technics SP-25 armboard

I need to a adapt an Audioquest PT-5 tonearm to a Technics SP-25 turntable base. The round hole is pre-cut to 5 1/2" in diameter and 3/4" deep on the table base. I could buy the official, original armboard but it is designed especially for the EPA-500 tonearm assembly and would need to be adapted for the Audioquest arm. It might be cheaper to build one from scratch with all the correct measurements. Any suggestion will be appreciated.
I have one about that size; I use to be a Technics dealer when the SP-25 was new and had some of them. Is the armboard black by any chance? It is probably for another table but just don't remember.
Sharpe, I was confronted with the same problem. My plinth
is for both: the SP 10 and the SP-25. The armbase is drilled for the EPA 500. To build one 'from scratch' will not be easy. Those are thick (3cm?) and complex armboards to make.Ie expensive. My solutions was to buy the Lustre GST 1 tonearm and adjust the armboard accordingly. The Lustre has SME like base and you will need to do some woodwork to get the arm in the right position. Be very careful with spindel- pivot distance. The advantage is that you don't need some other or new armboard. BTW you can sell your Audioquest arm and buy the Lustre more easilly.

Nandric, did you meant SP-15? I believe that and the SP-25 require the same cut out, thus fit into the same plinth. The SP-10 and SP-10 Mk 2 and Mk 3 have a different pattern, thus fit into a different plinth.

For the OP, it should not be difficult to fabricate a new armboard to drill for the PT-5. The main question may be should he utilize marine ply, solid hardwood, aluminum, acrylic, etc.?
Hi Stanwal:
The official Technics armboard is the black pre-drilled EPA-B500.
I have one installed in a SL-1015 with the EPA-A501H straight titanium tonearm and stem. It is a great arm but seems to be designed for light weight cartridges only as my Rondo Blue is too heavy. I currently have a Denon DL-160 mounted on it and it sounds great.
Rather than try to adapt the official Technics armboard for the SP-25, it may be easier to custom build an armboard out of maple or oak and use the EPA-B500 as a template for the outer dimensions and mounting holes only and position the stem hole to accept the Audioquest PT-5 arm.
Dear Priso, My plinth is SH 10 B4 for SP 20 and SP 10 mk II. One should always check. You are right SP 25 was wrong. The hole in the arm board was 4 cm diameter and I was able to adapt this armbase for the Lustre tonearm. I own 4 other tonearms but for each of those I would need a new armboard. I am pretty sure that this armboard was meant
for the EPA 500 .

Dear Sharpe, As far as I know you can get 2 extra armwands
for your EPA 500 and then use whatever cart you like. The
'S' kind extra will also do. But Stanwal should know better I assume.

They had either 2 or 3 aditional arm wands designed for heavier cartridges but they would be hard to find, although I did see one a couple of years ago. I had an EPA 500 in the 80s and it is a great arm. You could add mass to your counter weight if you wanted to use heavier cartridges but the wand/cartridge interaction would not be ideal.
Way back in 2006 I bought blank SP-15/25 armboards from Russell Collins:

It's worth an email to see if he's still around and can source them.

Technics used the motor unit model number in identifying their dedicated plinths. From what I found on Vinyl Engine, there are four plinths for the SP-10 Mk2 --SH-10B, SH-10B3, SH-10B5, and SH-10B7. They differ in year of manufacturer, construction and mass.

The SP-15 motor unit had two plinth options -- SH-15B2 and SH-15B3.
Hey guys...thanks for all your suggestions! I solved all my problems by throwing more money at it. I broke down and purchased a used Technics EPA-B500 arm base with an EPA-250 tonearm from an analogue specialist based in Hong Kong. This arm is an "S" shaped and features a removable headshell (great for cartridge changing). I was able to sell my Audioquest PT-5 on ebay for a nice profit helping defray the cost of the Technics arm. Listening as I type this and it sounds great. Nothing like the real thing!