Hi All,
I wanted a VMS 70 but my budget does not stretch that far so I decided to make one.
I was thinking about it & all my machining equipment dates from the 50s to the 70s... which is VMS territory.
I think I'm about 75% of the way there.
Its half scale because my crucible isn't big enough to cast a full size VMS body and.... I don't have that much interest in cutting LPs anyway.
Cutting head wise, I'm going to have a go at making a KNOP REC1 as its the best documented head making thread on this forum.
Main spindle motor? No real firm decision yet. Might make one.
Cheers,
Wilson.
Half scale VMS 70
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Half scale VMS 70
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dubcutter89
- Posts: 359
- Joined: Thu Oct 19, 2006 6:30 am
- Location: between the grooves..
Re: Half scale VMS 70
New year but to me this already is the best DIY project 2021 
Cheers
Lukas
Cheers
Lukas
Wanted: ANYTHING ORTOFON related to cutting...thx
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leemichael
- Posts: 55
- Joined: Mon Jul 13, 2020 1:43 pm
Re: Half scale VMS 70
Following this thread like a mofo!
Re: Half scale VMS 70
Yes ! Actually that was quite easy. The leadscrew for the vertical slide was actually the hardest part and machining the leadscrew nut.
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Re: Half scale VMS 70
This is a short video of my friend grinding the main dovetail ways.
My grinder is a bit small and moreover it is not automatic like his.
The Neumann VMS would have had it ways ground in a very similar manner on this sort of machine.
In keeping with the project this grinder also dates from the 70's
https://youtu.be/lTydad2PU5k
My grinder is a bit small and moreover it is not automatic like his.
The Neumann VMS would have had it ways ground in a very similar manner on this sort of machine.
In keeping with the project this grinder also dates from the 70's
https://youtu.be/lTydad2PU5k
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Re: Half scale VMS 70
You will need a way to adjust the platter as it need to be ultra flat.
Re: Half scale VMS 70
You mean with reference to the cutting head?
Yes. I was going to just make the spindle a good fit but now that you mention it... some adjustment capability would not hurt I suppose.
What adjustment facility did the VMS have?
Thanks,
Wilson.
Re: Half scale VMS 70
Vms has 2 platters...the top platter sits on 3 bolts in the bottom platter
Re: Half scale VMS 70
Interesting... and you can use the 3 bolts to level the top platter?
Man... I know that theoretically 3 point levelling systems are better than 4 point levelling systems ( 3 point cannot rock ) but actually using them is a total nightmare.
My tool makers microscope has a 3 point levelling system (its German, from the 40's) and it was horrible to get levelled.
It says "OMT" but its actually a re-badged Zeiss Jena microscope recovered as "spoils of war".
Man... I know that theoretically 3 point levelling systems are better than 4 point levelling systems ( 3 point cannot rock ) but actually using them is a total nightmare.
My tool makers microscope has a 3 point levelling system (its German, from the 40's) and it was horrible to get levelled.
It says "OMT" but its actually a re-badged Zeiss Jena microscope recovered as "spoils of war".
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Re: Half scale VMS 70
There is a trick to a three point system.
Mount your dial indicator on the swan neck, and wind it in until it is at the same diameter as your three adjustment screws.
Rotate the platter until one of the screws is directly under the DTI probe, note reading, this is your reference.
Rotate to put next screw directly under the DTI, adjust to match reference reading.
Do this one more time for the third screw, then go back and check, but it should be job done.
Basically you use the fact that the point directly above and in line with the adjuster is controlled only by that adjuster, it is static with respect to the others.
Were I doing another platter I think I would probably place marks on the upper surface to make doing this easier.
Incidentally if doing the three point ball ended screw thing, bal-tec have some useful kinematic components. I would note that you really want two V blocks and a flat, not three V blocks (A mistake I made).
Mount your dial indicator on the swan neck, and wind it in until it is at the same diameter as your three adjustment screws.
Rotate the platter until one of the screws is directly under the DTI probe, note reading, this is your reference.
Rotate to put next screw directly under the DTI, adjust to match reference reading.
Do this one more time for the third screw, then go back and check, but it should be job done.
Basically you use the fact that the point directly above and in line with the adjuster is controlled only by that adjuster, it is static with respect to the others.
Were I doing another platter I think I would probably place marks on the upper surface to make doing this easier.
Incidentally if doing the three point ball ended screw thing, bal-tec have some useful kinematic components. I would note that you really want two V blocks and a flat, not three V blocks (A mistake I made).
Re: Half scale VMS 70
Thanks for the tips on setup.
My microscope has a levelling bubble which is hard to use.
Setting the bubble correctly means levelling to the floor, which may not be level with the table surface(!).
But for recording lathes you're setting the platter with reference to the cutting head so that's a great tip, thanks!
Cheers,
Wilson.
My microscope has a levelling bubble which is hard to use.
Setting the bubble correctly means levelling to the floor, which may not be level with the table surface(!).
But for recording lathes you're setting the platter with reference to the cutting head so that's a great tip, thanks!
Cheers,
Wilson.
Re: Half scale VMS 70
Having a fixed reference really helps.
One other thing to watch is that the cutting head needs to travel at an exact right angle to the spindle axis, otherwise the depth of cut changes with diameter.
On a VMS clone you could possibly tweak this out electronically using the depth control coil, but providing some reasonably convenient way to shim the thing might be worthwhile. My main ways (THK Cross roller bearings in mine) are mounted on a 'hinge' at one end with a 100tpi screw to trim this out.
Not having access to a decent machine shop at the moment (So envious!), my build is being based on used semiconductor fab photonics parts (Good source for really nice positioning slides and the like), and mostly a mix of ground flat stock and ally tooling plate (Because both are actually ground flattish from the factory).
The local water jet cutting place is getting far too much of my money.
Regards, Dan.
One other thing to watch is that the cutting head needs to travel at an exact right angle to the spindle axis, otherwise the depth of cut changes with diameter.
On a VMS clone you could possibly tweak this out electronically using the depth control coil, but providing some reasonably convenient way to shim the thing might be worthwhile. My main ways (THK Cross roller bearings in mine) are mounted on a 'hinge' at one end with a 100tpi screw to trim this out.
Not having access to a decent machine shop at the moment (So envious!), my build is being based on used semiconductor fab photonics parts (Good source for really nice positioning slides and the like), and mostly a mix of ground flat stock and ally tooling plate (Because both are actually ground flattish from the factory).
The local water jet cutting place is getting far too much of my money.
Regards, Dan.
Re: Half scale VMS 70
A bit of lead screw porn...
You can see the buttress thread form in this pic:
It was single point cut with a VNMG insert reground to a 45 degree buttress thread form.
You can see the buttress thread form in this pic:
It was single point cut with a VNMG insert reground to a 45 degree buttress thread form.
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Re: Half scale VMS 70
Good point.
Fortunately years of hoarding seemingly useless items has paid off.
This is an OMT 14" Optical Table. It looks like a rotary milling table but is it not.
It is a reference instrument for precise alignment of mirrors, lenses, lasers, and other optical components.
It is accurate to 1/3 of 1 arc second.
Which is probably a bit overkilly but it'll certainly do the job!
Speaking of useless... in the top right of the picture is the last Blume & Riedecker Mk4 coil winder in existence.
It winds basket weave coils which used to be necessary for radio equipment.
Sadly its function now is purely ornamental.
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Re: Half scale VMS 70
That coil winder might be of mainly historical interest for coils, but load it up with some aramid yarn and I bet you could get it to make small pressure vessels and maybe even things like wound high pressure tubes.
Besides, basket weave litz wound plate chokes are still a thing in some circles.
Besides, basket weave litz wound plate chokes are still a thing in some circles.
Re: Half scale VMS 70
Oooh... that's an interesting idea. I have a load of kevlar offcuts from when I worked with some ballistic armour people (https://sarkartactical.com/)
You can pull threads off the edge quite easily before its embedded in resin or whatever.
Hmmm... anyone for a kevlar torque tube ?
You can pull threads off the edge quite easily before its embedded in resin or whatever.
Hmmm... anyone for a kevlar torque tube ?
Re: Half scale VMS 70
Kevlar, carbon fibre, all sorts of things you can get as thread.
I sort of wonder about a basket wound voice coil, better cooling but unfortunately the fill factor would be horrible.
Back in the early days of firearms (Think early cannon) the wire wound barrel was actually a thing for a while, basically because wire was easier to inspect then castings made with really random metallurgy in an age before xray and ultrasonic flaw detectors.
I sort of wonder about a basket wound voice coil, better cooling but unfortunately the fill factor would be horrible.
Back in the early days of firearms (Think early cannon) the wire wound barrel was actually a thing for a while, basically because wire was easier to inspect then castings made with really random metallurgy in an age before xray and ultrasonic flaw detectors.