cannot be seen on the outside of the
piece. I also tried soldering but it did not look too good.

Thanks, Steve

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DeepDiver
 
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wrote in message
oups.com...

I have tried everything from Loctite to Super Glue to Epoxy.
Loctite was hit and miss even thought the brass and shaft
were thouroughly cleaned prior to assembly.


Steve, what type of Loctite did you use? There are a number of different
types of Loctite for different applications. What you want is Loctite 640
Sleeve Retainer. Here is the description from the Technical Data Sheet:

Quote:
Product 640 is designed for the bonding of cylindrical fitting
parts. The product cures when confined in the absence of air
between close fitting metal surfaces and prevents loosening
and leakage from shock and vibration. Typical applications
include filling inner voids in close fitting press fits, keyways,
and splines; mounting bearings and bushings, and making
press fits even stronger
It is imperative that the parts be absolutely clean and **grease-free**. I
recommend that you use automotive brake cleaner (or similar solvent) to
remove all traces of grease, oil, and cutting fluids.

Here are the assembly instructions for press-fit parts:

Quote:
For Press Fitted Assemblies, apply adhesive thoroughly
to both bond surfaces and assemble at high press on
rates.
Allow to cure for at least 24 hours before handling.

- Michael


  #9   Report Post  
Gerry
 
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Drill a piliot hole in the end of the steel, then insert the rod in the
bradd with Loctite, then use a sharp centerpunch to expand the shaft to
make is a tight fit in the flywheel. Done right, it will not come out

  #10   Report Post  
Randy Replogle
 
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On 13 May 2005 20:41:39 -0700, "
wrote:

I make spinning tools for a lady who owns a sheep farm. They look like
a long slender top with a 3/32" drill rod shaft and a 1" diameter x
.100 thick brass flywheel to generate the needed inertia to keep it
spinning. These are for spinning cotton fibers.

The problem is that some of them do not stay fixed in the hole. The
hole is drilled and then reamed .0005 undersize and then the brass is
tapped onto the shaft using another piece of brass the same diameter
with a hole drilled in the center for the shaft to pass through. I
think some of the brass is being displaced by the much harder steel
shaft and it will spin on the shaft.

I have tried everything from Loctite to Super Glue to Epoxy. Loctite
was hit and miss even thought the brass and shaft were thouroughly
cleaned prior to assembly. Super Glue was the same but left an opaque
film. Epoxy was too unsightly and the customer did not like it.

I know that a shrink fit would be best but too much heat discolors the
brass. All I have to heat the brass is a toaster oven I use for
tempering. It was a max temp of around 500 degrees F. The other problem
is how to shrink the drill rod. I do not want to have to deal with dry
ice or liquid nitrogen to do this. It is too expensive to get those and
the profit margin on these is not there.

Any suggestion on how to put these together would be greatly
appreciated. The bonding agent cannot be seen on the outside of the
piece. I also tried soldering but it did not look too good.

Thanks, Steve


Chamfer or slightly taper the rod so that it slides into the brass
rather than "broaching" a new diameter? Also, as was already
suggested, experiment with smaller reamed holes in the brass. You may
need to go down to .002" undersize.
Randy


  #11   Report Post  
RoyJ
 
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Press fit with .002" interference? Use a slight taper on the end to
avoid shearing off the inside of the brass. Shrink fitting is not an
option, the 3/32" shaft is way too small to get much of any size
differential.

wrote:
I make spinning tools for a lady who owns a sheep farm. They look like
a long slender top with a 3/32" drill rod shaft and a 1" diameter x
.100 thick brass flywheel to generate the needed inertia to keep it
spinning. These are for spinning cotton fibers.

The problem is that some of them do not stay fixed in the hole. The
hole is drilled and then reamed .0005 undersize and then the brass is
tapped onto the shaft using another piece of brass the same diameter
with a hole drilled in the center for the shaft to pass through. I
think some of the brass is being displaced by the much harder steel
shaft and it will spin on the shaft.

I have tried everything from Loctite to Super Glue to Epoxy. Loctite
was hit and miss even thought the brass and shaft were thouroughly
cleaned prior to assembly. Super Glue was the same but left an opaque
film. Epoxy was too unsightly and the customer did not like it.

I know that a shrink fit would be best but too much heat discolors the
brass. All I have to heat the brass is a toaster oven I use for
tempering. It was a max temp of around 500 degrees F. The other problem
is how to shrink the drill rod. I do not want to have to deal with dry
ice or liquid nitrogen to do this. It is too expensive to get those and
the profit margin on these is not there.

Any suggestion on how to put these together would be greatly
appreciated. The bonding agent cannot be seen on the outside of the
piece. I also tried soldering but it did not look too good.

Thanks, Steve

  #12   Report Post  
Joseph Gwinn
 
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Default

In article .com,
" wrote:

I make spinning tools for a lady who owns a sheep farm. They look like
a long slender top with a 3/32" drill rod shaft and a 1" diameter x
.100 thick brass flywheel to generate the needed inertia to keep it
spinning. These are for spinning cotton fibers.
[snip]

Any suggestion on how to put these together would be greatly
appreciated. The bonding agent cannot be seen on the outside of the
piece. I also tried soldering but it did not look too good.


I would think that soft soldering would work perfectly, and is easily a
factor of ten stronger than any epoxy or loctite compound, so a soldered
connection will last forever in such service. So, I would suggest
figuring out why the soldering didn't "look good". Hand feeding the
solder may be the issue. Setting things up so that only the correct
amount of solder is used can help a great deal.

The standard trick is to pre-tin the steel using tinners flux (zinc
chloride in muriatic acid), wash the vestiges of the tinners flux off
with hot water, polish the hole in the brass with a rolled-up piece of
sandpaper or sandcloth, assemble, smear with plumbers grease flux, put
a small circle of solder wire right at the junction between steel shaft
and brass wheel, set up so it does not need to be touched or manipulated
while hot, and heat the wheel (not the rod) up with a large propane
torch. (Air acetylene would be OK, but oxy-anything is too intense.
That said, faster is better, as there will be less burn and scale to
clean up.) When the solder melts and flows, remove torch and allow it
all to cool. Clean off with solvent (to get the grease flux) and steel
wool (or the equivalent scotchbrite pad) used wet.

If necessary to get the tinned steel rod to fit into the hole, wipe
excess solder off the rod while it's still hot, using a damp paper towel.

Eutectic solder (63 tin, 37 lead) melts at 371 degrees C, the lowest,
and is very shiney. The tin-lead-silver solders are also very nice
looking, strong, and easy to use. In radio work, 2% silver is very
common, and easy to get. Likewise 63-37 eutectic solder.

Joe Gwinn
  #13   Report Post  
Bob May
 
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One thing that nobody else has mentioned is to heat the brass flywheel to
maybe 400F or higher before putting it on the shaft. You will want to make
the hole only big enough to just fit on the shaft at that temp and the brass
will shrink considerably when it cools and hold hard. It will also help to
knurl the part of the shaft were the flywheel goes and this can quickly be
done with the edge of a fine file. You don't need to do a real deep knurl
to make it hold well.
When you do the pressing, a jig to hold the rod so that you can drive the
flywheel solidly to the spot where it belings will help. Even just a hole
in a block of wood if you need the flywheel in from the end an inch or so
will do fine, depending upon how accurately you need to have the flywheel in
a particular place.

--
Why isn't there an Ozone Hole at the NORTH Pole?


  #14   Report Post  
Steve W.
 
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Mill a pair of small slots 180 degrees out on the shaft in the area of
the flywheel. Install the flywheel and use a punch to peen a small area
of the brass into the slots. locking it in place.
Or vertical knurl in the same area and press the parts together with a
tighter fit (.002 undersized or so)
--
Steve Williams

wrote in message
oups.com...
I make spinning tools for a lady who owns a sheep farm. They look like
a long slender top with a 3/32" drill rod shaft and a 1" diameter x
.100 thick brass flywheel to generate the needed inertia to keep it
spinning. These are for spinning cotton fibers.

The problem is that some of them do not stay fixed in the hole. The
hole is drilled and then reamed .0005 undersize and then the brass is
tapped onto the shaft using another piece of brass the same diameter
with a hole drilled in the center for the shaft to pass through. I
think some of the brass is being displaced by the much harder steel
shaft and it will spin on the shaft.

I have tried everything from Loctite to Super Glue to Epoxy. Loctite
was hit and miss even thought the brass and shaft were thouroughly
cleaned prior to assembly. Super Glue was the same but left an opaque
film. Epoxy was too unsightly and the customer did not like it.

I know that a shrink fit would be best but too much heat discolors the
brass. All I have to heat the brass is a toaster oven I use for
tempering. It was a max temp of around 500 degrees F. The other

problem
is how to shrink the drill rod. I do not want to have to deal with dry
ice or liquid nitrogen to do this. It is too expensive to get those

and
the profit margin on these is not there.

Any suggestion on how to put these together would be greatly
appreciated. The bonding agent cannot be seen on the outside of the
piece. I also tried soldering but it did not look too good.

Thanks, Steve




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  #19   Report Post  
RoyJ
 
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On a 3/16" shaft/hole, 400 F will give you an expansion of about .0006".
Not enough to make it worth the hassle of trying to assemble it.

Bob May wrote:
One thing that nobody else has mentioned is to heat the brass flywheel to
maybe 400F or higher before putting it on the shaft. You will want to make
the hole only big enough to just fit on the shaft at that temp and the brass
will shrink considerably when it cools and hold hard. It will also help to
knurl the part of the shaft were the flywheel goes and this can quickly be
done with the edge of a fine file. You don't need to do a real deep knurl
to make it hold well.
When you do the pressing, a jig to hold the rod so that you can drive the
flywheel solidly to the spot where it belings will help. Even just a hole
in a block of wood if you need the flywheel in from the end an inch or so
will do fine, depending upon how accurately you need to have the flywheel in
a particular place.

--
Why isn't there an Ozone Hole at the NORTH Pole?


  #20   Report Post  
lionslair at consolidated dot net
 
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wrote:

I make spinning tools for a lady who owns a sheep farm. They look like
a long slender top with a 3/32" drill rod shaft and a 1" diameter x
.100 thick brass flywheel to generate the needed inertia to keep it
spinning. These are for spinning cotton fibers.

The problem is that some of them do not stay fixed in the hole. The
hole is drilled and then reamed .0005 undersize and then the brass is
tapped onto the shaft using another piece of brass the same diameter
with a hole drilled in the center for the shaft to pass through. I
think some of the brass is being displaced by the much harder steel
shaft and it will spin on the shaft.

I have tried everything from Loctite to Super Glue to Epoxy. Loctite
was hit and miss even thought the brass and shaft were thouroughly
cleaned prior to assembly. Super Glue was the same but left an opaque
film. Epoxy was too unsightly and the customer did not like it.

I know that a shrink fit would be best but too much heat discolors the
brass. All I have to heat the brass is a toaster oven I use for
tempering. It was a max temp of around 500 degrees F. The other problem
is how to shrink the drill rod. I do not want to have to deal with dry
ice or liquid nitrogen to do this. It is too expensive to get those and
the profit margin on these is not there.

Any suggestion on how to put these together would be greatly
appreciated. The bonding agent cannot be seen on the outside of the
piece. I also tried soldering but it did not look too good.

Thanks, Steve

Water, Ice and Salt. The salt drops the freezing point of water.
IIRC, Vodka helps in the melting and dropping the temp.

Martin

--
Martin Eastburn
@ home at Lion's Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

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  #21   Report Post  
Don Foreman
 
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On 13 May 2005 20:41:39 -0700, "
wrote:

I make spinning tools for a lady who owns a sheep farm. They look like
a long slender top with a 3/32" drill rod shaft and a 1" diameter x
.100 thick brass flywheel to generate the needed inertia to keep it
spinning. These are for spinning cotton fibers.

The problem is that some of them do not stay fixed in the hole. The
hole is drilled and then reamed .0005 undersize and then the brass is
tapped onto the shaft using another piece of brass the same diameter
with a hole drilled in the center for the shaft to pass through. I
think some of the brass is being displaced by the much harder steel
shaft and it will spin on the shaft.

I have tried everything from Loctite to Super Glue to Epoxy. Loctite
was hit and miss even thought the brass and shaft were thouroughly
cleaned prior to assembly. Super Glue was the same but left an opaque
film. Epoxy was too unsightly and the customer did not like it.

I know that a shrink fit would be best but too much heat discolors the
brass. All I have to heat the brass is a toaster oven I use for
tempering. It was a max temp of around 500 degrees F. The other problem
is how to shrink the drill rod. I do not want to have to deal with dry
ice or liquid nitrogen to do this. It is too expensive to get those and
the profit margin on these is not there.

Any suggestion on how to put these together would be greatly
appreciated. The bonding agent cannot be seen on the outside of the
piece. I also tried soldering but it did not look too good.

Thanks, Steve


I'm surprised that Loctite didn't do it. Which Loctite product did
you use? The threadlock stuff from the car parts store (271 and 454)
may not work well here, but I'll bet that Loctite 609 or 680 would do
the job. It works even better if you use their primer.



  #22   Report Post  
Don Foreman
 
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Default

On Sat, 14 May 2005 12:26:15 -0400, Joseph Gwinn
wrote:

In article .com,
" wrote:

I make spinning tools for a lady who owns a sheep farm. They look like
a long slender top with a 3/32" drill rod shaft and a 1" diameter x
.100 thick brass flywheel to generate the needed inertia to keep it
spinning. These are for spinning cotton fibers.
[snip]

Any suggestion on how to put these together would be greatly
appreciated. The bonding agent cannot be seen on the outside of the
piece. I also tried soldering but it did not look too good.


I would think that soft soldering would work perfectly, and is easily a
factor of ten stronger than any epoxy or loctite compound, so a soldered
connection will last forever in such service. So, I would suggest
figuring out why the soldering didn't "look good". Hand feeding the
solder may be the issue. Setting things up so that only the correct
amount of solder is used can help a great deal.

The standard trick is to pre-tin the steel using tinners flux (zinc
chloride in muriatic acid), wash the vestiges of the tinners flux off
with hot water, polish the hole in the brass with a rolled-up piece of
sandpaper or sandcloth, assemble, smear with plumbers grease flux, put
a small circle of solder wire right at the junction between steel shaft
and brass wheel, set up so it does not need to be touched or manipulated
while hot, and heat the wheel (not the rod) up with a large propane
torch. (Air acetylene would be OK, but oxy-anything is too intense.
That said, faster is better, as there will be less burn and scale to
clean up.) When the solder melts and flows, remove torch and allow it
all to cool. Clean off with solvent (to get the grease flux) and steel
wool (or the equivalent scotchbrite pad) used wet.

If necessary to get the tinned steel rod to fit into the hole, wipe
excess solder off the rod while it's still hot, using a damp paper towel.

Eutectic solder (63 tin, 37 lead) melts at 371 degrees C, the lowest,
and is very shiney. The tin-lead-silver solders are also very nice
looking, strong, and easy to use. In radio work, 2% silver is very
common, and easy to get. Likewise 63-37 eutectic solder.

Joe Gwinn


Adding to Joe's comments: I'd use a tin silver solder like Harris
Staybrite. Though a low temperature solder (430F), it's considerably
stronger than lead-tin solder and it's very fluid when it melts. No
need to pre-tin the rod, but I'd lightly countersink the flywheel on
both sides to provide a fillet area.
  #23   Report Post  
Ned Simmons
 
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In article JoeGwinn-79C5EE.21542814052005
@comcast.dca.giganews.com, says...
In article ,
Ned Simmons wrote:

In article JoeGwinn-C1340A.12261514052005
@comcast.dca.giganews.com,
says...
In article .com,
" wrote:

[snip]

I would think that soft soldering would work perfectly, and is easily a
factor of ten stronger than any epoxy or loctite compound, so a soldered
connection will last forever in such service.


A factor of 2 would be closer.


Solder metal is far stronger than epoxy or loctite, especially
silver-bearing solder. Even crappy metal is ~20,000 psi, versus ~2,000
psi for plastics.


20 ksi in shear is about right for softer grades of
aluminum. 5-10 ksi shear strength is more typical than 2
ksi for engineering plastics.

Solder does creep, but so do plastics, although epoxy
isn't bad. Solder, being soft, is less brittle.

The really strong epoxies, such as those used for repair of aluminium
airplanes, needs lots of process and care, and high-temperature cure,
and are not all that easily available. Even so, the metal is stronger.


I suspect the reason that
Loctite didn't work was that there was no clearance between
the parts. Solder's not going to work any better under
those circumstances.


This is a good point. Both require a few thousandths of an inch of
clearance to work well, although solder bridges gaps better.

But anyway, soft solder ought to work well.


As I said, soft solder is only about twice as strong in
shear as the most common Loctite retaining compounds. About
8000 psi for 63/37 in a proper joint...
http://www.matweb.com/search/SpecificMaterial.asp?
bassnum=MLSS63

And around 4000 psi for Loctite 680...
http://www.matweb.com/search/SpecificMaterial.asp?
bassnum=PLOCT127

Either one, if properly applied, should be more that strong
enough.

Ned Simmons
  #24   Report Post  
Joseph Gwinn
 
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In article ,
Ned Simmons wrote:

In article JoeGwinn-79C5EE.21542814052005
@comcast.dca.giganews.com, says...
In article ,
Ned Simmons wrote:

In article JoeGwinn-C1340A.12261514052005
@comcast.dca.giganews.com,
says...
In article .com,
" wrote:

[snip]

I would think that soft soldering would work perfectly, and is easily a
factor of ten stronger than any epoxy or loctite compound, so a
soldered connection will last forever in such service.

A factor of 2 would be closer.


Solder metal is far stronger than epoxy or loctite, especially
silver-bearing solder. Even crappy metal is ~20,000 psi, versus ~2,000
psi for plastics.


20 ksi in shear is about right for softer grades of
aluminum. 5-10 ksi shear strength is more typical than 2
ksi for engineering plastics.


We're mixing tensile and shear strengths, but I'll grant your point that
the ratio may not be 10:1 any more. Although, most of the plastics one
deals with are not quite so good as those "engineering plastics".


Solder does creep, but so do plastics, although epoxy
isn't bad. Solder, being soft, is less brittle.

The really strong epoxies, such as those used for repair of aluminium
airplanes, needs lots of process and care, and high-temperature cure,
and are not all that easily available. Even so, the metal is stronger.


I suspect the reason that
Loctite didn't work was that there was no clearance between
the parts. Solder's not going to work any better under
those circumstances.


This is a good point. Both require a few thousandths of an inch of
clearance to work well, although solder bridges gaps better.

But anyway, soft solder ought to work well.


As I said, soft solder is only about twice as strong in
shear as the most common Loctite retaining compounds. About
8000 psi for 63/37 in a proper joint...
http://www.matweb.com/search/SpecificMaterial.asp?
bassnum=MLSS63

And around 4000 psi for Loctite 680...
http://www.matweb.com/search/SpecificMaterial.asp?
bassnum=PLOCT127


I suspect one must use a primer to achieve this strength.


Either one, if properly applied, should be more than strong
enough.


That seems likely; the service doesn't seem that severe. But...

On a somewhat comic note, I recently had the task of attaching the point
of a telescoping pointer (looks like a radio antenna, used in lectures)
for a colleague. The point would unscrew in mid-lecture and fly away,
sometimes hitting someone. Sometimes me, so I "borrowed" the offending
pointer and took it home for repair.

Epoxy failed -- too much leverage between point and rod, and the bond
was almost immediately broken when the lecturer smacked the pointer
against the screen, to emphasize a point. What worked, and survived,
was 63-37 solder.

So, I don't know that I really believe that the ratio of actual bond
strength is only 2:1 in practice, despite the datasheets, although I
cannot put a number on it.

Joe Gwinn
  #25   Report Post  
Joseph Gwinn
 
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In article ,
Don Foreman wrote:

On Sat, 14 May 2005 12:26:15 -0400, Joseph Gwinn
wrote:

In article .com,
" wrote:

I make spinning tools for a lady who owns a sheep farm. They look like
a long slender top with a 3/32" drill rod shaft and a 1" diameter x
.100 thick brass flywheel to generate the needed inertia to keep it
spinning. These are for spinning cotton fibers.
[snip]

[snip]

If necessary to get the tinned steel rod to fit into the hole, wipe
excess solder off the rod while it's still hot, using a damp paper towel.

Eutectic solder (63 tin, 37 lead) melts at 371 degrees C, the lowest,
and is very shiney. The tin-lead-silver solders are also very nice
looking, strong, and easy to use. In radio work, 2% silver is very
common, and easy to get. Likewise 63-37 eutectic solder.

Joe Gwinn


Adding to Joe's comments: I'd use a tin silver solder like Harris
Staybrite. Though a low temperature solder (430F), it's considerably
stronger than lead-tin solder and it's very fluid when it melts. No
need to pre-tin the rod, but I'd lightly countersink the flywheel on
both sides to provide a fillet area.


I haven't tried silver-bearing solder on steel, but I would suspect that
the pre-tinning is still a good idea, especially as the actual soldering
step is done without touching anything.

I also note that the 63-37 solder melts at 371 degrees F (not C), so it
could be melted in a toaster oven, in a low-tech version of furnace
soldering. My main fear would be that this would heat things too
slowly, causing the flux to boil away before reaching soldering
temperature, so I'd use a small soft-flamed torch.

Joe Gwinn


  #26   Report Post  
woodworker88
 
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Ever think of keyway broaching the flywheel and milling a slot on the
shaft. Maybe use 1/16" square key, or some of the key with a large
size on half for the flywheel and smaller for the shaft. You could
then solder or epoxy the key in place, and a slot rather than keyed
shaft would also prevent the key ever falling out.

  #27   Report Post  
ATP*
 
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"DeepDiver" wrote in message
news
wrote in message
oups.com...

I have tried everything from Loctite to Super Glue to Epoxy.
Loctite was hit and miss even thought the brass and shaft
were thouroughly cleaned prior to assembly.


Steve, what type of Loctite did you use? There are a number of different
types of Loctite for different applications. What you want is Loctite 640
Sleeve Retainer. Here is the description from the Technical Data Sheet:

[quote]
Product 640 is designed for the bonding of cylindrical fitting
parts. The product cures when confined in the absence of air
between close fitting metal surfaces and prevents loosening
and leakage from shock and vibration.


Good stuff, I used that to seat a sleeve for a diesel injector in my UD
truck.


  #28   Report Post  
Don Foreman
 
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On Sun, 15 May 2005 10:50:36 -0400, Joseph Gwinn
wrote:



I haven't tried silver-bearing solder on steel, but I would suspect that
the pre-tinning is still a good idea, especially as the actual soldering
step is done without touching anything.

I also note that the 63-37 solder melts at 371 degrees F (not C), so it
could be melted in a toaster oven, in a low-tech version of furnace
soldering. My main fear would be that this would heat things too
slowly, causing the flux to boil away before reaching soldering
temperature, so I'd use a small soft-flamed torch.


The 430F tin-silver solder readily wets steel, stainless, copper and
brass. 63-37 doesn't wet steel nearly as readily, nor is it nearly as
strong.

See
http://users.goldengate.net/~dforeman/spinner/
for a quicky experiment with 3/32" drillrod in a 1" dia brass wheel.
I used a Lil' Torch, #6 tip, running oxypropane.

I countersunk the hole to provide a "collar" of solder. You can see
how the solder forms a small concave fillet on the drillrod, proof
that it is wetting it nicely. 63-37 will wet copper or brass this
way, but not steel.


  #29   Report Post  
RoyJ
 
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That's a nice job! We just did some similar sized gears (large to
small) with silphos, really ugly wick up into the smaller gear teeth.

Don Foreman wrote:
On Sun, 15 May 2005 10:50:36 -0400, Joseph Gwinn
wrote:



I haven't tried silver-bearing solder on steel, but I would suspect that
the pre-tinning is still a good idea, especially as the actual soldering
step is done without touching anything.

I also note that the 63-37 solder melts at 371 degrees F (not C), so it
could be melted in a toaster oven, in a low-tech version of furnace
soldering. My main fear would be that this would heat things too
slowly, causing the flux to boil away before reaching soldering
temperature, so I'd use a small soft-flamed torch.



The 430F tin-silver solder readily wets steel, stainless, copper and
brass. 63-37 doesn't wet steel nearly as readily, nor is it nearly as
strong.

See
http://users.goldengate.net/~dforeman/spinner/
for a quicky experiment with 3/32" drillrod in a 1" dia brass wheel.
I used a Lil' Torch, #6 tip, running oxypropane.

I countersunk the hole to provide a "collar" of solder. You can see
how the solder forms a small concave fillet on the drillrod, proof
that it is wetting it nicely. 63-37 will wet copper or brass this
way, but not steel.


  #30   Report Post  
Don Foreman
 
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On Mon, 16 May 2005 17:49:02 GMT, RoyJ wrote:

That's a nice job! We just did some similar sized gears (large to
small) with silphos, really ugly wick up into the smaller gear teeth.


I wonder if Heat Fence (American Chemical & Flux, available at welding
stores) gooped into the teeth would prevent brazing alloy from
wicking where you don't want it. I don't have any gears handy or
I'd try it.





  #33   Report Post  
Joseph Gwinn
 
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In article ,
Don Foreman wrote:

On Sun, 15 May 2005 10:50:36 -0400, Joseph Gwinn
wrote:



I haven't tried silver-bearing solder on steel, but I would suspect that
the pre-tinning is still a good idea, especially as the actual soldering
step is done without touching anything.

I also note that the 63-37 solder melts at 371 degrees F (not C), so it
could be melted in a toaster oven, in a low-tech version of furnace
soldering. My main fear would be that this would heat things too
slowly, causing the flux to boil away before reaching soldering
temperature, so I'd use a small soft-flamed torch.


The 430F tin-silver solder readily wets steel, stainless, copper and
brass. 63-37 doesn't wet steel nearly as readily, nor is it nearly as
strong.

See
http://users.goldengate.net/~dforeman/spinner/
for a quicky experiment with 3/32" drillrod in a 1" dia brass wheel.
I used a Lil' Torch, #6 tip, running oxypropane.

I countersunk the hole to provide a "collar" of solder. You can see
how the solder forms a small concave fillet on the drillrod, proof
that it is wetting it nicely. 63-37 will wet copper or brass this
way, but not steel.


Looks really nice. Maybe a bit too much solder used, but that's a
cosmetic issue only. How long did the actual soldering take?

What is the percentage composition of the tin-silver solder you used,
and the maker?

Joe Gwinn
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