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Hi Keith:
The true
center line of a threaded shaft is very hard to measure, do you
check the major diameter, the pitch diameter, the minor
diameter? (at work I designed sub micro gauges)
Perhaps
switching to a ball bearing spline shaft might work:
It looked
like the rotational back lash was about 13?m, (at the diameter?
I would think the value would be in degrees?) But I think it
would be sufficient for a Unimat.
Carl.
On 11/29/2024 7:05 AM, Peter Brooks
wrote:
toggle quoted message
Show quoted text
On Fri, Nov 29, 2024 at 03:26 AM, Carl wrote:
What about the run-out of the cone on the clamping
screw?
Wouldn't the same screw in the same threaded hole mate at an
identical place every time? ( I honestly don't know!? :-)
?
The accuracy of the run of the groove might be a more
critical factor if we are talking about very small deviations.
?
Anyway...
?
On Fri, Nov 29, 2024 at 05:24 AM, Keith S. Angus wrote:
For example the whole column could rotate on its
base...
A new base collar opens up a whole load more
possibilities... if the bench was freestanding (or at least
had a void underneath it) then the column could descend
through the bench. It might much be easier to build a system
with the triangular gib key into a new base collar, rather
than into an existing milling head. The milling head could
then be rotated to wherever you wanted it, but the key in the
base collar would ensure accurate up/down alignment (and only
one groove required).
?
?
|
Hello:
?
On Fri, Nov 29, 2024 at 08:44 AM, Peter Brooks wrote:
... (on the U3) that the mill at 90 degrees to the bed isn't a good place ...
Yes ...
Thank you for that.
Made me stop and reflect on all that has been posted.
?
That said, it would seem (to me, YMMV) that we have very quickly lost sight of something important.
?
That something is the rather large bundle of shortcomings the U3 milling head and the milling table both have.
Instantly, sow's ear, purse and all that came to mind.
?
Of course, you can think up, design and throw an interesting amount of money into making really clever solutions.
Only to see our efforts thwarted by the rest of the equipment/tooling you are using.
?
The thing is that we will still using the U3 milling head with the crappy spindle bushings, very limited travel, lack of accuracy in the tilt, etc.
And in some cases, the Unimat milling table, an incredibly overpriced item.
Won't go into what it has to offer in the same departments, fortunately it came with the U3 I purchased.
Had I paid what the going price is these days, I would have cut off my right hand. (fear not, I am left handed)
?
This only to say that the solution to what is probably the worst feature the milling head has needs to be in accordance with the rest of the tooling you are using it with. ie: it can only be as good/accurate as the rest of the Unimat machine / tools you are using it with.
?
Lest you want to go down the 'let's improve it' rabbit hole and end up with something like .
See the complete bit .
?
Just a thought.
?
Best,
?
JHM
|
On Fri, Nov 29, 2024 at 12:24 PM, Carl wrote:
Perhaps switching to a ball bearing spline shaft might work
It's not really the right thing for the job, and, after I put in some likely looking figures for the type, diameter, length etc, it came up with a price of $225. But now I think about it I reckon it would need two nuts to give the rigidity, and that put the price up to $355.
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On Fri, Nov 29, 2024 at 02:21 PM, Julius Henry Marx wrote:
... Instantly, sow's ear, purse and all that came to mind ...
Aw shucks... are you a glass half-empty or glass half-full kinda person? (asked in the best possible humour :-)
?
If we wanted something perfect (with deadly accuracy) we probably wouldn't be using Unimats.
?
It is great fun though to think of simple solutions to niggling problems (following the KISS principle principle wherever possible), and the re-alignment of the milling head on the column after moving it is certainly one of them.
?
Human nature is to dig deeper (often down the rabbit hole, as you say) and this has undoubtedly led mankind into all sorts of complex issues of it's own making.
?
I'm unlikely to ever be able to put a groove in my Unimat column but theorising is always fun. I really admire the experience of folks on this forum - although I must admit I don't always understand what they are talking about!
?
Life long learning, as they say.
|
Hello:
?
On Sat, Nov 30, 2024 at 07:30 AM, Peter Brooks wrote:
... a glass half-empty or glass half-full ...
Good question, one I have made to myself many times.
?
The answer I came up with?
That it will always depend on the contents of the glass and (to a lesser extent), the glass itself.
Another rabbit hole ...? 8^¡ã
... (asked in the best possible humour :-)
Of course.
How else?? 8^D
... perfect (with deadly accuracy) we probably wouldn't be using Unimats.
Indeed.
?
Accuracy in this specific field is, as I have come to discover, exponentially expensive.
And it always goes hand in hand with quality in that respect.
?
I am old enough to have seen things being very different, but at one stage beancounters and marketing droids took over.
And that was it.
?
Not that the Unimat 3 was ever an inexpensive machine.
I may have mentioned it in another post: in 04/1980, a loaded hotdog+a small Coke was US$1.00 in NYC.
At approximately the same date, a basic U3 was offered by Blue Ridge for US$345.00+tax and the 150.310 vise for US$48.00.
These days that snack goes for ~ US$7.00 ...
... simple solutions to niggling problems (following the KISS ...
... re-alignment of the milling head on the column after moving it is certainly one of them.
Along with the very limited quill travel, it was the first thing I realised when inspecting the U3 milling my purchase back in 06/2022.
That same week I decided to sell it but then opted to keep it so I took it apart, had it sandblasted and painted in epoxy.
Jury is still out on that decision.
... unlikely to ever be able to put a groove in my Unimat ...
Same here.
Problem is that this is what you have to work with.
(see attached photo)
?
It is a solution I have searched for all over and also posted about on other forums.
It still evades me.
?
The only (easiest to make) workaround I have seen is one, at one time marketed by Hemingway Kits in the UK.
Not available for many years now.
?
This design was a spin-off of one originally intended for the Unimat 3.
... requires no machining of the Column or the Column clamping member.
... can also be rotated about the Column which a keyway in the Column will not allow on the conventional lathe set-up.
Making it will require using the proper tooling to insure that the parts that hold the rod be identical so that the headstock will register perfectly vertical every time. Maybe making one part 2.25x the height, slicing it in two and finishing them?
ie: needs a U3 mill with this same attachment or have the parts made elsewhere.
?
... theorising is always fun.
Yes it is.
But eventually, cold reality (be it in the form of costs or resulting futility) rears its ugly head.
I find it rather frustrating.
?
... admire the experience ...
Yes, so do I.
That said, I sincerely hope my last post has not been taken as any sort of criticism.
If at any point it seemed so, my most sincere apologies to all.
Like I said, just a thought.
... don't always understand what ...
Believe me, you are not alone in that respect.
?
But if you ask you will get an explanation, always.
That in itself is very valuable.
?
Thank you for you input.
Much obliged.
?
Best,
?
JHM
|
Facetious comment from me as usual, but your 1980 U3 would be worth a great deal more in 2024 than 400 x 1980 hotdogs and cokes now. ?You¡¯d probably have to pay a specialist waste disposal company to take the latter away if you hadn¡¯t already buried it under your vegetable patch.
toggle quoted message
Show quoted text
On 30 Nov 2024, at 12:43, Julius Henry Marx via groups.io <sawbona@...> wrote:
? Hello:
?
On Sat, Nov 30, 2024 at 07:30 AM, Peter Brooks wrote:
... a glass half-empty or glass half-full ...
Good question, one I have made to myself many times.
?
The answer I came up with?
That it will always depend on the contents of the glass and (to a lesser extent), the glass itself.
Another rabbit hole ...? 8^¡ã
... (asked in the best possible humour :-)
Of course.
How else?? 8^D
... perfect (with deadly accuracy) we probably wouldn't be using Unimats.
Indeed.
?
Accuracy in this specific field is, as I have come to discover, exponentially expensive.
And it always goes hand in hand with quality in that respect.
?
I am old enough to have seen things being very different, but at one stage beancounters and marketing droids took over.
And that was it.
?
Not that the Unimat 3 was ever an inexpensive machine.
I may have mentioned it in another post: in 04/1980, a loaded hotdog+a small Coke was US$1.00 in NYC.
At approximately the same date, a basic U3 was offered by Blue Ridge for US$345.00+tax and the 150.310 vise for US$48.00.
These days that snack goes for ~ US$7.00 ...
... simple solutions to niggling problems (following the KISS ...
... re-alignment of the milling head on the column after moving it is certainly one of them.
Along with the very limited quill travel, it was the first thing I realised when inspecting the U3 milling my purchase back in 06/2022.
That same week I decided to sell it but then opted to keep it so I took it apart, had it sandblasted and painted in epoxy.
Jury is still out on that decision.
... unlikely to ever be able to put a groove in my Unimat ...
Same here.
Problem is that this is what you have to work with.
(see attached photo)
?
It is a solution I have searched for all over and also posted about on other forums.
It still evades me.
?
The only (easiest to make) workaround I have seen is one, at one time marketed by Hemingway Kits in the UK.
Not available for many years now.
?
This design was a spin-off of one originally intended for the Unimat 3.
... requires no machining of the Column or the Column clamping member.
... can also be rotated about the Column which a keyway in the Column will not allow on the conventional lathe set-up.
Making it will require using the proper tooling to insure that the parts that hold the rod be identical so that the headstock will register perfectly vertical every time. Maybe making one part 2.25x the height, slicing it in two and finishing them?
ie: needs a U3 mill with this same attachment or have the parts made elsewhere.
?
... theorising is always fun.
Yes it is.
But eventually, cold reality (be it in the form of costs or resulting futility) rears its ugly head.
I find it rather frustrating.
?
... admire the experience ...
Yes, so do I.
That said, I sincerely hope my last post has not been taken as any sort of criticism.
If at any point it seemed so, my most sincere apologies to all.
Like I said, just a thought.
... don't always understand what ...
Believe me, you are not alone in that respect.
?
But if you ask you will get an explanation, always.
That in itself is very valuable.
?
Thank you for you input.
Much obliged.
?
Best,
?
JHM
<head_clamp.jpg>
|
I will repeat what I have stated before.? Figure a way to adapt a Sherline column, and all of this gib discuusion can go away.
|
To go full circle, it would still be great to see how you¡¯ve implemented this, Dick!
|
Hello:
?
On Sun, Dec 1, 2024 at 03:40 AM, Peter Brooks wrote:
... would still be great to see how you¡¯ve implemented this, Dick!
Yes, I second that request.
If only to see what the process entails.
?
That said and along the same line, I believe that the photographs I to in a previous post are of a sample or adaptation/clone of an attachment at one time marketed by Hemingway Kits in the UK, not available for many years now.
I have not been able to find any references (ie: brochures, photos, instruction manual, etc.) to it on-line.
?
Q: anyone here ever seen/purchased/made one?
?
Best,
?
JHM
|
John,
Can you point us to the Sherline Column pictures. I am not familiar with that.
Thanks, Dick
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|
I carried one Sherline outside to take this photo to illustrate the vertical column carriage.? No amount of fiddling around or wishful thinking can make the Unimat column comparable.? ?The most recent photo posted here has a Unimat 3 column with a single round guide rod.? I have previously shown a Unimat column with a double rod setup that I made.? The head can still wiggle around slightly.? A column with gibs is inately stiffer.
|
Hello:
?
On Sun, Dec 1, 2024 at 05:08 PM, John Hutnick wrote:
... carried one Sherline outside to take this photo ...
Thank you.
No amount of fiddling ...
If it only were fiddling ...? 8^D
... photo posted here has a Unimat 3 column with a single round guide ...
That's the link I posted of what would seem to be (?) a Hemingway's Kit but I cannot say for sure.
I have previously shown a Unimat column with a double rod setup ...
That I have not seen.
Have any photos you would care to share with us or a link?
?
Thanks.
?
Best,
?
JHM
|
Please refer to message 62282 Feb. 7.
On Sun, Dec 1, 2024 at 3:43?PM Julius Henry Marx via Groups.Io <sawbona= [email protected]> wrote: Hello:
?
On Sun, Dec 1, 2024 at 05:08 PM, John Hutnick wrote:
... carried one Sherline outside to take this photo ...
Thank you.
No amount of fiddling ...
If it only were fiddling ...? 8^D
... photo posted here has a Unimat 3 column with a single round guide ...
That's the link I posted of what would seem to be (?) a Hemingway's Kit but I cannot say for sure.
I have previously shown a Unimat column with a double rod setup ...
That I have not seen.
Have any photos you would care to share with us or a link?
?
Thanks.
?
Best,
?
JHM
|
Hello:
?
On Sun, Dec 1, 2024 at 06:04 PM, John Hutnick wrote:
Please refer to ...
Done, thanks a lot.
I also found these photographs uploaded by Jeff K.:
?
?
It would seem that one guide bar is not enough and may need to be at least between ?10 and ?13mm.
Not willing/able to spend ~US$200 (and all associated costs) for the Sherline solution, this one is food for thought.
?
It may be worth looking into.
?
Best,
?
JHM
|
The system shown in the Jeff K photos is just too much work for me and not not worth the effort. SHF25 Aluminum Linear Motion Rail Clamping Rod Rail Guide Support for 25mm Diameter ShaftI used these parts as my basis.? They were very inexpensive at the time.? I expanded the 2 side guide holes to 8mm -- that's it. I cannot be the only one who thinks that they will never get done!
On Sun, Dec 1, 2024 at 4:54?PM Julius Henry Marx via Groups.Io <sawbona= [email protected]> wrote: Hello:
?
On Sun, Dec 1, 2024 at 06:04 PM, John Hutnick wrote:
Please refer to ...
Done, thanks a lot.
I also found these photographs uploaded by Jeff K.:
?
?
It would seem that one guide bar is not enough and may need to be at least between ?10 and ?13mm.
Not willing/able to spend ~US$200 (and all associated costs) for the Sherline solution, this one is food for thought.
?
It may be worth looking into.
?
Best,
?
JHM
|
Hello:
?
On Sun, Dec 1, 2024 at 07:18 PM, John Hutnick wrote:
... system shown in the Jeff K photos is just too much work for me and not not worth the effort.
If someone knows about that, that is you.
... used these parts ...
... very inexpensive ...
... expanded the 2 side guide holes to 8mm ...
Right.
Thanks for that!
Much appreciated.
?
I will look into it and check the prices on AliExpress.
They are probably made in China anyway and costs of mail/shipping from the US have become very expensive in the last few years.
... I cannot be the only one who thinks ...
Well, you have generously given me a head start. 8^)
?
I'll make a list of what is needed and a couple of sketches.
When I finish with the power drive adaptation, this one is next.
?
Best,
?
JHM
|
?That was a set that used to be sold on Ebay, I think the maker was in Japan and he only made up a couple of them at a time. I have not seen him on Ebay in a long time. To bad, it was a excellent design. ?Jeff
Hello:
?
On Sun, Dec 1, 2024 at 06:04 PM, John Hutnick wrote:
Please refer to ...
Done, thanks a lot.
I also found these photographs uploaded by Jeff K.:
?
?
It would seem that one guide bar is not enough and may need to be at least between ?10 and ?13mm.
Not willing/able to spend ~US$200 (and all associated costs) for the Sherline solution, this one is food for thought.
?
It may be worth looking into.
?
Best,
?
JHM
|
I used material similar to this:?https://www.amazon.com/Linear-Motion-Hardened-Printer-Tolerance/dp/B08GR2N62M/ to replace the guide rods on my SL for use as a lathe, though they were 330mm length, IIRC. Hardened, and chromed. I have a pair of 12mmx600mm rods sitting here, for the DB, which should wind up as a milling machine, if needed. You'll need to grind or drill through the hardened & chromed surface, possibly, depending on what you're using them for. 13-16mm would be marginally stiffer, and might be good for a U3. You can also get linear rails and bearings, which might work better for a milling column.?https://www.amazon.com/ANWOK-SBR20-300mm-11-8inch-Supported-Bearings/dp/B09BQ5FCKT/
I keep looking at that. But I already have way too many projects sitting there on hold...
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement.? SEMPER GUMBY!
Expect in one hand, expectorate in the other. See which one gets full first.
On Sunday, December 1, 2024 at 03:54:42 PM CST, Julius Henry Marx via groups.io <sawbona@...> wrote:
Hello:
?
On Sun, Dec 1, 2024 at 06:04 PM, John Hutnick wrote:
Please refer to ...
Done, thanks a lot.
I also found these photographs uploaded by Jeff K.:
?
?
It would seem that one guide bar is not enough and may need to be at least between ?10 and ?13mm.
Not willing/able to spend ~US$200 (and all associated costs) for the Sherline solution, this one is food for thought.
?
It may be worth looking into.
?
Best,
?
JHM
|
This device brought back a memory of a device years ago called something like UPLA. Does this sound somewhat familiar?
A few were sold on EBay and were somewhat expensive.
--
http://www.homemadetools.net/forum/?OFF-SET-tailstock-center-65965#post105972
?SMALL TURRET TOOL POST PLANS?
?LARGE TURRET TOOL POST PLANS
?MINI-LATHE CARRIAGE LOCK PLANS
?SMALL QC TOOL POST PLANS?
?QUICK CHANGE LATHE TURRET
?MINI LATHE COMPOUND PIVOT MODIFICATION
|
Just looked at a mill for sale - I think it was Schaublin, and definitely not cheap. The round column had a square key on it to prevent rotation but then the entire column could be rotated in its base. This requires a good sized well fitting base, but it gives a good solution regardless of the type of key used. The column could even be square above the base. Can't see a good way to apply it to any Unimat I've ever met.
|
Carl
OldToolmaker
Bill in OKC too