Taper-Lock vs tapered shaft

[bob prohaska]

I've long wondered how well a "taper-lock" pulley secures
to a shaft, relative to a traditional tapered shaft and bore.

The idea would be to use a taper-lock flange on a straight
shaft engine to drive a flange-driven load like a single
bearing generator. No immediate project in hand, just curious.

Thanks for reading,

bob prohaska

[Jim Wilkins]

"bob prohaska" wrote in message news:ud5877$1j4rg$1...@dont-email.me...

---------------------

My sawmill has a 6.5HP gas engine connected to a 3/4" extension shaft
through a Lovejoy coupler, and a taper-lock hub pulley on the far end of the
shaft. When the engine lugged starting the saw, because the new belt and
pulley wouldn't slip, the black rubber spider in the coupler was torn up. I
had used the L095 that had worked fine on the previous 5.5HP engine borrowed
from the splitter. I looked up the data and found that I should have
upgraded to an L100 to handle the engine's peak torque which for a 4-stroke
is several times the average, as calculated from the horsepower and speed.

The 3/4" extension, same as the engine's, and 1" shaft in the speed reducer
were calculated for a rotational torque of 1/2 the UTS of mild steel, with a
margin, at 10HP.

Other than that it has held up well. The hardest part was aligning the
engine and extension shaft to within Lovejoy's angular and offset specs. The
mount for both is a weldment that shifted from shrinkage.

Price the taper lock pulleys and hubs. They, the pillow blocks and shafts
cost as much as the engine.

I personally wouldn't rely on the engine shaft to drive a rigidly attached
load unless it was located by precision surfaces on the engine block.

[bob prohaska]

Jim Wilkins <murat...@gmail.com> wrote:
>
> I personally wouldn't rely on the engine shaft to drive a rigidly attached
> load unless it was located by precision surfaces on the engine block.
>

Understood. Some sort of centering bosses on the engine and load are
mandatory, with matching features on the adapter, whatever that turns
out to be.

I'm mostly wondering about how well taper-lock style couplings resist
vibration over time. A traditional tapered shaft in a tapered flywheel
or coupling flange is more-or-less an eternal union provided it's
assembled correctly. Is a properly-assembled taper lock comparably
permanent? The static torque rating on a 19 mm (~3/4") shaft appears
to be around 40 ft-lbs, which is adequate for a 5 hp engine provided
it stays tight under engine vibration.

Thanks for writing,

bob prohaska

[Jim Wilkins]

"bob prohaska" wrote in message news:ud61en$1qflq$1...@dont-email.me...

I'm mostly wondering about how well taper-lock style couplings resist
vibration over time. A traditional tapered shaft in a tapered flywheel
or coupling flange is more-or-less an eternal union provided it's
assembled correctly. Is a properly-assembled taper lock comparably
permanent? The static torque rating on a 19 mm (~3/4") shaft appears
to be around 40 ft-lbs, which is adequate for a 5 hp engine provided
it stays tight under engine vibration.

Thanks for writing,

bob prohaska

----------------------------
https://www.farrellbearings.co.nz/site/farrellbearings/files/man%20cat/Taper%20Lock%20Bush%20Installation%20Guide.pdf
"Slip will tend to occur at the bush/shaft interface, at the prescribed
torque, unless a key is fitted. With a key, the slip tendency transfers to
the bush/hub interface at a greater torque value related to the ratio of
bush outer dia. to bore dia."

https://dpk3n3gg92jwt.cloudfront.net/domains/bbman2/bushinginstallation.pdf

You might try downloading the Audel Millwrights and Mechanics Guide. I have
a hard copy and need to limit my monthly cellular data use so I didn't try
any of the links.

[Bob La Londe]

A common pulley which might help with your question is a two piece
pulley that joins a hub with a ring by a taper. All I have seen use
bolts to pull the two tapers together. Some also use a split or semi
split hub to clamp onto the shaft, but others use a key.

The first noticed point of failure I have seen a couple times is that
the bolts holding the two piece together break off. Whether they broke,
from being over torqued, from vibrations, or because the pulled do
something I do not know.

I suspect for most tapered motor shafts a tapered pulley is pulled onto
the shaft with a bolt in the end of the shaft.

A washer between the bolt and the pulley/shaft could be another pulley I
suppose, but centering could be an issue.

You know... I don't know if any of that is useful, but I'm going to hit
send anyway.


--
Bob La Londe
CNC Molds N Stuff


--
This email has been checked for viruses by AVG antivirus software.
www.avg.com

[Jim Wilkins]

"Bob La Londe" wrote in message news:ud81nj$23v17$1...@dont-email.me...

The first noticed point of failure I have seen a couple times is that
the bolts holding the two piece together break off. Whether they broke,
from being over torqued, from vibrations, or because the pulled do
something I do not know.

-----------------------

That fits with farrelbearings' statement that the tapered bushing may slip
in the pulley hub if a key prevents it from slipping on the shaft.

[bob prohaska]

Jim Wilkins <murat...@gmail.com> wrote:
> ----------------------------
> https://www.farrellbearings.co.nz/site/farrellbearings/files/man%20cat/Taper%20Lock%20Bush%20Installation%20Guide.pdf
> "Slip will tend to occur at the bush/shaft interface, at the prescribed
> torque, unless a key is fitted. With a key, the slip tendency transfers to
> the bush/hub interface at a greater torque value related to the ratio of
> bush outer dia. to bore dia."
>
> https://dpk3n3gg92jwt.cloudfront.net/domains/bbman2/bushinginstallation.pdf

The link above is most informative. I was surprised to see a strict
prohibition on lubricating the taper in any way, with a warning that
it might cause splitting of the bushing or bore. That would seem to
fairly large clamping force on the shaft.

>
> You might try downloading the Audel Millwrights and Mechanics Guide. I have
> a hard copy and need to limit my monthly cellular data use so I didn't try
> any of the links.

Couldn't find any no-cost downloads, a physical copy is 60-80$, so I'll
wait till it's actually needed.

Thanks very much for writing!

bob prohaska

[Jim Wilkins]

"bob prohaska" wrote in message news:ud8dr4$25prs$1...@dont-email.me...

> You might try downloading the Audel Millwrights and Mechanics Guide. I
> have
> a hard copy and need to limit my monthly cellular data use so I didn't try
> any of the links.

Couldn't find any no-cost downloads, a physical copy is 60-80$, so I'll
wait till it's actually needed.

Thanks very much for writing!

bob prohaska

--------------------------

Among other ways the book shows identical hubs on the driving and driven
shaft, the same diameter and faced flat and square, like the two sections of
an edge finder. The Lovejoy coupler mounted backwards worked for me. You
adjust until they meet exactly.
https://www.kleen-ritecorp.com/p-8629-lovejoy-l095-1-1-8-24mm-flex-coupling-1-1-8in-x-24mm.aspx

[Leon Fisk]

On Tue, 5 Sep 2023 23:32:52 -0000 (UTC)
bob prohaska <b...@www.zefox.net> wrote:

<snip>

>Couldn't find any no-cost downloads, a physical copy is 60-80$, so I'll
>wait till it's actually needed.

Maybe🤷

https://annas-archive.org/search?q=Audel+Millwrights

--
Leon Fisk
Grand Rapids MI

[Jim Wilkins]

"Leon Fisk" wrote in message news:ud9rfp$2gasq$1...@dont-email.me...

https://annas-archive.org/search?q=Audel+Millwrights

Leon Fisk

--------------------------

Thanks, that is quite a collection.

[bob prohaska]

+1

bob prohaska