Layout table surface levelingi

I would use plaster of paris. Much easier to sand with the same result.

Have you considered replacing the plywood in that area with a better grade of plywood?

Here's an idea:

Put the turntable on to a separate piece of 5/8" plywood (called a platen),   UNDER the table, with the turntable mounted in a hole cut in the platen.

Drill clearance holes in each of the four corners of the platen and the table top.  Epoxy 4  X #8 hex nuts AND flat washers in place underneath the table and through the platen.  Insert machine screws through the platen with washers and hex nuts glued to the platen as well. Then your machine screws can be turned to lift and level the whole assembly as needed.

And- by the way, the proof strength (the point at which the fastener is stretched and subject to long-term failure) of #8-32 low-grade (2) machine screws is 462 lbs./ screw.  A safe factor is 80% of proof strength, so 4 X .8 X 462 would mean that the four screws should be safe at over 1400 lbs. total weight of turntable, platen, track, and locomotives.

Then figure a way to disguise the seam, or just fill it in- there should be no changes over time, assuming a good grade of plywood, relatively dry conditions to avoid warping, and no changes in the table top itself.  You might actually want to frame the area around the turntable underneath to make it rigid.

Get a good grade of 3/4" plywood.  Cut to fit the area(s) underneath your current plywood table top, then screw down through your existing plywood table and pull your new plywood piece(s) up tight to the bottom side of your existing table.

OR, do basically the same thing using 1 x 3 or 1 x 4 joists in place of the new plywood.  The ends of the joists don't even necessarily have to be attached to any existing framing, as all they're doing is pulling the warp out of your current table top.

Lastly, go ahead and use some sort of leveling compound.  Should take a whole lot less (if any at all ).

Hope this helps. 

You could also try a pack of pre-cut wood shims, available at the big box hardware stores.

gunrunnerjohn posted:

Have you considered replacing the plywood in that area with a better grade of plywood?

Not a viable solution for me, as the layout is about 90% complete.  I purchased 8 4X8 sheets of 5/8” plywood with either a birch or oak surface 14 years ago - can’t remember which since I painted the entire surface green before beginning the layout.  The plywood is supported by 1”X4”s spaced 18” apart.  The structure is/was strong enough to support my weight without any sagging.

Appreciate your response.

Mike Wyatt posted:

Here's an idea:

Put the turntable on to a separate piece of 5/8" plywood (called a platen),   UNDER the table, with the turntable mounted in a hole cut in the platen.

Drill clearance holes in each of the four corners of the platen and the table top.  Epoxy 4  X #8 hex nuts AND flat washers in place underneath the table and through the platen.  Insert machine screws through the platen with washers and hex nuts glued to the platen as well. Then your machine screws can be turned to lift and level the whole assembly as needed.

And- by the way, the proof strength (the point at which the fastener is stretched and subject to long-term failure) of #8-32 low-grade (2) machine screws is 462 lbs./ screw.  A safe factor is 80% of proof strength, so 4 X .8 X 462 would mean that the four screws should be safe at over 1400 lbs. total weight of turntable, platen, track, and locomotives.

Then figure a way to disguise the seam, or just fill it in- there should be no changes over time, assuming a good grade of plywood, relatively dry conditions to avoid warping, and no changes in the table top itself.  You might actually want to frame the area around the turntable underneath to make it rigid.

Mike,

Sounds like a good option if it were not for the fact that one of my 1X4 support beams passes directly under where the TT must fit.  Also, a gange of about 50 wires pass under that.

Thanks

BILL HUDSON posted:

Mike,

Sounds like a good option if it were not for the fact that one of my 1X4 support beams passes directly under where the TT must fit.  Also, a gange of about 50 wires pass under that.

Thanks

Perhaps your 1 x 4 support beams are not perfectly straight and true where you plan on mounting your turntable.  If so, any chance of removing them and replacing them?  Or simply attaching new straight joists along side the existing beams?

banjoflyer posted:

Use a deck of cards to raise up any low spots.

The average card is about 0.2 mm thick (less than 1/100 inch)

That should give you very fine adjustment of the Turntable height where needed.

When you are satisfied with the result secure the cards to the table top or the turntable base with glue.

 

This solution seems the easiest and least disruptive so far.  My wife has squirreled away a deck of plastic cards she will never use.

Thanks

Or, consider not using a flat surface mount plastic TT. 

Achieving a flat installation is only the first of other issues possible down the road. 

If you go ahead in using a flat plastic TT,  first set the TT on a large piece of glass to see how flat the TT really  is.  I have installed quite a few TTs and even with a good non plastic drop in TT,  runout can be a concern.

If you start shimming voids are you sure which surface is warped?  Is it the plastic base or the mounting surface?  Or both?

If it is the plastic TT base which has the deflection and you shim the installation to maintain the warped base you are assuring that the TT base will never assume the designed position intended.  Possible drive problems depending on severity. 

Also,  There is a difference between flat and level.  You are seeking a flat interface.

Note;

Level-lastic is NOT a self leveling product.  It is to be used to flatten an irregular surface much like a skim coat.  It is an excellent product  for providing a flat surface.

There are self leveling products which must be poured on to a dammed surface and allowed to set up.  much like pouring water within a perimeter restraint to make an ice skating rink in your back yard. 

It must go on with a minimum thickness of 1/2" in order for the ebb and flow to work it's self LEVELING action.  We used self leveling mixes with slopped flooring.  It provides a glass flat and level surface.

Self leveling products are expensive and are frequently installed incorrectly because contractors try to cut the cost by going thin and failing to achieve the desired surface.

Bill, there's a product on the market named "LeveLastic" that I've seen builders and / or flooring contractors use to level off a plywood floor that could have similar issues as you've described before a floor covering is installed. I've never used the product personally, but it appears to act as a leveling agent for high and low spots.  Without seeing your issue with the plywood, it's hard to tell if this would work for you.  I just searched it and Home Depot stocks it.  Good luck!

Rather than using the deck of plastic cards your wife has squirreled away, you can get a whole, brand new, set of cards at Dollar Tree for $1.

A few pictures of the installation of a (used) Diamond Scale TT on my layout  Frame work/support level.  Good grade of MDO.  Medium density overlay board.  Framework level, and a good grade of surface material.  not a lot of need for additional adjustment. IMO.   

phrankenstign posted:

Rather than using the deck of plastic cards your wife has squirreled away, you can get a whole, brand new, set of cards at Dollar Tree for $1.

Wife says o.k.  She has a tablet to play multiple solitaire games in short period of time.

phrankenstign posted:

Rather than using the deck of plastic cards your wife has squirreled away, you can get a whole, brand new, set of cards at Dollar Tree for $1.

Mike CT posted:

A few pictures of the installation of a (used) Diamond Scale TT on my layout  Frame work/support level.  Good grade of MDO.  Medium density overlay board.  Framework level, and a good grade of surface material.  not a lot of need for additional adjustment. IMO.   

Mike,

Looks like you have a nice TT/RH setup.  I gave up on installing my Korber 3-stall unit - not enough space to get a track match between the TT and the three RH doors.  I only have 6” to spare between TT and middle RH door.  I Am going with three engine houses.  I can angle each one to aline with the TT.

As far as the flat table top subject goes, I put a straight edge on the surface and could not see any daylight, even using a flashlight.  But when I placed the TT there, a few spaces could be observed between the TT frame and the table top.  However, there appears to be uniform spacing all around the platter between it and the frame.  So I am going to use the card test, assuming the table is the issue.  No harm trying that first.

Bill

I level uneven parts of my layout with sugar packets, then I don't need to model the giant ants, they just come on their own.

Chris S.

Bill,

you may want to use flex track for the spurs off the turntable, it makes aligning to the roundhouse much easier especially with limited space.

Rich,

My problem is I have a number of engines that require minimum O72 track.  I could not get that size curve in the short space between TT and RH.  Got two out of three but could not make the third one work.

Impacting my space is an access hatch.  Without that the RH would fit.  However, I must have that hatch.

I have got a workable solution using 3 engine houses.  Thus, I have come to accept that I will not have a RH on my layout.

Regards

Bill

FireOne posted:

I level uneven parts of my layout with sugar packets, then I don't need to model the giant ants, they just come on their own.

Chris S.

Chris,

Sounds like a plan.  Wonder if the ants could be trained to rotate the TT.  If so, the motor could be held in reserve in case of a union strike😊.

I had done an access hatch, another part of the layout, that has a building on it. 

Mike CT posted:

I had done an access hatch, another part of the layout, that has a building on it. 

 

I have two access hatches, but they are nowhere near as perfectly fitted as yours appears to be from the picture.

Nive work.

BILL HUDSON posted:

Rich,

My problem is I have a number of engines that require minimum O72 track.  I could not get that size curve in the short space between TT and RH.  Got two out of three but could not make the third one work.

Impacting my space is an access hatch.  Without that the RH would fit.  However, I must have that hatch.

I have got a workable solution using 3 engine houses.  Thus, I have come to accept that I will not have a RH on my layout.

Regards

Bill

 

I missed the fact that the Atlas turntable is so small in diameter - 24" - and would cause overly tight curves.  I used the flextrack with Korber roundhouse's in a number of cases located closely to the turntable, but it was one with a much larger diameter 32"-36".

The Korber Roundhouse was designed for a 32" Bowser TT.  30" at the least.   This is how a 28" Diamond Scale TT matches to a four stall Korber house.   Note:  The center of the left bay is the large space between the windows.  Track is pushed off center, in the house, toward the outside wall/left, but is still in line with the  TT bridge.  (5) of (6) spurs would be impossible without a curve adjustment in the track.     The one outside spur has the curve.    (2nd picture).   Distance between the edge of the TT and the edge of the house, 9" to 12" with the 15 degree Korber stalls.