Mill parts

[Snag]

I'm in need of help finding a part for my bench top mill , RF45 clone
. It's the same as the Grizzly G0484 and they show the part as
discontinued . I'm looking for a replacement X axis lead screw nut . The
Grizzly part number is P0484032 , maybe someone is making a replacement
since there must be 10's of thousands of these machines around . The
thread is Acme 15/16 (24 mm) diameter with an eight TPI thread . I've
seen articles about people making replacements using plastic - maybe
ABS? - and heat/pressure forming the threads but I'd lots rather find a
direct drop-in replacement .

[Joe Gwinn]

Post by Snag
I'm in need of help finding a part for my bench top mill , RF45 clone
. It's the same as the Grizzly G0484 and they show the part as
discontinued . I'm looking for a replacement X axis lead screw nut . The
Grizzly part number is P0484032 , maybe someone is making a replacement
since there must be 10's of thousands of these machines around . The
thread is Acme 15/16 (24 mm) diameter with an eight TPI thread . I've
seen articles about people making replacements using plastic - maybe
ABS? - and heat/pressure forming the threads but I'd lots rather find a
direct drop-in replacement .

ABS would not work as it doesn't make a very good bearing surface.

Delrin works well for thermally forming a nut on an existing metal
leadscrew. There are many you-tube videos.

Joe

[Jim Wilkins]

"Joe Gwinn" wrote in message news:***@4ax.com...

Delrin works well for thermally forming a nut on an existing metal
leadscrew. There are many you-tube videos.

Joe
-------------------------------
Generic acetal cold-formed to sharp points when I knurled it.

[Joe Gwinn]

On Tue, 19 Nov 2024 22:38:16 -0500, "Jim Wilkins"

Post by Joe Gwinn
Delrin works well for thermally forming a nut on an existing metal
leadscrew. There are many you-tube videos.
Joe
-------------------------------
Generic acetal cold-formed to sharp points when I knurled it.

Yes. So do it warm.

By thermal forming I mean melting.

Here is a related posting, but one would not want to take the real
leadscrew and make it into a big self-tapping screw. I haven't found
the videos on doing this on the actual leadscrew without damaging or
risking it.

.<https://www.instructables.com/DIY-Anti-Backlash-Nuts-Super-Cheap-and-Simple/>

And as others have said, no glue will stick to delrin, so the
attachment must be mechanical.

Joe

[Jim Wilkins]

"Joe Gwinn" wrote in message news:***@4ax.com...

On Tue, 19 Nov 2024 22:38:16 -0500, "Jim Wilkins"

Post by Joe Gwinn
Delrin works well for thermally forming a nut on an existing metal
leadscrew. There are many you-tube videos.
Joe
-------------------------------
Generic acetal cold-formed to sharp points when I knurled it.

Yes. So do it warm.

By thermal forming I mean melting.

Here is a related posting, but one would not want to take the real
leadscrew and make it into a big self-tapping screw. I haven't found
the videos on doing this on the actual leadscrew without damaging or
risking it.

.<https://www.instructables.com/DIY-Anti-Backlash-Nuts-Super-Cheap-and-Simple/>

And as others have said, no glue will stick to delrin, so the
attachment must be mechanical.

Joe
--------------------------------------------
I would try making a mild steel tap that closely resembled the leadscrew to
pre-form the Delrin before compressing it onto the heated original. Possibly
if the nut blank was tapped slightly tight and both heated the original
could be screwed into it. Annealing might relax the plastic to a sliding
fit. The tap could give ID and OD clearance so only the thread flanks are
snug. The lathe will ensure the correct pitch and the tap's thread form
doesn't have to be perfect.

[Jim Wilkins]

"Jim Wilkins" wrote in message news:vhl9rg$7h7l$***@dont-email.me...

I would try making a mild steel tap that closely resembled the leadscrew to
pre-form the Delrin before compressing it onto the heated original.
-----------------------------
I just discovered that the metric equivalent to Acme has a 30 instead of 29
degree thread groove angle.

[Leon Fisk]

On Tue, 19 Nov 2024 17:27:05 -0600

Post by Snag
I'm in need of help finding a part for my bench top mill , RF45 clone
. It's the same as the Grizzly G0484 and they show the part as
discontinued . I'm looking for a replacement X axis lead screw nut . The
Grizzly part number is P0484032 , maybe someone is making a replacement
since there must be 10's of thousands of these machines around . The
thread is Acme 15/16 (24 mm) diameter with an eight TPI thread . I've
seen articles about people making replacements using plastic - maybe
ABS? - and heat/pressure forming the threads but I'd lots rather find a
direct drop-in replacement .

Maybe Jet has something. Their JT9 and JMD45 mills look similar:

https://jettools.com/jmd-45gh-geared-head-square-column-mill-drill

Manual link to pdf on that page has a parts section.

This might be the part you're looking for but you won't like the price😬

https://jettools.com/table-nut-jmd18-223a

[Snag]

Post by Leon Fisk
On Tue, 19 Nov 2024 17:27:05 -0600

Post by Snag
I'm in need of help finding a part for my bench top mill , RF45 clone
. It's the same as the Grizzly G0484 and they show the part as
discontinued . I'm looking for a replacement X axis lead screw nut . The
Grizzly part number is P0484032 , maybe someone is making a replacement
since there must be 10's of thousands of these machines around . The
thread is Acme 15/16 (24 mm) diameter with an eight TPI thread . I've
seen articles about people making replacements using plastic - maybe
ABS? - and heat/pressure forming the threads but I'd lots rather find a
direct drop-in replacement .

https://jettools.com/jmd-45gh-geared-head-square-column-mill-drill
Manual link to pdf on that page has a parts section.
This might be the part you're looking for but you won't like the price😬
https://jettools.com/table-nut-jmd18-223a

Yup , that's what it looks like . But I don't know what pitch the
threads are ... They don't all use 8 TPI , some use 10 .
I saw a comment about making a brass/bronze nut to thread into the
original , I may end up going that way . I've got just over .020 lash ,
which isn't a problem with most projects , but my current project of
making tool holders for my QCTP is having problems .

[Leon Fisk]

On Wed, 20 Nov 2024 09:25:37 -0600
Snag <***@msn.com> wrote:

<snip>

Post by Snag
Yup , that's what it looks like . But I don't know what pitch the
threads are ... They don't all use 8 TPI , some use 10 .

Guessing by the part Description Size "TM23.7-10" it's likely to be
10 TPI. Of course that 10 could be meant as Metric I suppose. No
clue as to how Metric is specified in relation to our TPI meaning...

Just an off the wall thought... could you use Babbit and a home brew
mold to catch the pour for a shape you could use?

[Snag]

Post by Leon Fisk
On Wed, 20 Nov 2024 09:25:37 -0600
<snip>

Post by Snag
Yup , that's what it looks like . But I don't know what pitch the
threads are ... They don't all use 8 TPI , some use 10 .

Guessing by the part Description Size "TM23.7-10" it's likely to be
10 TPI. Of course that 10 could be meant as Metric I suppose. No
clue as to how Metric is specified in relation to our TPI meaning...
Just an off the wall thought... could you use Babbit and a home brew
mold to catch the pour for a shape you could use?

I could cast it with bronze/brass ... I'd have to make a pattern and
a core ... I have the material and the flasks and green sand . Actually
it would be easier to make a lost foam pattern to cast it .

[Bob La Londe]

  I'm in need of help finding a part for my bench top mill , RF45
clone . It's the same as the Grizzly G0484 and they show the part as
discontinued . I'm looking for a replacement X axis lead screw nut . The
Grizzly part number is P0484032 , maybe someone is making a replacement
since there must be 10's of thousands of these machines around . The
thread is Acme 15/16 (24 mm) diameter with an eight TPI thread . I've
seen articles about people making replacements using plastic - maybe
ABS? - and heat/pressure forming the threads but I'd lots rather find a
direct drop-in replacement .

Would have responded sooner, but I do not have a proper Usenet client
installed on the house computer.

My first response would also be to sleeve the existing nut. This
addresses your request. I would suggest very tight sliding fit and use
sleeve and bearing locker.

The search for a new one is what it is. A search. I have no special
insights other than as you clearly already know that these machines may
be sold under different labels. I suggest may be ask Matt at Precision
Mathews. Admittedly he may be more responsive on parts to a customer
than somebody who just wants parts, but he is very good at supporting
customers.

Now for the tangents.

Backlash should not be a huge issue if your gibbs are adjusted, you use
your gibb locks, and you mostly conventional mill. Accuracy probably is
not a huge issue, but if it is take all measured moves using the hand
wheel dials in only one direction. If you really need to be able find a
postion accurately in two directions there are two solutions. The nice
one is a DRO with glass scales. The alternative is some dial indicators
mounted to the table. I have a dial indicator mounted semi permanently
on one of my lathes.

As was already mentioned ABS is a terrible idea for all the reasons
stated. Acetal (Delrin is a trade name) is used for bearings, axis
nuts, and a variety of other things. Its pretty tough and there are
commercial products made form the stuff. HOWEVER. Acetal does not
accept any common adhesive well at all. It would not be a good option
for boring and sleeving the old nut. Bronze or even brass would be
better. I do not know if adhesives would stick to oilite bronze. Maybe
another rabbit hole to research there.

I looked. I do not have an acme tap that big. You will have to cut it
on your lathe (or buy a very expensive tap) after grinding a suitable
inside cutting tool. It will probably chatter pretty bad, so it might
be time to consider making a solid tool post that bolts directly to the
cross slide.

[Snag]

Post by Bob La Londe

   I'm in need of help finding a part for my bench top mill , RF45
clone . It's the same as the Grizzly G0484 and they show the part as
discontinued . I'm looking for a replacement X axis lead screw nut .
The Grizzly part number is P0484032 , maybe someone is making a
replacement since there must be 10's of thousands of these machines
around . The thread is Acme 15/16 (24 mm) diameter with an eight TPI
thread . I've seen articles about people making replacements using
plastic - maybe ABS? - and heat/pressure forming the threads but I'd
lots rather find a direct drop-in replacement .

Would have responded sooner, but I do not have a proper Usenet client
installed on the house computer.
My first response would also be to sleeve the existing nut.  This
addresses your request.  I would suggest very tight sliding fit and use
sleeve and bearing locker.
The search for a new one is what it is.  A search.  I have no special
insights other than as you clearly already know that these machines may
be sold under different labels.  I suggest may be ask Matt at Precision
Mathews.  Admittedly he may be more responsive on parts to a customer
than somebody who just wants parts, but he is very good at supporting
customers.
Now for the tangents.
Backlash should not be a huge issue if your gibbs are adjusted, you use
your gibb locks, and you mostly conventional mill.  Accuracy probably is
not a huge issue, but if it is take all measured moves using the hand
wheel dials in only one direction.  If you really need to be able find a
postion accurately in two directions there are two solutions.  The nice
one is a DRO with glass scales.  The alternative is some dial indicators
mounted to the table.  I have a dial indicator mounted semi permanently
on one of my lathes.

I just a few months ago ditched the Shumatech DRO and capacitive
scales for a nice glass scale DRO that reads to tenths ... and I have a
dial indicator on a mount that clamps to the front v way on the lathe in
addition to one on a magnetic mount . Also have a couple of Starrett
back plunger indicators with hardware and one NIB indicator for a backup
in case I break one .

Post by Bob La Londe
As was already mentioned ABS is a terrible idea for all the reasons
stated.  Acetal (Delrin is a trade name) is used for bearings, axis
nuts, and a variety of other things.  Its pretty tough and there are
commercial products made form the stuff.  HOWEVER.  Acetal does not
accept any common adhesive well at all.  It would not be a good option
for boring and sleeving the old nut.  Bronze or even brass would be
better.  I do not know if adhesives would stick to oilite bronze.  Maybe
another rabbit hole to research there.

If I sleeve the original it'll be with bearing bronze or some Ampco
45 aluminum bronze . I have both on hand ...

Post by Bob La Londe
I looked.  I do not have an acme tap that big.  You will have to cut it
on your lathe (or buy a very expensive tap) after grinding a suitable
inside cutting tool.  It will probably chatter pretty bad, so it might
be time to consider making a solid tool post that bolts directly to the
cross slide.

I already made a post type boring bar holder that bolts directly to
the compound . I can use the lathe leadscrew as a pattern to grind the
tool since it too is 8 TPI . Actually I have another leadscrew that's in
very good condition that I would use .