Using Torque Screwdriver on LP12

General HiFi discussion, using the Tune Method to evaluate performance

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Charlie1
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Post by Charlie1 » 2009-02-27 13:01

Good idea Mike - I will do that.

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Post by ThomasOK » 2009-02-27 19:49

Charlie1 wrote:
Lejonklou wrote:you need to remove outer platter, belt and inner platter to get access to the screws.
I did this last night to take a peek. I can see the three screws, but can't quite access enough of them to make an adjustment - the hole in the top plate is slightly too small.

What about the other screws on the top - are any of those worth adjusting?

1.) There are a pair by the motor (that stand proud and not flush with the plate). Perhaps these are what are referred to as the 'motor stud fixings' or are they inside the deck?

2.) Three that correspond to the suspension I would guess.

3.) Finally, there is a large and small fixing close together, both at the top and bottom.
You will have to move the subchassis over slightly to adjust the main bearing screws. If you put the hex head tip in the top of the screw you can push against the top plate to get it in solidly.

1) The pair of hex head bolts by the motor hold it in place and their adjustment does make a difference but you need to get at the underside to hold onto the nut while you adjust them. The two bolts that stand up higher with either PosiDriv or slotted heads adjust speed and shouldn't be messed with unless you know what you are doing. They allow you to change the motor tilt which adjusts where the belt rides on the pulley and therefore the speed. But I have seen a couple of motors destroyed by people taking too heavy a hand adjusting these.

2) I have, so far, not attempted to adjust the torque with which the suspension bolts are attached to the top plate. This is partly a practical matter as you would need an extremely long 8mm socket to be able to do it with the torque screwdriver and I haven't seen one like that. It is also difficult to tighten it without having to take apart a fair bit of the suspension making it difficult to A/B the change. I suppose you could try adjusting form the top with a PosiDriv head but you still need some way to hold the nut on the bottom. My feeling was that this bolt probably wouldn't make a difference as long as it was tight, but I could be wrong. I don't believe that Fredrik has tried these bolts either.

3) The two bolts that hold the top plate to the plinth make quite a musical difference when properly tightened. This you do from the underside and you have to remove the P-Clip that holds the arm cable in the back and the ground wire in the front to get at the nut that tightens the top plate to the plinth. The smaller screws on the side of these are for locating and thread into wood. My experience is that the torque on these makes no difference as long as they are solid. As a matter of fact, the only screws going into wood that I have found a specific torque for are the armboard screws. The others that hold on the Trampolin or that hold the wiring strap to the wood blocks sound the same to me anywhere from just snug to just before the point of stripping them.

It wouldn't be a bad idea to download the Linn setup manual but again I'd be careful. One of my customers did that and he either downloaded somebody besides Linn's idea of a setup manual or he misread it as he was one of the ones who destroyed his motor which he swears he did by "following the directions". Good luck.
Last edited by ThomasOK on 2009-02-28 16:27, edited 1 time in total.

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Post by Charlie1 » 2009-02-27 21:56

Many thanks Thomas. That will help a lot. I need to be careful what I attempt

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Post by Charlie1 » 2009-02-28 00:16

ThomasOK wrote:You will have to move the subchassis over slightly to adjust the main bearing screws. If you put the hex head screw in the top of the screw you can push against the top plate to get it in solidly.
Job done. Two of them were very tight - the third super tight. My allan key was bending under the force. In fact, I was so worried it would shatter I covered the Ekos up to protect it :shock: I didn't think it would ever budge before the tool broke.

I didn't fine tune by ear myself tonight - that can wait - but straight away it was clearly more tuneful. Whist the sound didn't seem to change, timing was better and I was able to better appreciate what was being expressed through the music. I bought Ryan Adam's 'Easy Tiger' a while ago, listened a few times and quite liked a few tracks, but could never get any more from it. These recent fine tunings have opened the door and now I can't get enough of it. No doubt this is partly familiarity now, but the initial breakthrough was clearly as a result of a more tuneful system (IMO). I think that is when I really appreciate the whole hi-fi journey and it makes most sense - i.e. the whole purpose, the expense and all the fiddling about with spanners and tune dems.

Anyway, slightly side tracked there, but there must be quite a difference between a normal well serviced deck and one that's been totally tuned. Those that often find the KDS close or better to an LP12SE might have to think twice with a really fine tuned deck I reckon.

I think this process will soon come to the stage when I'll need to find a UK dealer prepared to tune the fixings as part of a service. I need the new top plate anyway and have enquired to Chris about a plinth. In the meantime, I will continue to very carefully see how far I can go with the torque settings, whilst not owning a jig or having ANY experience with LP12 setups.

Thanks for all your help, especially Fredrik and Thomas.

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Post by poppop » 2009-04-07 18:09

Hi Guys

Been reading this thread off and on, complete with Torque screwdriver, for a while!

Nearly there with the renovation project, but just a question regarding speed adjustment. I take it that the motor is best left a "little loose" until the speed adjustment is finalised with the +/- screws? Then once correct speed achieved, does anyone have a view as to how tight to make the main fixing screws? To be honest it seems to be a very good system, in that once the "rocking" screws are snug against the motor, minimum tightness of the motor bolts seems to result in a very secure fit.
Dont want to go crazy and start deforming the domes etc.

Many thanks
Steve.

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Post by ThomasOK » 2009-04-08 21:25

I have been using .8Nm for the motor mounting bolts. I would try it around there and see what you think.

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Post by poppop » 2009-04-08 23:22

Thanks Thomas.

Ill try that. The settings so far to are: Arm(Rega) through Board 2Nm. Bearing 3Nm. Bolts through top plate 3Nm. Motor corner mod. c. 0.5Nm.
Arm Board to Sole (dont want to start a fight!) 2Nm.

All the self tappers into wood have really been by "feel". Despite filling and glueing all the old holes, I doubt whether the screws would get anywhere near 2Nm.

Denon 110 on its way. I would hope to have a first listen in about 2/3 weeks time.

Steve.

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Post by lejonklou » 2009-04-16 23:28

I agree the wood screws need to be tightened by feel, Steve.

But your number for the 'bolts through top plate' sounds way too high! If you mean the two center bolts (one front and one rear) that goes through the wooden blocks and the metal reinforcement plate inside the LP12, then the nuts shouldn't be tightened more than about 0.8 Nm. I think that 3 Nm would bend the top plate considerably around the head of the bolt.

Perhaps you meant the nuts that secure these bolt to the top plate?

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Post by poppop » 2009-04-18 18:43

Hi Frederik

Yes, Im talking about tightness of the securing nuts to the top plate. I think this has been discussed earlier in the thread - that a long hex socket would be needed. To be honest, I used the torque driver on the screw head and held the nut with pliers! I dont have a long enough hex socket either!!

The nuts which locate onto the crossbrace were again by "feel", as I didnt have a socket which would fit! As you suggest, tightness was really determined by "just before" I preceive the topplate to be indenting!?

What I have done, given the difference it made to the motor corner, is to fit a similar "mod" to the "switch" corner. Again very low tension is required BUT I have found it makes a significant difference to my perceived movement of the corners? It gives a much firmer attachment to the plinth. Whether this is good or bad remains to be heard!!

Steve.

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Post by lejonklou » 2009-04-20 20:44

poppop wrote:What I have done, given the difference it made to the motor corner, is to fit a similar "mod" to the "switch" corner.
Interesting, Steve!

Do you mean that you have welded/brazed a small pillar to the top plate at the switch corner - or do you simply use the switch hole to somehow attach something that you tighten down against the plinth's corner brace?

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Post by poppop » 2009-04-21 18:12

Hi Frederik,

I actually used Araldite "steel fix" - their usual 2 part mix resin. To be honest I was a little disappointed with this product.
It took me 2/3 tries until it "fixed" - which is why I only just apply tension, which is fine as thats all the corners seem to need!

I simply attached a flat "screw head" (ground flat) to an extended hex nut and then bolted through the corner brace. As I say despite using an abrasive and solvent cleaner on the topplate, it took a number of attempts to get them to take.

The reason for doing both was that once the bolts on the brace are tightened, I felt there was a "hollowness" to the fit on both the motor corner and the switch corner. Maybe part of the reason Linn decided to now fit the motor corner mod?
To be honest Frederik,I cant understand why IF there is a problem with the motor corner, why there wouldnt also be a problem with the switch corner??

However, to remove this "hollowness" it seems that "just tight" is enough to work. So given that I dont want to break off the hex nuts - thats just fine!!

One day Ill actually get to listen to how this all sounds - everthing is now fitted. Just need to set the motor, and allign the cartridge. I must admit Im finding the cartridge allignment a bit frustrating. Denon 110 into rega arm.
Its that last tighten, when you check the protractor and youre sure its just moved that fraction of a millimetre during tightening!! LOL.

Steve.

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Post by Mikeg » 2009-04-22 10:05

Interestingly the motor corner bolt is the only one with a recommended torque setting in the Linn set up manual. From memory it is around 0.4-0.6nm

Mike

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Post by poppop » 2009-04-22 18:26

Mike

Thats useful. Ill give that a check later - just to see if Im anywhere near!

So that really is quite low, certainly compared to the 3Nm on the bearing housing etc.


Steve.

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Post by Charlie1 » 2009-05-28 11:17

There has been mention of many LP12 fixings on this thread, but which ones make the most difference to performance? Presume the three screws that secure the main bearing is most important?

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Post by ThomasOK » 2009-05-28 16:41

Charlie1 wrote:There has been mention of many LP12 fixings on this thread, but which ones make the most difference to performance? Presume the three screws that secure the main bearing is most important?
I don't know that any of us have ever tried to rank the relative importance of the various fasteners. For one thing, if you have the tools to do one of them you have the tools to do them all. I would have to say that the fasteners holding the top plate to the plinth are quite important but I don't know if that is because the best torque to use is so much lower than we were originally taught to tighten them or if it has to do with the fact that you are clamping wood, which is compressible, between two pieces of metal. I think it is safe to say that differences of a couple o hundredths of a Nm are audible on any of the fasteners that matter, so I'd have to say they are all pretty important.

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Post by Linntek » 2009-06-16 08:54


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Post by lejonklou » 2009-06-16 09:16

Looks good to me. The range in Nm is just what's needed and the indicated precision is the same as the tool that Thomas recommends.

The Lindstrom's certainly look professional. And expensive - do you know how much they cost?

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Post by Linntek » 2009-06-16 10:42

Hmm.. expensive

Here is a bunch of others

http://www.hinonline.dk/templates/price ... upGuid=138

Expekt about 1000 - 2000 DKR (1400 - 2850 SEK)

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Post by lejonklou » 2009-06-16 11:07

None of them has the necessary range, so you'd need at least two.

A more important problem is that the settings appear to be rough. You need a tool that can be set to any value. The absolute precision is less important, as it always varies between different tools, but the relative (intra-) precision is really needed. You'll end up comparing settings that are very close (like adjusting your speaker position down to a few mm) and you'll want the values to remain the same next time you use the tool.

Why not get the tool Thomas recommends? I searched for an alternative as well, but couldn't find anything that appeared to be better suited to this task.

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Re: Using Torque Screwdriver on LP12

Post by Lingomatik » 2020-10-17 21:15

Does anyone have experience with the torque tools from WERA?

There is a set with three torque tools from 0.3 - 6Nm.

A CAL 36/4 is very expensive in Germany. 0.3-1.2 / 1.2-3 / 3-6Nm

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Re:

Post by Lego » 2020-10-18 08:37

lejonklou wrote:
2009-02-23 20:07
Lego wrote:...as tight as possible ie by standing on the spanner!!
I've done this too. I even got some extra long keys to be able to properly overtighten the main bearing screws of the LP12. :oops:

My only excuse is that I was taught by the professionals to do this, but for some reason it took many years before I started carefully checking the results. And later Thomas appeared and suggested a torque wrench - something I had contemplated, but didn't know what model to get.

I also admit that getting a torque wrench felt like going to extremes. Surely a a good "feel" for how to tighten various fasteners should be enough, no? Once I had done my very first screw with the torque wrench - the height locking screw on my Ekos tonearm - I could hear this was not extreme, it made perfect sense.
Why is this, is it similar to tuning an instrument?
At least the results seem to resemble that. When overtightening fasteners, you get an out-of-tune sound. If they're too loose, the sound gets sloppy. It seems to be a matter of getting all the resonances balanced.
Thanks Fredrik, just saw your reply :0)
I know that tune

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Re: Using Torque Screwdriver on LP12

Post by Tendaberry » 2020-10-20 10:30

Lingomatik wrote:
2020-10-17 21:15
Does anyone have experience with the torque tools from WERA?

There is a set with three torque tools from 0.3 - 6Nm.

A CAL 36/4 is very expensive in Germany. 0.3-1.2 / 1.2-3 / 3-6Nm
Hold out for the CAL 36/4! I waited a few months and finally found an almost new one for about € 65,- from the USA, including postage and VAT.

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