replacing tonearm question?


Hey,
I have a VPI HW-19 MK4 which I love dearly. My existing Sumiko FT-3 tonearm is 20 years old and on its last legs and I want to replace it with a Jelco 750 or 850. Both arms are 9". Would I have to have a new armboard made and drill new holes? Or could I use the existing armboard and hole and just drill new screws? I know I'd havr to factor in the tonearm radius and all the millimeter differences.

I've never done this before so please excuse my ignorance on this.
128x128simao
@noromance

The friction of the bearings, which is very important, in current Jelco has never dropped below 20/25 mg. indeed, to be precise, the tonearm 850 has even worse values than 30mg. (values equal to or similar to bearings from 30/40 years ago) while bearing technology has made great strides.


I think Jelco has lain too far and is resting on the fame it has deservedly built; the manufacturer is lazy and does not want to commit himself to making innovative arms but they always appear the same for many years identical to those built for other brands.
So why is the 850 better than the Sumiko FT3?
@noromance Not yet. It just came in today and I won't have time until this weekend. Will post an update then.
@best-groove: Thanks for the Sumiko tonearm picture - that'll help!
@simao 

the photo is of a standard lifter that I have restored (it is not a Sumiko or Jelco that is exactly the same) but they are practically all the same and simple to disassemble.

@best-groove  In much the same way a 1% THD tube amp sounds better than a 0.05% THD solid state amp, the friction measurements are so low as to not matter. What does matter is how it sounds. The Jelco 850 is radically different from the other gimbal bearing models in that it uses a hardened precision knife edge. My Jelco 750 bested the Sumiko and the 850 is far better than the 750.
@noromance 

If what you say is true, then the manufacturers could use stone bearing balls carved by Fred Flinstones himself if friction isn't important.
The friction heavily affects the suspension of the head, the cantilever, the tracking, going to compromise several elements.
Every detail of an arm is important, but the bearings and clutches they possess must be taken seriously.