|
G'Day to all,
My task yesterday was to work on the cylinder for my Webster engine. I had hogged out the fins, the lower portions and drilled the inner diameter to 13mm. The last operation was to part off the work from stock when I noticed a lot of chatter. I stopped, cleaned up all the cast iron swarf and tightened the gibs. I tied again and the chatter was just as bad. I sharpened the tool which look OK and still no luck.
When I tried after tightening the carriage and compound do nothing would move I tried again and the A2Z tool post (LMS #2461) came out of the compound. The holding bolt pulled the threads out of the compound.
When examined I noticed the bolt only penetrated a 3 or 4 turns. I knew this as the threaded part was still there like a spring on the bolt.
At this time I need to either fix or replace the compound. I also plan to buy or even make a suitable replacement for the supplied bolt.
The reason for this post is to ask advice on if the compound is worth repairing and to warn others before they have problems.
Cheers,
Andrew in Melbourne
|
If I remember right from my mechanical engineering classes two full
threads of a bolt *should* be all you need. That's assuming the bolt
and nut are cut to spec out of proper materials.
Other than that, do you have room in your tool post to use a larger
diameter bolt? If not you'd have to make the hole quite a bit bigger
and put in a threaded insert.
toggle quoted message
Show quoted text
On 10/11/2011 03:14 PM, Andrew wrote: G'Day to all,
My task yesterday was to work on the cylinder for my Webster engine. I had hogged out the fins, the lower portions and drilled the inner diameter to 13mm. The last operation was to part off the work from stock when I noticed a lot of chatter. I stopped, cleaned up all the cast iron swarf and tightened the gibs. I tied again and the chatter was just as bad. I sharpened the tool which look OK and still no luck.
When I tried after tightening the carriage and compound do nothing would move I tried again and the A2Z tool post (LMS #2461) came out of the compound. The holding bolt pulled the threads out of the compound.
When examined I noticed the bolt only penetrated a 3 or 4 turns. I knew this as the threaded part was still there like a spring on the bolt.
At this time I need to either fix or replace the compound. I also plan to buy or even make a suitable replacement for the supplied bolt.
The reason for this post is to ask advice on if the compound is worth repairing and to warn others before they have problems.
Cheers,
Andrew in Melbourne
------------------------------------
Yahoo! Groups Links
--
Jerry Durand, Durand Interstellar, Inc. www.interstellar.com
tel: +1 408 356-3886, USA toll free: 1 866 356-3886
Skype: jerrydurand
|
I was thinking of seeing if a "helicoil" could work. Of course where do
I get it done?
More importantly, does the toolpost bolt have to be absolutely square to
the surface?
Cheers,
Andrew
toggle quoted message
Show quoted text
On Tue, 2011-10-11 at 15:23 -0700, Jerry Durand wrote:
If I remember right from my mechanical engineering classes two full
threads of a bolt *should* be all you need. That's assuming the bolt
and nut are cut to spec out of proper materials.
Other than that, do you have room in your tool post to use a larger
diameter bolt? If not you'd have to make the hole quite a bit bigger
and put in a threaded insert.
On 10/11/2011 03:14 PM, Andrew wrote:
G'Day to all,
My task yesterday was to work on the cylinder for my Webster engine. I had hogged out the fins, the lower portions and drilled the inner
diameter to 13mm. The last operation was to part off the work from
stock when I noticed a lot of chatter. I stopped, cleaned up all the
cast iron swarf and tightened the gibs. I tied again and the chatter
was just as bad. I sharpened the tool which look OK and still no luck.
When I tried after tightening the carriage and compound do nothing
would move I tried again and the A2Z tool post (LMS #2461) came out of
the compound. The holding bolt pulled the threads out of the compound.
When examined I noticed the bolt only penetrated a 3 or 4 turns. I
knew this as the threaded part was still there like a spring on the
bolt.
At this time I need to either fix or replace the compound. I also
plan to buy or even make a suitable replacement for the supplied bolt.
The reason for this post is to ask advice on if the compound is
worth repairing and to warn others before they have problems.
Cheers,
Andrew in Melbourne
------------------------------------
Yahoo! Groups Links
--
Jerry Durand, Durand Interstellar, Inc. www.interstellar.com
tel: +1 408 356-3886, USA toll free: 1 866 356-3886
Skype: jerrydurand
|
Generally you do the insert yourself.? Do you have a drill press or
mill?
There's various types of inserts, you might be able to get by with a
press fit one from the bottom.? Something like this (if pictures
work in this group):
On 10/11/2011 03:33 PM, Andrew wrote:
I was thinking of seeing if a "helicoil" could work. Of course where do
I get it done?
More importantly, does the toolpost bolt have to be absolutely square to
the surface?
Cheers,
Andrew
--
Jerry Durand, Durand Interstellar, Inc.
tel: +1 408 356-3886, USA toll free: 1 866 356-3886
Skype: jerrydurand
|
Hello
Andrew,
?
It
sounds like your parting tool was set too low on the work and was being pulled
in and under the work putting excessive stress on the tool post bolt. The
parting tool needs to be set dead on center. The chatter was probably from
turning?too fast. I know you didn't ask for any advice on why this happened
but thought I'd throw my two cents in.
?
Now
you ask if it is worth repairing the compound. If you can drill and tap the
compound to accept a large bolt then I'd try to repair it. I personally don't
think that a helicoil would hold up for long but that depends on how hard you
push the lathe. It's a cheap fast attempt at saving it.
?
Good
luck and please let us know how it turns out.
?
Michael
?
?
toggle quoted message
Show quoted text
?
G'Day to all,
My task yesterday was to work on the cylinder for my
Webster engine. I had hogged out the fins, the lower portions and drilled the
inner diameter to 13mm. The last operation was to part off the work from stock
when I noticed a lot of chatter. I stopped, cleaned up all the cast iron swarf
and tightened the gibs. I tied again and the chatter was just as bad. I
sharpened the tool which look OK and still no luck.
When I tried after
tightening the carriage and compound do nothing would move I tried again and
the A2Z tool post (LMS #2461) came out of the compound. The holding bolt
pulled the threads out of the compound.
When examined I noticed the
bolt only penetrated a 3 or 4 turns. I knew this as the threaded part was
still there like a spring on the bolt.
At this time I need to either
fix or replace the compound. I also plan to buy or even make a suitable
replacement for the supplied bolt.
The reason for this post is to ask
advice on if the compound is worth repairing and to warn others before they
have problems.
Cheers,
Andrew in Melbourne
|
Michael,
Thanks for the response.
The tool was set dead centre which might be part of the problem. I was
parting a 57mm diameter piece of cast iron. The overhang might have been
too much resulting in it being to low. I feel that the chatter started
as the thread was failing. I misread the situation and tightened the
usual suspects. The gibs and carriage tend to be the culprits if there
is chatter. These were tightened so that nothing would move. The only
item moving was the one axis to do the plunge cut.
I am looking for the right way of fixing IF it can be fixed at all.
Cheers,
Andrew
toggle quoted message
Show quoted text
On Tue, 2011-10-11 at 16:03 -0700, Michael Jablonski wrote:
Hello Andrew,
It sounds like your parting tool was set too low on the work and was
being pulled in and under the work putting excessive stress on the
tool post bolt. The parting tool needs to be set dead on center. The
chatter was probably from turning too fast. I know you didn't ask for
any advice on why this happened but thought I'd throw my two cents in.
Now you ask if it is worth repairing the compound. If you can drill
and tap the compound to accept a large bolt then I'd try to repair it.
I personally don't think that a helicoil would hold up for long but
that depends on how hard you push the lathe. It's a cheap fast attempt
at saving it.
Good luck and please let us know how it turns out.
Michael
-----Original Message-----
From: 7x12minilathe@...
[mailto:7x12minilathe@...] On Behalf Of Andrew
Sent: Tuesday, October 11, 2011 3:15 PM
To: 7x12minilathe@...
Subject: [7x12minilathe] Damaged compound
G'Day to all,
My task yesterday was to work on the cylinder for my Webster
engine. I had hogged out the fins, the lower portions and
drilled the inner diameter to 13mm. The last operation was to
part off the work from stock when I noticed a lot of chatter.
I stopped, cleaned up all the cast iron swarf and tightened
the gibs. I tied again and the chatter was just as bad. I
sharpened the tool which look OK and still no luck.
When I tried after tightening the carriage and compound do
nothing would move I tried again and the A2Z tool post (LMS
#2461) came out of the compound. The holding bolt pulled the
threads out of the compound.
When examined I noticed the bolt only penetrated a 3 or 4
turns. I knew this as the threaded part was still there like a
spring on the bolt.
At this time I need to either fix or replace the compound. I
also plan to buy or even make a suitable replacement for the
supplied bolt.
The reason for this post is to ask advice on if the compound
is worth repairing and to warn others before they have
problems.
Cheers,
Andrew in Melbourne
|
I do have access to a drill press and mill.
What I also need is a source of the insert in Australia. One with
wheelchair access. That failing mail-order/Internet will be the way to
go. I try and support local business's where I can.
Cheers,
Andrew
toggle quoted message
Show quoted text
On Tue, 2011-10-11 at 15:40 -0700, Jerry Durand wrote: Generally you do the insert yourself. Do you have a drill press or
mill?
There's various types of inserts, you might be able to get by with a
press fit one from the bottom. Something like this (if pictures work
in this group):
On 10/11/2011 03:33 PM, Andrew wrote:
I was thinking of seeing if a "helicoil" could work. Of course where do
I get it done?
More importantly, does the toolpost bolt have to be absolutely square to
the surface?
Cheers,
Andrew
--
Jerry Durand, Durand Interstellar, Inc. www.interstellar.com
tel: +1 408 356-3886, USA toll free: 1 866 356-3886
Skype: jerrydurand
|
Hi Andrew,
If you only pulled a few threads from the compound, there may be several more usable threads left. If so, get a longer bolt and cut it a 1/16" or so shy of bottoming out in the hole, but still tightens the post. It might be enough to get you by. In the meantime I'd order a new top slide from LMS.
Good luck with the Webster. I made one, and it runs great. I'm currently building Jerry Howell Powerhouse, which is slightly bigger, but very similar.
Frank
toggle quoted message
Show quoted text
--- In 7x12minilathe@..., "Andrew" <akayton1@...> wrote:
G'Day to all,
My task yesterday was to work on the cylinder for my Webster engine. I had hogged out the fins, the lower portions and drilled the inner diameter to 13mm. The last operation was to part off the work from stock when I noticed a lot of chatter. I stopped, cleaned up all the cast iron swarf and tightened the gibs. I tied again and the chatter was just as bad. I sharpened the tool which look OK and still no luck.
When I tried after tightening the carriage and compound do nothing would move I tried again and the A2Z tool post (LMS #2461) came out of the compound. The holding bolt pulled the threads out of the compound.
When examined I noticed the bolt only penetrated a 3 or 4 turns. I knew this as the threaded part was still there like a spring on the bolt.
At this time I need to either fix or replace the compound. I also plan to buy or even make a suitable replacement for the supplied bolt.
The reason for this post is to ask advice on if the compound is worth repairing and to warn others before they have problems.
Cheers,
Andrew in Melbourne
|
Andrew,
I went down to the shop and looked at mine. The bolt threads in almost 9 threads, so if you still have 4-5 threads left, that might do it. Also a stud and nut would take some of the guess work out of cutting a longer bolt as I suggested in my previous post.
Frank
toggle quoted message
Show quoted text
--- In 7x12minilathe@..., "Andrew" <akayton1@...> wrote:
G'Day to all,
My task yesterday was to work on the cylinder for my Webster engine. I had hogged out the fins, the lower portions and drilled the inner diameter to 13mm. The last operation was to part off the work from stock when I noticed a lot of chatter. I stopped, cleaned up all the cast iron swarf and tightened the gibs. I tied again and the chatter was just as bad. I sharpened the tool which look OK and still no luck.
When I tried after tightening the carriage and compound do nothing would move I tried again and the A2Z tool post (LMS #2461) came out of the compound. The holding bolt pulled the threads out of the compound.
When examined I noticed the bolt only penetrated a 3 or 4 turns. I knew this as the threaded part was still there like a spring on the bolt.
At this time I need to either fix or replace the compound. I also plan to buy or even make a suitable replacement for the supplied bolt.
The reason for this post is to ask advice on if the compound is worth repairing and to warn others before they have problems.
Cheers,
Andrew in Melbourne
|
Check with automotive machine shops or motorcycle repair places. Some auto parts stores sell Helicoil kits in common sizes.
Roy
toggle quoted message
Show quoted text
--- In 7x12minilathe@..., Andrew <akayton1@...> wrote:
I was thinking of seeing if a "helicoil" could work. Of course where do
I get it done?
More importantly, does the toolpost bolt have to be absolutely square to
the surface?
Cheers,
Andrew
On Tue, 2011-10-11 at 15:23 -0700, Jerry Durand wrote:
If I remember right from my mechanical engineering classes two full
threads of a bolt *should* be all you need. That's assuming the bolt
and nut are cut to spec out of proper materials.
Other than that, do you have room in your tool post to use a larger
diameter bolt? If not you'd have to make the hole quite a bit bigger
and put in a threaded insert.
On 10/11/2011 03:14 PM, Andrew wrote:
G'Day to all,
My task yesterday was to work on the cylinder for my Webster engine. I had hogged out the fins, the lower portions and drilled the inner
diameter to 13mm. The last operation was to part off the work from
stock when I noticed a lot of chatter. I stopped, cleaned up all the
cast iron swarf and tightened the gibs. I tied again and the chatter
was just as bad. I sharpened the tool which look OK and still no luck.
When I tried after tightening the carriage and compound do nothing
would move I tried again and the A2Z tool post (LMS #2461) came out of
the compound. The holding bolt pulled the threads out of the compound.
When examined I noticed the bolt only penetrated a 3 or 4 turns. I
knew this as the threaded part was still there like a spring on the
bolt.
At this time I need to either fix or replace the compound. I also
plan to buy or even make a suitable replacement for the supplied bolt.
The reason for this post is to ask advice on if the compound is
worth repairing and to warn others before they have problems.
Cheers,
Andrew in Melbourne
------------------------------------
Yahoo! Groups Links
--
Jerry Durand, Durand Interstellar, Inc. www.interstellar.com
tel: +1 408 356-3886, USA toll free: 1 866 356-3886
Skype: jerrydurand
|
i gave up on helicoils over 25 years ago. they are just the worst thing. i've since used time serts.
?
george
From: Andrew
To: 7x12minilathe@...
Sent: Tue, October 11, 2011 3:33:41 PM
Subject: Re: [7x12minilathe] Damaged compound
?
I was thinking of seeing if a "helicoil" could work. Of course where do
I get it done?
More importantly, does the toolpost bolt have to be absolutely square to
the surface?
Cheers,
Andrew
|
UPDATE:
A trip to the bolt store and 79 cents later I have a 5mm longer bolt. It
has 6 turns before it snugs down. Much better than before. The original
tool post stud makes 8 turns to hit the bottom of the same hole.
So for it looks like the simplest answer is a longer bolt and no repair
or replacement. This weekend will tell when I continue with machining
the cylinder.
Thank you to all who responded. That is what I love about this forum.
Cheers,
Andrew
toggle quoted message
Show quoted text
On Tue, 2011-10-11 at 20:59 -0700, george curtis wrote:
i gave up on helicoils over 25 years ago. they are just the worst
thing. i've since used time serts.
george
______________________________________________________________________
From: Andrew <akayton1@...>
To: 7x12minilathe@...
Sent: Tue, October 11, 2011 3:33:41 PM
Subject: Re: [7x12minilathe] Damaged compound
I was thinking of seeing if a "helicoil" could work. Of course where
do
I get it done?
More importantly, does the toolpost bolt have to be absolutely square
to
the surface?
Cheers,
Andrew
|
If I have the problem correctly, you have a hole, formerly threaded for the
stud which secures the toolpost, with the first two or three threads either
torn out, or damaged. Assuming that I have the right idea of the
situation, here is what I would do. The hole in the topslide is tapped all
the way trough the casting. I don't know this, it may not be. No matter,
take the top slide casting off the lathe. Now, there are two choices;
first, the easy one. Make sure the original threads go all the way thru the
casting. I know the hole does, but the threads are an assumption. If they
go through, fine, if they don't, find the right tap and see that they do.
File off any burrs left on the top of the casting that might have been left
when the original stud tore out. Next, get, or make, a replacement stud.
Maybe a piece of all-thread. In any case, it wants to be longer than the
original one by 6 or 8 threads, we need it to thread deeper into the
topslide casting. That's the "quick & dirty" method. Now, a more elegant
one.
Drill out only the damaged threads, no more, and make a steel plug that's a
close sliding fit in the drilled out portion of the hole, and drill it
through with the tap drill for the thread on the stud.
It wants to fit a few thou below the topslide surface when in place. Put it
in with hi-strength Loctite, let it set up a day or two, and going in from
the good threads below, tap it for the stud. More elegant still, use a tap
drill to remove the damaged threads, and thread the drilled insert before
installing it with loctite. In either case the bottom of the plug should be
turned conical to the same angle left by the drill. Otherwise, there will
be a gap, filled with swarf from tapping the plug.
The stud should stand at right angles to the top of the slide. If the
bottom of the toolpost is undamaged, whether the stud sticks up true is
moot, when things are tightened up, the toolpost will make it so.
Hope this helps.
Mert
toggle quoted message
Show quoted text
-----Original Message----- From: 7x12minilathe@... [mailto:7x12minilathe@...]On Behalf Of Andrew Sent: Tuesday, October 11, 2011 6:34 PM To: 7x12minilathe@... Subject: Re: [7x12minilathe] Damaged compound I was thinking of seeing if a "helicoil" could work. Of course where do I get it done? More importantly, does the toolpost bolt have to be absolutely square to the surface? Cheers, Andrew On Tue, 2011-10-11 at 15:23 -0700, Jerry Durand wrote:
If I remember right from my mechanical engineering classes two full
threads of a bolt *should* be all you need. That's assuming the bolt
and nut are cut to spec out of proper materials.
Other than that, do you have room in your tool post to use a larger
diameter bolt? If not you'd have to make the hole quite a bit bigger
and put in a threaded insert.
On 10/11/2011 03:14 PM, Andrew wrote:
G'Day to all,
My task yesterday was to work on the cylinder for my Webster engine. I had hogged out the fins, the lower portions and drilled the inner
diameter to 13mm. The last operation was to part off the work from
stock when I noticed a lot of chatter. I stopped, cleaned up all the
cast iron swarf and tightened the gibs. I tied again and the chatter
was just as bad. I sharpened the tool which look OK and still no luck.
When I tried after tightening the carriage and compound do nothing
would move I tried again and the A2Z tool post (LMS #2461) came out of
the compound. The holding bolt pulled the threads out of the compound.
When examined I noticed the bolt only penetrated a 3 or 4 turns. I
knew this as the threaded part was still there like a spring on the
bolt.
At this time I need to either fix or replace the compound. I also
plan to buy or even make a suitable replacement for the supplied bolt.
The reason for this post is to ask advice on if the compound is
worth repairing and to warn others before they have problems.
Cheers,
Andrew in Melbourne
------------------------------------
Yahoo! Groups Links
--
Jerry Durand, Durand Interstellar, Inc. www.interstellar.com
tel: +1 408 356-3886, USA toll free: 1 866 356-3886
Skype: jerrydurand
------------------------------------ Yahoo! Groups Links
|
First thing I did when I mounted my A2Z toolpost on mine was to make a longer stud so that I could use the stock adjuster nut/handle rather than the bolt. I guess I kind of foresaw your problem, the bolt just didn't seem like a good idea, repeatedly threading into relatively soft chinese metal. Plus the stock handle is way easier to use than having to grab a wrench every time you need to move the post. At the same time I also made a spacer for said longer stud, so I could still use the stock 4-way post without having to change the stud. I leave one of those set up with a parting tool and a grooving tool. A bit more rigid than the A2Z is for those operations, especially in steel.
Dan
toggle quoted message
Show quoted text
--- In 7x12minilathe@..., Andrew <akayton1@...> wrote:
UPDATE:
A trip to the bolt store and 79 cents later I have a 5mm longer bolt. It
has 6 turns before it snugs down. Much better than before. The original
tool post stud makes 8 turns to hit the bottom of the same hole.
So for it looks like the simplest answer is a longer bolt and no repair
or replacement. This weekend will tell when I continue with machining
the cylinder.
Thank you to all who responded. That is what I love about this forum.
Cheers,
Andrew
|
Dan,
I use the M10 bolt and Allen key for the A2Z as I find it easier to use
with my limited hand control. I also like the idea that there is one
less lever on top of the machine when it is running. Less to get in the
way or be confused when changing a tool.
Thanks for the response.
Andrew
toggle quoted message
Show quoted text
On Wed, 2011-10-12 at 16:48 +0000, oldFLH80 wrote:
First thing I did when I mounted my A2Z toolpost on mine was to make a
longer stud so that I could use the stock adjuster nut/handle rather
than the bolt. I guess I kind of foresaw your problem, the bolt just
didn't seem like a good idea, repeatedly threading into relatively
soft chinese metal. Plus the stock handle is way easier to use than
having to grab a wrench every time you need to move the post. At the
same time I also made a spacer for said longer stud, so I could still
use the stock 4-way post without having to change the stud. I leave
one of those set up with a parting tool and a grooving tool. A bit
more rigid than the A2Z is for those operations, especially in steel.
Dan
--- In 7x12minilathe@..., Andrew <akayton1@...> wrote:
UPDATE:
A trip to the bolt store and 79 cents later I have a 5mm longer
bolt. It
has 6 turns before it snugs down. Much better than before. The original
tool post stud makes 8 turns to hit the bottom of the same hole.
So for it looks like the simplest answer is a longer bolt and no repair
or replacement. This weekend will tell when I continue with machining
the cylinder.
Thank you to all who responded. That is what I love about this forum.
Cheers,
Andrew
|
Mert,
I had a look at clearing the hole, adding an insert of sorts and
re-tapping. I did not feel comfortable doing that as it might do more
harm than good.
My work around seems to be OK for now. Only time will tell if the
remaining threads will handle the stresses of machining.
I also noticed that the parting tool holder from A2Z had slipped past
its reference point. On the top there is the adjustment knob made from
brass. It has slipped past its stop point and most likely caused the
tool to be below its ideal height. My next project is to make a larger
adjustment knob.
Thanks for the comments and encouragement.
Andrew
toggle quoted message
Show quoted text
On Wed, 2011-10-12 at 07:07 -0400, MERTON B BAKER wrote:
If I have the problem correctly, you have a hole, formerly threaded
for the
stud which secures the toolpost, with the first two or three threads
either
torn out, or damaged. Assuming that I have the right idea of the
situation, here is what I would do. The hole in the topslide is tapped
all
the way trough the casting. I don't know this, it may not be. No
matter,
take the top slide casting off the lathe. Now, there are two choices;
first, the easy one. Make sure the original threads go all the way
thru the
casting. I know the hole does, but the threads are an assumption. If
they
go through, fine, if they don't, find the right tap and see that they
do.
File off any burrs left on the top of the casting that might have been
left
when the original stud tore out. Next, get, or make, a replacement
stud.
Maybe a piece of all-thread. In any case, it wants to be longer than
the
original one by 6 or 8 threads, we need it to thread deeper into the
topslide casting. That's the "quick & dirty" method. Now, a more
elegant
one.
Drill out only the damaged threads, no more, and make a steel plug
that's a
close sliding fit in the drilled out portion of the hole, and drill it
through with the tap drill for the thread on the stud.
It wants to fit a few thou below the topslide surface when in place.
Put it
in with hi-strength Loctite, let it set up a day or two, and going in
from
the good threads below, tap it for the stud. More elegant still, use a
tap
drill to remove the damaged threads, and thread the drilled insert
before
installing it with loctite. In either case the bottom of the plug
should be
turned conical to the same angle left by the drill. Otherwise, there
will
be a gap, filled with swarf from tapping the plug.
The stud should stand at right angles to the top of the slide. If the
bottom of the toolpost is undamaged, whether the stud sticks up true
is
moot, when things are tightened up, the toolpost will make it so.
Hope this helps.
Mert
-----Original Message-----
From: 7x12minilathe@...
[mailto:7x12minilathe@...]On Behalf Of Andrew
Sent: Tuesday, October 11, 2011 6:34 PM
To: 7x12minilathe@...
Subject: Re: [7x12minilathe] Damaged compound
I was thinking of seeing if a "helicoil" could work. Of course where
do
I get it done?
More importantly, does the toolpost bolt have to be absolutely square
to
the surface?
Cheers,
Andrew
On Tue, 2011-10-11 at 15:23 -0700, Jerry Durand wrote:
If I remember right from my mechanical engineering classes two full
threads of a bolt *should* be all you need. That's assuming the bolt
and nut are cut to spec out of proper materials.
Other than that, do you have room in your tool post to use a larger
diameter bolt? If not you'd have to make the hole quite a bit bigger
and put in a threaded insert.
On 10/11/2011 03:14 PM, Andrew wrote:
G'Day to all,
My task yesterday was to work on the cylinder for my Webster
engine.
I had hogged out the fins, the lower portions and drilled the inner
diameter to 13mm. The last operation was to part off the work from
stock when I noticed a lot of chatter. I stopped, cleaned up all the
cast iron swarf and tightened the gibs. I tied again and the chatter
was just as bad. I sharpened the tool which look OK and still no luck.
When I tried after tightening the carriage and compound do nothing
would move I tried again and the A2Z tool post (LMS #2461) came out
of
the compound. The holding bolt pulled the threads out of the compound.
When examined I noticed the bolt only penetrated a 3 or 4 turns. I
knew this as the threaded part was still there like a spring on the
bolt.
At this time I need to either fix or replace the compound. I also
plan to buy or even make a suitable replacement for the supplied
bolt.
The reason for this post is to ask advice on if the compound is
worth repairing and to warn others before they have problems.
Cheers,
Andrew in Melbourne
------------------------------------
Yahoo! Groups Links
--
Jerry Durand, Durand Interstellar, Inc. www.interstellar.com
tel: +1 408 356-3886, USA toll free: 1 866 356-3886
Skype: jerrydurand
------------------------------------
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In article <OOEBKAFCDAGNJFABEHBHMEBPHCAA.mertbaker@...>, MERTON B BAKER <mertbaker@...> wrote: More elegant still, use a tap
drill to remove the damaged threads, and thread the drilled insert before
installing it with loctite. Wouldn't there be difficulties in trying to get the threads to line up this way? -- Stuart
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The solution you worked out for yourself is actually the same as I suggested
for the Q&D method, and it should be satisfactory. Mert
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-----Original Message----- From: 7x12minilathe@... [mailto:7x12minilathe@...]On Behalf Of Andrew Sent: Wednesday, October 12, 2011 5:07 PM To: 7x12minilathe@... Subject: RE: [7x12minilathe] Damaged compound Mert, I had a look at clearing the hole, adding an insert of sorts and re-tapping. I did not feel comfortable doing that as it might do more harm than good. My work around seems to be OK for now. Only time will tell if the remaining threads will handle the stresses of machining. I also noticed that the parting tool holder from A2Z had slipped past its reference point. On the top there is the adjustment knob made from brass. It has slipped past its stop point and most likely caused the tool to be below its ideal height. My next project is to make a larger adjustment knob. Thanks for the comments and encouragement. Andrew On Wed, 2011-10-12 at 07:07 -0400, MERTON B BAKER wrote:
If I have the problem correctly, you have a hole, formerly threaded
for the
stud which secures the toolpost, with the first two or three threads
either
torn out, or damaged. Assuming that I have the right idea of the
situation, here is what I would do. The hole in the topslide is tapped
all
the way trough the casting. I don't know this, it may not be. No
matter,
take the top slide casting off the lathe. Now, there are two choices;
first, the easy one. Make sure the original threads go all the way
thru the
casting. I know the hole does, but the threads are an assumption. If
they
go through, fine, if they don't, find the right tap and see that they
do.
File off any burrs left on the top of the casting that might have been
left
when the original stud tore out. Next, get, or make, a replacement
stud.
Maybe a piece of all-thread. In any case, it wants to be longer than
the
original one by 6 or 8 threads, we need it to thread deeper into the
topslide casting. That's the "quick & dirty" method. Now, a more
elegant
one.
Drill out only the damaged threads, no more, and make a steel plug
that's a
close sliding fit in the drilled out portion of the hole, and drill it
through with the tap drill for the thread on the stud.
It wants to fit a few thou below the topslide surface when in place.
Put it
in with hi-strength Loctite, let it set up a day or two, and going in
from
the good threads below, tap it for the stud. More elegant still, use a
tap
drill to remove the damaged threads, and thread the drilled insert
before
installing it with loctite. In either case the bottom of the plug
should be
turned conical to the same angle left by the drill. Otherwise, there
will
be a gap, filled with swarf from tapping the plug.
The stud should stand at right angles to the top of the slide. If the
bottom of the toolpost is undamaged, whether the stud sticks up true
is
moot, when things are tightened up, the toolpost will make it so.
Hope this helps.
Mert
-----Original Message-----
From: 7x12minilathe@...
[mailto:7x12minilathe@...]On Behalf Of Andrew
Sent: Tuesday, October 11, 2011 6:34 PM
To: 7x12minilathe@...
Subject: Re: [7x12minilathe] Damaged compound
I was thinking of seeing if a "helicoil" could work. Of course where
do
I get it done?
More importantly, does the toolpost bolt have to be absolutely square
to
the surface?
Cheers,
Andrew
On Tue, 2011-10-11 at 15:23 -0700, Jerry Durand wrote:
If I remember right from my mechanical engineering classes two full
threads of a bolt *should* be all you need. That's assuming the bolt
and nut are cut to spec out of proper materials.
Other than that, do you have room in your tool post to use a larger
diameter bolt? If not you'd have to make the hole quite a bit bigger
and put in a threaded insert.
On 10/11/2011 03:14 PM, Andrew wrote:
G'Day to all,
My task yesterday was to work on the cylinder for my Webster
engine.
I had hogged out the fins, the lower portions and drilled the inner
diameter to 13mm. The last operation was to part off the work from
stock when I noticed a lot of chatter. I stopped, cleaned up all the
cast iron swarf and tightened the gibs. I tied again and the chatter
was just as bad. I sharpened the tool which look OK and still no luck.
When I tried after tightening the carriage and compound do nothing
would move I tried again and the A2Z tool post (LMS #2461) came out
of
the compound. The holding bolt pulled the threads out of the compound.
When examined I noticed the bolt only penetrated a 3 or 4 turns. I
knew this as the threaded part was still there like a spring on the
bolt.
At this time I need to either fix or replace the compound. I also
plan to buy or even make a suitable replacement for the supplied
bolt.
The reason for this post is to ask advice on if the compound is
worth repairing and to warn others before they have problems.
Cheers,
Andrew in Melbourne
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Jerry Durand, Durand Interstellar, Inc. www.interstellar.com
tel: +1 408 356-3886, USA toll free: 1 866 356-3886
Skype: jerrydurand
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Nope. The plug is pre drilled with the tap drill, and locked in place. The
tap is then run in from below, where the pre-existing threads are undamaged,
and thus will segue into the insert with no problem, especially if it has
been fitted correctly at the lower end. You would indeed have a problem if
you tried to start the tap from the top surface.
Mert
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-----Original Message----- From: 7x12minilathe@... [mailto:7x12minilathe@...]On Behalf Of lists Sent: Wednesday, October 12, 2011 5:16 PM To: 7x12minilathe@... Subject: Re: [7x12minilathe] Damaged compound In article <OOEBKAFCDAGNJFABEHBHMEBPHCAA.mertbaker@...>, MERTON B BAKER <mertbaker@...> wrote: More elegant still, use a tap
drill to remove the damaged threads, and thread the drilled insert before
installing it with loctite. Wouldn't there be difficulties in trying to get the threads to line up this way? -- Stuart ------------------------------------ Yahoo! Groups Links
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There's a Loctite product that may help restore the original threads. I've had some success with it and some failures - you'll have to decide if it's worth the bother.
Roy
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--- In 7x12minilathe@..., Andrew <akayton1@...> wrote:
UPDATE:
A trip to the bolt store and 79 cents later I have a 5mm longer bolt. It
has 6 turns before it snugs down. Much better than before. The original
tool post stud makes 8 turns to hit the bottom of the same hole.
So for it looks like the simplest answer is a longer bolt and no repair
or replacement. This weekend will tell when I continue with machining
the cylinder.
Thank you to all who responded. That is what I love about this forum.
Cheers,
Andrew
On Tue, 2011-10-11 at 20:59 -0700, george curtis wrote:
i gave up on helicoils over 25 years ago. they are just the worst
thing. i've since used time serts.
george
______________________________________________________________________
From: Andrew <akayton1@...>
To: 7x12minilathe@...
Sent: Tue, October 11, 2011 3:33:41 PM
Subject: Re: [7x12minilathe] Damaged compound
I was thinking of seeing if a "helicoil" could work. Of course where
do
I get it done?
More importantly, does the toolpost bolt have to be absolutely square
to
the surface?
Cheers,
Andrew
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