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My lathe had pretty poor mesh between the handwheel gear and the rack.
To address the problem I slid the rack about 1/2 inch to one side and moved the
rack down. Everything worked out pretty well. However, one hole is a bit too
high. I am thinking of a couple of ways to fix the problem.
1. Start over and drill/tap all of the holes again. Hoping not to do this, as its not
? ? clear I will succeed the second time.
2. Elongate the through hole in the rack so that the screw will go in without distorting the
? ? rack. The hole is off by about .030" and I believe there is probably enough metal
? ? above the hole in the rack to fit. I am not sure what the rack is made of. It seems like
? ? steel which I don't think is hardened. But I don't really like the idea of changing the?
? ? rack this way.
3. Fill the hole with JB Weld or some other sort of epoxy-like filler and then re-drill and?
? ? tap. I assume this wouldn't be as strong as drilling the holes in new locations (i.e., #1 above)
? ? but I don't think this will be a concern. I haven't tried moving holes this way before so I am
? ? not sure it will be easy to move the holes a small amount like this.
I would like to get some advice on what is the best way to correct this. Thanks.
Tom
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On Thu, 13 Jan 2022, thomasfkeefe@... wrote: My lathe had pretty poor mesh between the handwheel gear and the rack.
To address the problem I slid the rack about 1/2 inch to one side and moved the
rack down. Everything worked out pretty well. However, one hole is a bit too
high. I am thinking of a couple of ways to fix the problem.
1. Start over and drill/tap all of the holes again. Hoping not to do this, as its not
clear I will succeed the second time.
2. Elongate the through hole in the rack so that the screw will go in without distorting the
rack. The hole is off by about .030" and I believe there is probably enough metal
above the hole in the rack to fit. I am not sure what the rack is made of. It seems like
steel which I don't think is hardened. But I don't really like the idea of changing the
rack this way.
3. Fill the hole with JB Weld or some other sort of epoxy-like filler and then re-drill and
tap. I assume this wouldn't be as strong as drilling the holes in new locations (i.e., #1 above)
but I don't think this will be a concern. I haven't tried moving holes this way before so I am
not sure it will be easy to move the holes a small amount like this.
I would like to get some advice on what is the best way to correct this. Thanks.
Tom _._,_._,_
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Hi Tom,
I have tried your suggestion 3 and the problem is that the drill cuts the epoxy much faster than the steel and this forces the drill bit to follow the original hole. The best way I have found is to fill the holes with some steel screw threaded bar leaving a little protruding. Put some epoxy on the screw thread when fitting the screw. Allow the epoxy to set and then file the steel flush with the surface. Centre punch the new hole position and re drill the hole.
Mike
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The way I?handle problems like this is to drill the hole significantly larger and tap it. Then insert a bolt that fits the tap, using JB Weld as your thread-locking compound.? Once that sets, saw off the bolt level with the surface.??
Now, your original hole is gone and you have new metal at the location, so you can drill and tap it in the proper place with no worries.? (If it would be difficult to saw off the bolt level with the surface, you can instead saw the top of the bolt off ahead of time and manipulate the cut place it to be level with the surface before the JB Weld sets).
Mike Taglieri
My lathe had pretty poor mesh between the handwheel gear and the rack.
To address the problem I slid the rack about 1/2 inch to one side and moved the
rack down. Everything worked out pretty well. However, one hole is a bit too
high. I am thinking of a couple of ways to fix the problem.
1. Start over and drill/tap all of the holes again. Hoping not to do this, as its not
? ? clear I will succeed the second time.
2. Elongate the through hole in the rack so that the screw will go in without distorting the
? ? rack. The hole is off by about .030" and I believe there is probably enough metal
? ? above the hole in the rack to fit. I am not sure what the rack is made of. It seems like
? ? steel which I don't think is hardened. But I don't really like the idea of changing the?
? ? rack this way.
3. Fill the hole with JB Weld or some other sort of epoxy-like filler and then re-drill and?
? ? tap. I assume this wouldn't be as strong as drilling the holes in new locations (i.e., #1 above)
? ? but I don't think this will be a concern. I haven't tried moving holes this way before so I am
? ? not sure it will be easy to move the holes a small amount like this.
I would like to get some advice on what is the best way to correct this. Thanks.
Tom
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Try modifying the bolt for that one hole with a step/recess in a portion of the thread and turn the head undersize. I assume it is a SHCS.
On Friday, January 14, 2022, 03:30:38 AM PST, Miket_NYC <mctaglieri@...> wrote:
The way I?handle problems like this is to drill the hole significantly larger and tap it. Then insert a bolt that fits the tap, using JB Weld as your thread-locking compound.? Once that sets, saw off the bolt level with the surface.??
Now, your original hole is gone and you have new metal at the location, so you can drill and tap it in the proper place with no worries.? (If it would be difficult to saw off the bolt level with the surface, you can instead saw the top of the bolt off ahead of time and manipulate the cut place it to be level with the surface before the JB Weld sets).
Mike Taglieri
My lathe had pretty poor mesh between the handwheel gear and the rack.
To address the problem I slid the rack about 1/2 inch to one side and moved the
rack down. Everything worked out pretty well. However, one hole is a bit too
high. I am thinking of a couple of ways to fix the problem.
1. Start over and drill/tap all of the holes again. Hoping not to do this, as its not
? ? clear I will succeed the second time.
2. Elongate the through hole in the rack so that the screw will go in without distorting the
? ? rack. The hole is off by about .030" and I believe there is probably enough metal
? ? above the hole in the rack to fit. I am not sure what the rack is made of. It seems like
? ? steel which I don't think is hardened. But I don't really like the idea of changing the?
? ? rack this way.
3. Fill the hole with JB Weld or some other sort of epoxy-like filler and then re-drill and?
? ? tap. I assume this wouldn't be as strong as drilling the holes in new locations (i.e., #1 above)
? ? but I don't think this will be a concern. I haven't tried moving holes this way before so I am
? ? not sure it will be easy to move the holes a small amount like this.
I would like to get some advice on what is the best way to correct this. Thanks.
Tom
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1.? ?Find and turn a piece of cast iron to fit the existing thread in the lathe bed. Epoxy or loctite in place and drill and tap a new hole aligned with the rack. DO NOT try this by filling the thread with epoxy or steel, either one is too different from the cast iron to give a well aligned result. 2.? ?Fill and hammer the hole in the rack shut with a similar material. Drill new hole to line up with thread in bed casting. 3.? ?Leave both holes as they are and drill and tap a new hole 10 mm to one side, into rack and bed. Tap as needed and screw snug.
My lathe had pretty poor mesh between the handwheel gear and the rack.
To address the problem I slid the rack about 1/2 inch to one side and moved the
rack down. Everything worked out pretty well. However, one hole is a bit too
high. I am thinking of a couple of ways to fix the problem.
1. Start over and drill/tap all of the holes again. Hoping not to do this, as its not
? ? clear I will succeed the second time.
2. Elongate the through hole in the rack so that the screw will go in without distorting the
? ? rack. The hole is off by about .030" and I believe there is probably enough metal
? ? above the hole in the rack to fit. I am not sure what the rack is made of. It seems like
? ? steel which I don't think is hardened. But I don't really like the idea of changing the?
? ? rack this way.
3. Fill the hole with JB Weld or some other sort of epoxy-like filler and then re-drill and?
? ? tap. I assume this wouldn't be as strong as drilling the holes in new locations (i.e., #1 above)
? ? but I don't think this will be a concern. I haven't tried moving holes this way before so I am
? ? not sure it will be easy to move the holes a small amount like this.
I would like to get some advice on what is the best way to correct this. Thanks.
Tom
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??? ??? Just watched this last night . It may work for your
problem .
??? ???
??? ??? animal
On 1/14/2022 2:21 AM, drmico60 via
groups.io wrote:
toggle quoted message
Show quoted text
Hi Tom,
I have tried your suggestion 3 and the problem is that the drill
cuts the epoxy much faster than the steel and this forces the
drill bit to follow the original hole. The best way I have found
is to fill the holes with some steel screw threaded bar leaving a
little protruding. Put some epoxy on the screw thread when fitting
the screw. Allow the epoxy to set and then file the steel flush
with the surface. Centre punch the new hole position and re drill
the hole.
Mike
|
On Fri, Jan 14, 2022 at 08:50 AM, Jeff Lott wrote:
Try modifying the bolt for that one hole with a step/recess in a portion of the thread and turn the head undersize. I assume it is a SHCS.
?Hi Jeff. If I understand correctly, this would require making part of the SHCS narrower. I am not sure this would work because the screw that hold the rack to the lathe are only M3. So there is not much metal there to trim down. (Its possible I misunderstood your idea.) Tom
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Thanks everyone for the suggestions. I didn't think of the problem with positioning the new hole close to the original
hole filled with JB Weld. So it sounds like I dodged a bullet there. Thanks.
I plan to try the approach suggested below. Hopefully, I can get it right this time. Thanks again.
Tom
toggle quoted message
Show quoted text
On Fri, Jan 14, 2022 at 03:30 AM, Miket_NYC wrote:
The way I?handle problems like this is to drill the hole significantly larger and tap it. Then insert a bolt that fits the tap, using JB Weld as your thread-locking compound.? Once that sets, saw off the bolt level with the surface.??
?
Now, your original hole is gone and you have new metal at the location, so you can drill and tap it in the proper place with no worries.? (If it would be difficult to saw off the bolt level with the surface, you can instead saw the top of the bolt off ahead of time and manipulate the cut place it to be level with the surface before the JB Weld sets).
?
Mike Taglieri
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You could probably get away with it, by working up in drill
Thanks everyone for the suggestions. I didn't think of the problem with positioning the new hole close to the original hole filled with JB Weld. So it sounds like I dodged a bullet there. Thanks. I plan to try the approach suggested below. Hopefully, I can get it right this time. Thanks again. Tom On Fri, Jan 14, 2022 at 03:30 AM, Miket_NYC wrote:
The way I?handle problems like this is to drill the hole significantly larger and tap it. Then insert a bolt that fits the tap, using JB Weld as your thread-locking compound.? Once that sets, saw off the bolt level with the surface.??
?
Now, your original hole is gone and you have new metal at the location, so you can drill and tap it in the proper place with no worries.? (If it would be difficult to saw off the bolt level with the surface, you can instead saw the top of the bolt off ahead of time and manipulate the cut place it to be level with the surface before the JB Weld sets).
?
Mike Taglieri
--? Bruce Johnson
"Wherever you go, there you are." B. Banzai, PhD
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Ugh, bumped the send!?
...by working up in drill size, start with a small hole entirely in the steel, that way the larger bit will be a lot less likely to wander.
You could probably get away with it, by working up in drill
Thanks everyone for the suggestions. I didn't think of the problem with positioning the new hole close to the original hole filled with JB Weld. So it sounds like I dodged a bullet there. Thanks. I plan to try the approach suggested below. Hopefully, I can get it right this time. Thanks again. Tom On Fri, Jan 14, 2022 at 03:30 AM, Miket_NYC wrote:
The way I?handle problems like this is to drill the hole significantly larger and tap it. Then insert a bolt that fits the tap, using JB Weld as your thread-locking compound.? Once that sets, saw off the bolt level with the surface.??
?
Now, your original hole is gone and you have new metal at the location, so you can drill and tap it in the proper place with no worries.? (If it would be difficult to saw off the bolt level with the surface, you can instead saw the top of the bolt off ahead of time and manipulate the cut place it to be level with the surface before the JB Weld sets).
?
Mike Taglieri
--? Bruce Johnson
"Wherever you go, there you are." B. Banzai, PhD
--? Bruce Johnson
"Wherever you go, there you are." B. Banzai, PhD
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Tom,
I had a similar issue with my MicroMark 7x16. I had two issues contributing to the poor mesh of the rack and pinion gear. (1) I moved the rack down for a better fit as others have done. (2) The pinion gear was bad fit in the hole in the apron. I took the apron off and bored out the pinion gear hole and turned up an oilite bushing to fit the bored out hole. This removed the sloppy fit between gear shaft and ?apron bore. This made a dramatic improvement to the rack pinion mesh. The sloppy feel is gone.
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That was the idea. I didn't know the size of the bolt.
On Friday, January 14, 2022, 01:48:42 PM PST, <thomasfkeefe@...> wrote:
On Fri, Jan 14, 2022 at 08:50 AM, Jeff Lott wrote: Try modifying the bolt for that one hole with a step/recess in a portion of the thread and turn the head undersize. I assume it is a SHCS.
?Hi Jeff. If I understand correctly, this would require making part of the SHCS narrower. I am not sure this would work because the screw that hold the rack to the lathe are only M3. So there is not much metal there to trim down. (Its possible I misunderstood your idea.) Tom
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Couldn't resist injecting a bit of humor on this subject. Drawings from the Lawrence Radiation Lab, ~50 years ago!
On Fri, Jan 14, 2022 at 9:07 PM Jeff Lott via <tall_guy_lott68= [email protected]> wrote: That was the idea. I didn't know the size of the bolt.
On Fri, Jan 14, 2022 at 08:50 AM, Jeff Lott wrote: Try modifying the bolt for that one hole with a step/recess in a portion of the thread and turn the head undersize. I assume it is a SHCS.
?Hi Jeff. If I understand correctly, this would require making part of the SHCS narrower. I am not sure this would work because the screw that hold the rack to the lathe are only M3. So there is not much metal there to trim down. (Its possible I misunderstood your idea.) Tom
-- Don't underestimate birthdays.
It seems like the people who have the most of them live the longest....
Sent from my antique Win7 desktop
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When I moved my rack I made a pilot sleeve for both the drill and tap. With the rack clamped in place I was sure to have accurate tapped holes. Paul M
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OldToolmaker
