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TW Raven Owners: Set Up Questions

Through the magic of sweet talk, I turned my Orbe into a Raven and mounted my Graham 2.2/Benz LP.
I am looking for a isolation base for the Raven. I have a 1 3/8" piece of granite coming soon so I can ditch the MDF I use now (a temp. meas.!) Symposium, SRA, HRS, etc., can anyone share their experiences with isolation bases? I saw the thread about loosening the Stillpoints.
Initially I had an issue with using the rough side of belt. The belt shimmied up/down on the pulley at a specific spot on belt. Also, the speed fluctuated and I could never get it dialed in with the PSU. So, I went to the smooth side of the belt and then raising the back side of the motor (unscrewing one of the isolation feet) slightly moving the belt down from "center" on the pulley. This moved me from 33.2 to 33.3 and I have no more belt shimmying and the speed is rock solid.
I'd appreciate any tips/tricks etc.
gerardff
peterayer
1,382 posts
 
Suteetat, I can't answer that. And I'm not sure you will ever get your floor to flex. I'm just saying that Halcro is describing a type of pre-stressed concrete slab and it will not behave like a standard concrete slab located on the ground. You may not have any issues at all.

However, if you can borrow a Vibraplane or other serious isolation platform for you unsuspended turntable, you should hear quite an improvement in information retrieval or resolution.
suteetat
435 posts
 
I agree that something like vibraplane is something that I would like to try. Unfortunately there is nothing locally similar available so I think I will have to wait until I know for sure what I will do with my tw regarding motor option before I will invest in vibraplane or minus k. In the meantime I probably will try symposium since I can use it with other equipments later and thy are not so expensive.
halcro's avatar
halcro
2,664 posts
 
30cm is quite thick for a concrete slab.....especially a prestressed one. How do you know this fact?
The load carrying capacity of any floor has little to do with with it's BEHAVIOR under dead loads, live loads and impact loads. 400 Kg/m2 is not so great considering that 4 hefty men each weighing 100Kg can stand on a floor area not much more than this?
A trampoline can certainly support this load also but I would be loathe to locate my turntable on one?
suteetat
435 posts
 
I checked with my building engineer who has the building construction
blueprint and that's what he told me, regarding 30cm thickness. I don't
really know building specification and don't know what is considered norm
and standard of high rise elsewhere but overhere 400 kg/m2 is the
standard as far as I know.

Also my next door neighbor bought a unit below him and managed to find a
small space to drill a hole for a staircase between the 2 units who also
mentioned that 30cm thick concrete was what he needed to go through as
well.
suteetat
435 posts
 
I just have a lead on Minus-K locally but it probably will be closer to the end of the year before I could try one (just in time for Chrismas, I suppose!). I wonder if something like Minus-K or Vibraplane is good only for non suspended table or also equally good for suspended table like Linn?
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