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 Post subject: Ultra-tec V5 adjustment issue
PostPosted: Thu Mar 14, 2019 3:25 am 
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I bought a new Ultra-tec V5 a few years ago to replace an old Prismatic protractor machine. I’d cut a lot of stones on the Prismatic, but the allure of 0.01 degree accuracy proved too much to resist. I’ve generally been delighted with the V5. The mast is a tour de force of machining accuracy, and the angle repeatability makes the whole faceting process much easier. I had noticed, however, an angle variation when sweeping across the lap. Recently I decided to get to the bottom of this, and to make a long story short the lap was definitely not rotating in a plane perpendicular to the mast. To test this out, I mounted a dopped stone with a finished table in the 45 degree adapter, and set the digital angle to 45.00 degrees. There is enough reach, if the mast is slid close to its track end, to touch the stone at the twelve and six o’clock points on an 8” lap (viewed from above). The three o’clock point isn’t a problem. The variation between the three points was about 0.15 degrees, not an insignificant amount. I had expected there to be some adjustment so the lap could be tuned to rotate perpendicular to the mast, but there is nothing (unlike on the old Prismatic). Both the drive shaft and the mast use the flat base plate as a reference, with the drive shaft flange secured to the base by three sturdy bolts at 12, 4 and 8 o’clock positions. The only solution was to back off the bolts and install shims under the drive shaft flange between the bolts, but how to find material thin enough? It turns out that aluminium cooking foil is just about right, and can be folded to adjust the thickness quite accurately. By some trial and error it was possible to eliminate the variation, and the lap now runs truly perpendicular to the mast. I was, by the way using one of Gearloose's laps, so lap flatness was not an issue.
I'm frankly more than a little surprised that this whole exercise was necessary, but other faceters may have noticed the same issue with the V5. I hope this remedy proves helpful.


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 Post subject: Re: Ultra-tec V5 adjustment issue
PostPosted: Thu Mar 14, 2019 1:40 pm 
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Joined: Tue Mar 27, 2012 10:15 am
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Location: Cary, NC
Salik,

Thank for the heads up and solution. I just purchased a V5 and its supposed to ship on April 5th. One thing I've seen done in the car world for these types of situations is just to purchase one of those $5 metal feeler gauges, find the right one and then sacrifice and snip :)

My thanks for passing this on and I'll test mine when I unpack and adjust :)

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Bob Hodges

Faceter: When turned into a zombie, they stumble around crying "roooouuuuggghhhh"


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 Post subject: Re: Ultra-tec V5 adjustment issue
PostPosted: Thu Mar 14, 2019 4:53 pm 
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Hi Durnik. I thought of that solution as well, and I've got some 0.001" brass shim stock, but it's much too thick for the job. The aluminium cooking foil is much thinner, and really worked very well. I'll be interested to hear if your machine has the same issue.

Salik


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 Post subject: Re: Ultra-tec V5 adjustment issue
PostPosted: Fri Mar 15, 2019 1:02 pm 
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On Ultra Tec faceting machines the three screws on the riser block are there to adjust the vertical axis of the swivel to be parallel to the platen spindle. You first loosen the screw in the direction you wish to move the swivel axis, a tiny bit, then tighten the other two screws. This is an iterative procedure. You don't need to shim the drive shaft assembly.


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 Post subject: Re: Ultra-tec V5 adjustment issue
PostPosted: Fri Mar 15, 2019 1:17 pm 
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Duncan,

Is this documented somewhere (hopefully with pictures)? Mine should be here in 20 or so days and I have some table saw alignment tools I can use to check for run our and level.

Thanks a bunch :)

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Faceter: When turned into a zombie, they stumble around crying "roooouuuuggghhhh"


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 Post subject: Re: Ultra-tec V5 adjustment issue
PostPosted: Fri Mar 15, 2019 4:05 pm 
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Duncan.
Thanks for this info. I agree with Durnik - is this documented anywhere? There must presumably be some compression feature in the riser block.

Salik


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 Post subject: Re: Ultra-tec V5 adjustment issue
PostPosted: Sun Mar 17, 2019 10:48 pm 
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Jay Conner posted a drawing on this a while back that was very helpful. Maybe he will see this and repost.


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 Post subject: Re: Ultra-tec V5 adjustment issue
PostPosted: Tue Mar 19, 2019 9:16 am 
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salik wrote:
Duncan.
Thanks for this info. I agree with Durnik - is this documented anywhere? There must presumably be some compression feature in the riser block.Salik

Unfortunately I can't find an illustration of this orocess in the Ultra Tec documentation or on the web. There is no compression feature in the riser block. The faceting head is attached to a cylindrical sleeve that swivels in an angular protrusion of the riser block. There are two small ball bearings in this sleeve, one at each end, although you can't see them. The top bearing is held in place with a short shaft (with a conical lower end that you also can't see). The upper end of this shaft, which you can see, is held in place with three set screws, protruding slightly from the vertical sides of the riser block protrusion holding the head swivel. Adjustment of these three screws adjusts the vertical orientation of the swivel so that it is parallel to the axis of the platen.

To do this, set the quill at about 45 degrees, jamb a short piece of ordinary pencil in the end, select a flat lap and lower the pencil just to touch the surface of the stationary lap. By sweeping the pencil across the lap you can see if the swivel needs adjustment to the back or front, and by sliding the foot along the base you can see if the swivel needs adjustment right or left. First loosen very slightly, never more than a quarter turn, the screw in the direction you wish to move the top of the swivel, then tighten the other two. Repeat successively until the pencil sweeps the lap evenly. It is a repetitive process and it takes patience to adjust these three screws correctly, but it doesn't involve taking anything apart or modifying the machine.


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 Post subject: Re: Ultra-tec V5 adjustment issue
PostPosted: Wed Mar 20, 2019 1:16 am 
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Duncan: Many thanks for the detailed description. It's really a great help, and essential information if the machine is not correctly aligned. I hope other owners, and new owners see this. It's still a surprise to me that the machine arrived out of alignment in the first place.

Salik


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 Post subject: Re: Ultra-tec V5 adjustment issue
PostPosted: Wed Mar 20, 2019 5:22 am 
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There are many possible causes of misalignment, which is why the three adjustment screws exist. I can think of wear of the swivel bearings, wear of the cone that holds the top bearing, wear of the platen bearings, wear of the base plate, impact during shipping . . . If there is dirt on the platen surface, the bottom of the mast foot, the bottom of the lap, or if the lap surfaces are not parallel and flat, it will also appear that the head swivel is misaligned. It is not necessary to be obsessive about this. Minor misalignment won't affect faceting appreciably. And with use no lap stays completely flat, so you have to compensate for that yourself anyway.


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 Post subject: Re: Ultra-tec V5 adjustment issue
PostPosted: Fri Mar 22, 2019 8:14 pm 
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Location: Wylie Texas but in Alaska for a while
My base was very old and I am not sure if it had adjustment screws or not.
I modified my machine in a few ways to make the adjustment easier:

1) I switched the adjustments so I could do them from the top.
a. If I remember it right, the base plate had clearance holes and the platen assembly had tapped holes.
b. I use the tapped holes in the platen and put in short stainless socket screws to act as the levelers.
c. I rotated the mast assembly so I had clean space for the levelers and clear spaces for new locking bolts.
d. I drilled one hole with the tap drill for a (I think ¼ or 3/8 sixe bolt, whatever the hole in the mast was originally tapped. I also drilled through the base.
e. I then tapped the base
f. And drilled a clearance hole for the mast assembly.
g. I them bolted the mast assembly down to the base, and drilled with the tap drill size for 2 more clamping bolts, tapped the base, and opened the mast for clearance holes.
2) Now I can adjust the mast assembly from the top.
3) I back off the leveling screws,
4) Slightly clamp the mast
5) Put on the facet head to measure the runout.
6) I then adjust the leveling screws, loosening a clamping bolt if needed.
7) I them got everything pretty close (within .03) on the facet head.

I tried everything I could to get rid of the last little bit, but it fought me,

So I tapped the platen in 3 places for a small set screw.

I use an old steel lap and a master lap.

(My platen had a pin in it, so I drilled a matching hole in the steel lap. This allowed me to ensure it was always mounted the same way. )

Now with the steel master lap. I can adjust the final .03 out. My lap reads the same spinning or sweeping.

I have found that when I pack it up and ship it or drive it in an RV to Alaska that it goes out of alignment. But with the screws for adjustment on the top, it is easy to get it back in alignment.


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 Post subject: Re: Ultra-tec V5 adjustment issue
PostPosted: Sat Mar 23, 2019 2:56 am 
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wilsonintexas wrote:
My base was very old and I am not sure if it had adjustment screws or not.
The three alignment adjustment screws are on the riser block of the mast, not the base. They are present on the image of the oldest model I can find on the web http://www.ultratec-facet.com/images/old-v2-head-sml.jpg and every more recent one.


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