401 Plinth

pre65 · Post by **pre65** » Mon Feb 23, 2009 8:32 pm

I finally got round to modding the 401 multi layer BB plinth i made ages ago !

I had made a fundamental error in my design to do with how the plinth was connected to the baseboard (spotted by Paul Barker at the time) and it was languishing,unloved,waiting for inspiration.

I had got some anti vibrational mounts to fit under the plinth,but because the bottom edges were radiused the outer screw holes would not locate proper like.

So i got the router out and did a bit of freestyle routing to make a recess for the three mounts to fit. Now just need to visit Focus for some more 6mm studding and machine the Delrin spacers down a bit to maintain the right height.

http://i111.photobucket.com/albums/n146 ... plinth.jpg

Originally there were to be four mounts but one corner was compromised by the position of the armboard pillars,and after much thought the back mount was placed centrally.

Mike H · Post by **Mike H** » Mon Feb 23, 2009 9:06 pm

My my you have been busy

So is that 3 pieces of threaded studding now? Which means you adjust for to make it proper level?

pre65 · Post by **pre65** » Mon Feb 23, 2009 9:33 pm

The 6mm studding attached to the mounts was there to "line things up" with the holes drilled in the base plate.

The arm board is carried on three delrin pillars (each with a rubber mount) that are secured to the base and "poke through" the plinth.

The 3 holes in the plinth are not much larger than the pillar (precision engineering !!

),the idea was to keep the plinth mass high.

I nicked the idea from someone else but i forget who it was now.

This is the "thing" as it was !

Mike H · Post by **Mike H** » Mon Feb 23, 2009 10:03 pm

Oh I see. I think

pre65 · Post by **pre65** » Mon Feb 23, 2009 10:12 pm

This is a picture of the baseboard with the 3 pillars and arm board. The arm is a Sonus Formula 4 unipivot.

Mike H · Post by **Mike H** » Mon Feb 23, 2009 10:14 pm

Ah-ha...

Dave the bass · Post by **Dave the bass** » Tue Feb 24, 2009 8:25 am

pre65 wrote:This is a picture of the baseboard with the 3 pillars and arm board. The arm is a Sonus Formula 4 unipivot.

Doh, we forgot to straighten that at Fillphest didn't we

DTB

pre65 · Post by **pre65** » Tue Feb 24, 2009 12:23 pm

Oh woe,thrice woe !

Went into the garage to cut down the Delrin spacers on the plinth mounting and the lathe motor is sparking on switch on, tripping the main trip switch !

Was thinking of buying a better/bigger lathe anyway.

Mike H · Post by **Mike H** » Tue Feb 24, 2009 6:12 pm

WD40?

pre65 · Post by **pre65** » Thu May 07, 2009 2:19 pm

Now the new lathe is up and running (had to take it all apart so I could lift it out of the van) the delrin spacers have now been machined.

Also the holes in the plinth for the 401 mounting studs have been counterbored from underneath so that the normal mounting studs can be used. This means I now need to make 4 extended fixing nuts,which will be 3/8" setscrews with the 1/4" bsf thread tapped into the end and a 22mm x 6mm thick washer between the setscrew and the plinth.

Mike H · Post by **Mike H** » Thu May 07, 2009 5:40 pm

I can smell the machine oil from here...

Aaaahh!

pre65 · Post by **pre65** » Mon May 11, 2009 12:11 pm

As i could not find the 1/4 bsf tap the mounting studs were made from M6 (a little loose fit !)and a lock nut was used to stop them going too far up. This necessitated a small counterbore in the plinth top to clear the nuts. The base is now firmly mounted to the plinth with three mounts as per the picture and one slightly different because of the close proximity of one mounting.

http://i111.photobucket.com/albums/n146 ... erbolt.jpg

The anti vibration mounts are screwed to the plinth base and an M6 rod goes from the centre,through the base board and into the pointy wooden feet which are covered with my special pixie dust varnish. Secret recipe don't you know.

http://i111.photobucket.com/albums/n146 ... unting.jpg

Now to find a cartridge for the "bent" arm.

cressy · Post by **cressy** » Mon May 11, 2009 12:59 pm

i'd gladly pay 12,547,874.46 for 0.0000025g of your pixie dust phil, the benefits will surely be worth it!

pre65 · Post by **pre65** » Mon May 11, 2009 4:02 pm

Indeed ! To be fair,I don't get the "pixie dust" first hand. One of the asylum nurses gets it for me and only charges £100 per qtr gm.

Mike H · Post by **Mike H** » Mon May 11, 2009 6:24 pm

audio-talk

401 Plinth

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