Am attempting to modify my bench grinder, replacing the thermal fuse with a
thermostat, but I can't get the damn thing open. Once I remove the four
screws that fix the "end-cap" (sorry, I don't know what the "caps" on the
sides of the grinder are called...) said end-cap spins freely, but refuses
to relinquish its hold on the armature (sp?) shaft. Any ideas as to how
this thing might be built, and how to gain access to its innerds? It's a
3/4 HP BG-6, put out by AJ Tools, if that helps any. Yer basic 6" (2-wheel)
bench grinder from 30 years ago. Draws 6 Amps and spins at approx 3400 RPM.
Any help is greatly appreciated.

Thanks,

Dave

On Apr 20, 9:38*pm, "Dave" wrote:
Am attempting to modify my bench grinder, replacing the thermal fuse with a
thermostat, but I can't get the damn thing open. *Once I remove the four
screws that fix the "end-cap" (sorry, I don't know what the "caps" on the
sides of the grinder are called...) said end-cap spins freely, but refuses
to relinquish its hold on the armature (sp?) shaft. *Any ideas as to how
this thing might be built, and how to gain access to its innerds? *It's a
3/4 HP BG-6, put out by AJ Tools, if that helps any. *Yer basic 6" (2-wheel)
bench grinder from 30 years ago. *Draws 6 Amps and spins at approx 3400 RPM.
Any help is greatly appreciated.

Thanks,

Dave

A photo or two would be a big help to get started.

On Apr 21, 3:38*am, "Dave" wrote:
Am attempting to modify my bench grinder, replacing the thermal fuse with a
thermostat, but I can't get the damn thing open. *Once I remove the four
screws that fix the "end-cap" (sorry, I don't know what the "caps" on the
sides of the grinder are called...) said end-cap spins freely, but refuses
to relinquish its hold on the armature (sp?) shaft. *Any ideas as to how
this thing might be built, and how to gain access to its innerds? *It's a
3/4 HP BG-6, put out by AJ Tools, if that helps any. *Yer basic 6" (2-wheel)
bench grinder from 30 years ago. *Draws 6 Amps and spins at approx 3400 RPM.
Any help is greatly appreciated.

Thanks,

Dave

There is friction where the bearings are fitted over the motorshaft.
There is a slight possibilty there are circlips on the shaft.
The bearings are pressed into the endcaps (inside circlip common here)
and a sliding fit onto the shaft. There may be a corrosion problem on
the shaft, bit of WD40 and might help round the shaft.
You will need a tool to pry apart,do it evenly (ie all round the
joint.) An old wood chisel if you have nothing else and a hammer
perhaps.

It's important to re-assemble the caps in exactly the same position as
they came off.
Put a scratch mark across each of the two joints before dissembling.

harry wrote:

There is friction where the bearings are fitted over the motorshaft.
There is a slight possibilty there are circlips on the shaft.
The bearings are pressed into the endcaps (inside circlip common here)
and a sliding fit onto the shaft. There may be a corrosion problem on
the shaft, bit of WD40 and might help round the shaft.
You will need a tool to pry apart,do it evenly (ie all round the
joint.) An old wood chisel if you have nothing else and a hammer
perhaps.

It's important to re-assemble the caps in exactly the same position as
they came off.
Put a scratch mark across each of the two joints before dissembling.

In addition to Harry's advice, I usually find that motor shafts have
accumulated additional gunk and/or dings which make it very hard to slide
them through the bearings. To remedy this, before disassembly I will run a
fine piece of wet/dry sandpaper against the shaft as it is running. You
only need slight pressure for a small amount of time to even it out most of
the time, and you can inspect the progress by then turning it off and
inspecting the shaft by feel.

If it is shiny and feels smooth, then you can proceed to remove the bell
ends.

Jon

On Sat, 21 Apr 2012 08:41:56 -0700, "Jon Danniken"
wrote:

harry wrote:


It's important to re-assemble the caps in exactly the same position as
they came off.
Put a scratch mark across each of the two joints before dissembling.

In addition to Harry's advice, I usually find that motor shafts have
accumulated additional gunk and/or dings which make it very hard to slide
them through the bearings. To remedy this, before disassembly I will run a
fine piece of wet/dry sandpaper against the shaft as it is running. You
only need slight pressure for a small amount of time to even it out most of
the time, and you can inspect the progress by then turning it off and
inspecting the shaft by feel.

If it is shiny and feels smooth, then you can proceed to remove the bell
ends.

Jon


Plus a little lube on the shaft after doing the (above) will help too.