Var Preciray Truing Jig - Instructions Needed On How To Use It

[Greengoguy]

Hi, does anyone have knowledge on how to use the Var Preciray Truing Jig?
I have purchased one, but I don't have any instructions on how to operate it!
I have searched Google, to see if there may have been a manual in pdf format, but I couldn't find one.

 

[I like Skol]

Have you ever built or trued a wheel?

I've never used a wheel jig as I always just use an upturned bike with bits of sellotape and cable ties as reference points, but I always assumed the wheel jig would just be an improvement on that and it would be fairly obvious?.....
Having built a few dozen of wheelsets over a number of decades I never felt it was necessary to acquire a wheel jig.

 

[Greengoguy]

Hi Skol, it's always been something of a dark art to me, how to true a wheel without a jig or at least a dial!
I have trued a few wheels, but not very accurately. I haven't yet built a single wheel!
I really like this vintage Var Preciray; it has the dials for lateral and radial truing, at the same time.
I'm very keen to learn how to use it.
Have you seen one?

 

[hatler]

I can recommend this book - https://www.wheelpro.co.uk/wheelbuilding/book.php

 

[Darius_Jedburgh]

Have you ever built or trued a wheel?

I've never used a wheel jig as I always just use an upturned bike with bits of sellotape and cable ties as reference points, but I always assumed the wheel jig would just be an improvement on that and it would be fairly obvious?.....
Having built a few dozen of wheelsets over a number of decades I never felt it was necessary to acquire a wheel jig.

Not a very helpful comment to a new member, considering he already has the jig.

 

[dan_bo]

Not a very helpful comment to a new member, considering he already has the jig.

And yours is?

 

[Big John]

That's one serious piece of kit and would normally be used by a master wheel builder. I've got a Park truing stand which by comparison is a pea shooter compared to an automatic weapon. Keep hunting on the net. If it'll do the basics, ie lateral and radial truing, without using the dials then you'll be fine. There's a place called The Birmingham Bike Foundry (Google them) and it might be worth giving them a ring. Persevere because that kit is a work of art.

 

[Ajax Bay]

 

[andrew_s]

Good luck with searching, but instructions are unlikely as the Preciray pre-dates the internet.

To work properly, the rollers should be positioned to match the intended position of the rim, and not taken from an un-true wheel.

The radial roller position is fairly simple as the height of the edge of the rim above the bead seat doesn't vary much, but the lateral roller needs to allow for the width of the rim as well as the hub OLN dimension. For example, if the hub OLN is 130 mm, and the outside rim width is 26 mm, the edge of the roller should be (130+26)/2 = 93 mm from the face of the wheel clamp opposite the roller, or (130-26)/2 = 52 mm from the roller-side wheel clamp face. Hopefully the scales that aren't properly visible by the name plate and at the bottom will help with this.
I'd suggest putting a known good wheel in, and seeing what the various scales seem to show.

Brief notes from someone who's used one here

 

[md1xdjw]

Hi, I have one of these with the original instructions. I’ll get it scanned and post a .pdf.

 

[md1xdjw]

 

[md1xdjw]

Photos of instructions below. I’ve never actually read them before - I was taught by my Dad about 35 years ago. In short: insert your wheel, align rollers and gauges by adjusting arm and table. slowly spin the wheel to find an average spot, hold a spoke at this point and flip the wheel, this will give you the ‘error’ in your average spot which you can now eliminate by moving the gauge table (quadrant in the instructions) by half the amount. Away you go. You can true the wheel tightening or loosening spokes according to the bosse or fosse. I imagine the reference to measurements is useful if you are a professional wheel builder making multiple sets.

 

[Sittingduck]

View attachment 590149

is that burnt on gravy in the wheel rim?

 

[Ajax Bay]

Tub glue, I suggest (image was from t'net).

 

[samsavvas]

Hi, does anyone have knowledge on how to use the Var Preciray Truing Jig?
I have purchased one, but I don't have any instructions on how to operate it!
I have searched Google, to see if there may have been a manual in pdf format, but I couldn't find one.

I too have never seen a Preciray, BUT I do have a marvellous 'desk top' wheel truing/building jig built by a friend of mine that uses the same principles as the Preciray but weights about 1/10th of its weight. Like the Preciray it's 'self-catering' - once the hub & rim widths are 'dialled in' it automatically builds in the appropriate dish for the rear wheel. It also caters for a variety of hub widths. the direct reading dial read-outs are by s/s bike spoke dials and allow adjustment to about 0.25mm (if you are so inclined & sufficiently skilled - I'm only good for about 0.5mm!) Mine has been modified (at my suggestion) for added rigidity at the hub-holder, although this is hardly needed given the whole thing is build out of 1" square steel tube, 1" wide plate & heavy machined rod & tube stock. Peter built 7 of them for a professional bike mechanic course he used to run.

The point of this post is simply to say that the Preciray should be very simply to use once you set the rollers for the rim size & dial in the hub & rim widths. I think you'd have to go to something like the CentriMaster to get a stand that operates in this way these days. I'll post a picture of my stand once I'm allowed to...