I think I am going to attempt to make turntatbles

First off let me say I am not new to the audio realm. I am a computer engineer and yes I realize that deals in ones and zeros. However, I have made a few custom guitars. I know a master woodworker and a talented machinist. I have been searching for that perfect table for years whilst living in mediocrity. Well, I have the resources; why not make one from scratch. More than likely I am going to attempt a belt drive unit at first using an off the shelf arm... More than likely an SME. I am working on the power supply circuitry right now as my piece. Any one have any tips... I am thinking solid, large mdf plinth with an attached copper mat and either a heavy plinth with an acoustically decoupled motor or completely detached. Thoughts?
Kudos for the attempt. Keep us posted on how it progresses. The ability you have starting from scratch is a blank slate. Play with it.
Well I will probably start with a plinth and the guts out of my fisher direct driver first to be honest... Then I will move onward and upward... This being my first attempt... I suppose I will teach myself some design 101 on the cheap using what I got first... Once I can get that good sounding I will progress.. I have alot to learn and this ought to be fun at the very least.
You may find some of the resources at The Analog Dept useful here: http://www.theanalogdept.com/index.html

This page from the above website is focused on building various plinths that may be useful as well since that is where you are starting out: http://www.theanalogdept.com/plinth_builders_gallery.htm

Hope this helps.
Find an existing small niche manufacturer wanting to sell. He will already have a small customer base along with some needed tools. Learn from his mistakes.
There are essentially 2 schools of thought on TT design. Low mass-high rigidity, and high mass. High mass is probably easier for a DIY'er to handle since there's little additional "tuning" that is required for a low mass design, and therefore is less trial and error prone.

Designing a TT is mostly about resonance control and tight tolerances on some key parts. After that it is about speed stability. I would stongly suggest keeping things as simple as possible to avoid pitfalls that you may not be able to anticipate in your first attempt, such as using a manufactured arm rather than a DIY (unless it is an exceedingly simple design).

Good luck whichever way you go and remember there is more than one way to skin a cat as the variables add up pretty quickly.
That is the way AJ Conti of Basis and several other manufactures started; they didn't like what was on the market and thought they could better. SME got into audio because Alistair Robertson-Aikman [probably misspelled] didn't like the arms available and had his machine shop build one.
I tried and gave up.There is alot more involved than you might think

Buy a VPI Classic 1 , 2 or 3 and be done with it.
Agree with Vernneal. It only make sense if you enjoy the process of designing and building by itself. I do, so I'm having lot of fun along with enjoying the music on the long run; I also have learned great deal about audio. Otherwise, it is not justified economically; lots of excellent second hand TT on the web market.
"It only make sense if you enjoy the process of designing and building by itself"

I'm assuming this is the case, right?
Good initiative!
Through experience, I strongly suggest the following:
* purchase off the shelf platter (many offerings, "Scheu" is one of those) and well -- or tyou can design & machine he latter yourself (a mechanical engineer will help tremendously).
* work on a (electromagnetic) elevation system for the platter -- i.e. a magnetic bearing; get rid of the bearings friction.

Good luck!
I realize it's involved; and that it may not make sense financially... Well that is unless you plan on selling your creation (which we do). This is the start and I realize the wheel could be being reinvented a little bit; But construction has began on the first plinth and I am excited. The first order of business is for me to take the guts of a VERY inferior table and make it sound very much so better. Then they will slowly but surely be swapped out with more custom pieces. This is a learning process... but I learn quickly... hopefully in a few months I will have some results to share.

While that is an awesome idea for the levitating platter, would this not interfere with cartridge pickup? I definitely am going to try this as I have done a many of levitation projects in the past with tesla coils and etc...
Nowdays it is easy to find strong magnets for cheap on web. But,be warned that isolation from strong magnet field is extremely difficult. I have abandoned this idea after messimg around with multiply mu-metal sheet screens; my best attempt reduced the magnet field by 30% - still way to mutch to live with it. Buy at least good magnetometer for check if you wanna take the plunge.
I suggest you start with the platter design. If you can't get this right nothing else matters. Then the bearings.
How about using a thing sheet magnet under the platter and then shield it with aluminum... much like magnetically shielding a transducer? my idea is to use some sort of less powerful magnetic field underneath the platter to levitate it against another magnet point downward... so pole differential... in theory the repelling action should float it... then there would be a layer of shielding and the opposing forces of the magnets with their backs to the vinyl should not create any undue fields... i would just have to fashion a skirt for the bottom of the platter out of aluminum as well... ooh i have an idea... have to go sketch this out in autocad right quick... bbl
I would look for something other than MDF for the plinth. Maybe the ikind of wood musical instruents are made of?
Another catch in repelling magnets idea is a strong side force applied on the magnets and hence on the journal bearing, if any slightest non-concenricity of the two magnet fields exists. Magnet levitation is inherently unstable. Try to bring opposite poles together and you will feel a whole magnitude of this force. One more lesson I've learned about magnetic field isolation: the shield must be of closed contour around magnets with minimum gaps, otherwise isolation is greatly reduced.
Good for you... I applaud your interest. I would caution you to keep this effort as a hobby, and not expect to make boatloads of dollars from it. I talk from experience. If indeed it turns to gold that others are willing to pay for...so much the better. Good luck

Good for you! I wish you the best of luck, and I hope that you have a little fun in the process.

My $.02 worth: designing a shielded MagLev bearing is not for the faint of heart, pocketbook or math skills. If you are seriously looking for an alternative to M2M or jewel bearings I would suggest that you look at air bearings. They are readily available in a variety of configurations and sizes, and are (relatively) low cost from eBay and other sources.
Well I love a challenge and as an engineer I am really proficient in both calculus and physics... I drew out my plans today while I should have been working (ha ha ha). So its going to work something like a speaker does when it moves the voicecoil within the magnet and will have a regulated power supply to the electomagnet... lots of trial and error I presume... Also going to attempt to make this a direct drive idea... (I know I know lots of magnetic fields fighting each other... most have a good shielding plan)... BUT.. This is the kicker... VTA can theoretically be adjusted one of two ways... Raise and lower the arm or the platter... See where I'm going... Electronically adjustable VTA. On the fly!!! Also when the turntable powers of the platter will rest in a groove in the plinth. I'm running with this idea and there are going to be lots of pitfalls; curse words; and hopefully a supreme result... A turntable with 0 resonance except that made by the stylus and what little the direct drive motor makes. Good thing I used to build and play with tesla coils as a kid :D