What considerations apply to material selection for cartridge mounting bolts?

@richardbrand  on mounting problems

The SME 3009 improved and Shure V15 mk3 was right up my street in the 70s, along with the Garrard 401 and SME plinth system. The whole rig was quite the standard go to front end. I found the V15 mk2 was more forgiving with vinyl imperfections.

SME offered as an upgrade at the time, nylon nuts and bolts to cut down mass just after the “improved” arm launch. I went down that road which was against the bolt everything up as tight as possible norm. I never noticed a difference to be honest. 
 

I tried recently to put my V15 mk3 back into service and had the same problem with needing longer bolts. The cartridge is not very strong laterally as metallic nuts and bolts can distort the shell as washers larger than the bolts don’t fit. There’s no spare diameter to ensure a more secure fix. The nuts can slip sideways (as not captive) out of the mount. The plastic is then compromised forever.
 

l never thought the cartridge worked anywhere near spec using compatible after market styli. The Shure “trackability” was just not there. The new stylus would not track their test record at the highest modulations like before.

Good luck with your quest to get this classic cartridge up and working again. My cartridge ended going back into stock. After l first retired the V15, l started using a Goldring G900IGC that runs to this day, having a spare NOS stylus in reserve..

And these people sell M2.5X20mm,  a bit longer than you need for around 20 bucks US. Here

@lewm 

I posted a big thank you a bit earlier, but Audiogon swallowed it!

Your offer is extremely generous, and much appreciated, but I am in operation with two overlong and over-skinny bolts my local dealer gave me.

When I went to the website page you first recommended, I discovered some hex socket bolts in 20-mm and 25-mm lengths, so I ordered 10 x 20-mm ones for just over AUD-20, delivered next year.  Alas, not gold plated.

Now I am wondering if the 20-mm includes the head or not.  Emails will be going to China.

By the way, Chinese exports to Australia jumped 35% last year, due to the t-word.

Now if you happen to spot any DS Audio cartridges and equalisers in Akihabara ... ;-)

For stuff like DS Audio, you have to speak very good Japanese and gain the respect of the sales people who typically speak zero English.  My son can do that; I cannot. With his help I was able to score the Koetsu Urushi about 15 years ago, but the days I go shopping are days he has to go to work, so lately I shop alone. I cannot discuss T without risking a cardiac death.

@mylogic 

My Garrard 301 was given to me by my Dad, as it happens the last time I saw him.

It included the SME plinth, which I have very extensively modified inside (you probably cannot see any differences from the outside).  I've done a fair bit of work on the Garrard, replacing the main bearing and most of the service parts like springs and idler.  

I've not done anything to the SME except mount and dismount it and resolder a connector.  Maybe that's where I came across nylon bolts.  Clearly SME did everthing possible to get the effective mass down.

I could buy a complete Audio Technica VM540ML cartridge cheaper than a Jico SAS/B stylus for the Shure.  With the Audio Technica, the Garrard / SME sounds broadly as good as CDs to me.

@lewm suggested vinyl could be much better, and I did buy the Jico but never got the chance to fit it.  Then Holbo came up with their direct sales model and I could not resist the combination of air platter bearing, air tone arm bearing, tangential tracking and ridiculously low price!

My Shure was lying around so in went the Jico and eventually it got bolted to the Holbo.  I did have some washers, and fitted the bolts upside down with washers top and bottom.  The Jico stylus picks up a lot less surface noise (groove wear?) with its micro-line diamond compared with the elliptical Shure stylus.  I still have it, and it would be a very easy swap.

I have bought an expensive cable for the SME arm - no joins in between the cartridge and the pre-amplifier, and balanced.  When I get the Holbo singing, I'll be pulling wires through the SME.

For what it is worth, I removed most of the hardboard bottom of the SME plinth, reinforced the corners with Aussie ironbark gussets, and filled the interior with three thick MDF slabs, cut out where necessary. The slabs are separated with constrained layer damping, and the motor board sits on the top slab.  The slabs in turn sit on three IsoAcoustics OREA Bordeaux isolators.  The outer plinth is air gapped from this inner structure.  I have designed the changes so the motor-board can be sprung from the outer plinth, but I have yet to feel the need to do this.