I purchased a plastic box with different compartments that came with complete sets of mounting bolts and washers and nuts. There were 4 different lengths of mounting bolts and i mounted my V15 type 4 easily. The screws were stainless steel with and came with the appropriate allen wrench. Got it from Amazon for something like $12.00. I was able to mount 2 of my moving magnet phono cartridges and still have screws left over. The kit also came with both stainless and nylon washers. Search for phono cartridge mounting screws on Amazon. There are a couple of pages of different screws.
What considerations apply to material selection for cartridge mounting bolts?
I have found myself needing some longer bolts to relocate a Shure V15 Type 3 cartridge to a Holbo air-bearing system.
The Holbo tone-arm is a tangential tracker with a rigid rectangular 'launch pad' for the cartridge. The pad is 3-mm thick which is much more than the fixed SME head-shell my dad bolted the Shure to some 45 years ago. If it was supplied with longer bolts, they disappeared decades ago!
I will most likely have a similar issue with my Audio Technica VM540ML cartridge which is probably a better fit for the Holbo. It was supplied with a head-shell 4-mm thick, but the bolts slots are recessed by over 2-mm.
A quick internet search turned up bolts made of stainless steel, titanium, aluminium, brass, plastic and nylon. Some brass bolts are gold-plated (for corrosion resistance presumably). As a one-time metallurgist, I know that stainless steels can be non-magnetic, or magnetic.
Plastic and nylon are lightweight insulators and immune to electro-magnetic effects like induced eddy currents.
The lower the material density, the lower effective mass of the cartridge. Here brass is clearly the worst, being denser than steel and weaker than the other metals.
I presume that the main engineering requirement is to firmly couple the cartridge to the tone-arm but I have no idea how firmly.
The Funk Firm has an opposite view with its Houdini coupler which in effect splits the bolts in half, with an elastic suspension between the cartridge body and the tone-arm. It seems to allow the cartridge body to swing easily to the left or right side. Does anybody here use these?
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Cartridge Companies have been through every concept for the needs of a Cartridge during the Hey Day for Cart's being used. Designs to optimise a Cart's function has continued on from the 80's since the use of a Vinyl medium waned. At no time has I discovered there is a Cart' Body produced from a composite that is a elastomer connection to the Headshell. The Houdini has no attraction, where rigid coupling is the most important connection to be in place. As for Mounting Screws, resonant frequency and weight are also considerations for magnetic avoidance. |
Take a gander at https://korfaudio.com/. He (Korf) has done an incredible amount of measurements of headshells, decoupling spacers, etc... Korf has developed a very good system for characterizing vibrations in the tonearm/headshell/cartridge system and to develop means to dampen them. Very good summary of the mechanical issues involved. And of the solutions he's come up with. Check out his cartridge spacer. He developed this spacer using his test methods. The spacer is quite effective in damping vibrations and is less than half the price of the Funk Firm (and it has measurements to back up its claims). |
After a lot of trials I've found in my system that Titanium screws sound the best, a bit expensive but depending on your system well worth the price. https://acousticalsystems.audio/product/titanium-smart-screws/ |
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