@gunrunnerjohn posted:

Send me an email, and I may be able to help you with the parts.  I know I have the switches with the long arm, and I got the spring loaded pulley from Tim at Mianne, so maybe you can get one from him as well.

Thanks again, John. This just might work out with the long arm micro switch for the lower limit switch. Slight downside is that it means wiring the micro switch on the opposite side of the walk through.

I need to get my router bits sharpened.

Control wiring is complete and the yellow remote is gone. The cable to the remote has been re-wired to bring common, neutral, and the two motor leads over to the 4x4x4" box.

I was intending to use a plug-in usb charger for 5 vdc power to the relays but I happened upon an ancient satellite radio wall wart. After cutting it open I was so impressed with it's looks it just had to go in the box. Plus it fit along side the motor cap. You can see the two relays occupying the balcony section.

My intent was to hot glue the boards down but I had to remove the psu a few times to fix the wiring so I just left the glue out. I did cut a piece of 1/4" plywood to keep the parts separated.

The two enable lines and a ground were extended to the outside of the box for easier wiring and it also gives access to control the hoist with a jumper wire if needed. No voltage in any of the control wires, just a circuitous path to ground.

I received the micro switches from @gunrunnerjohn and he is correct that these switches make setting the limits much easier and seem to be very repeatable.

Here is the upper limit switch mounted to the upper stretcher of the hoist-side table, wired normally closed. A small block of plywood was attached to the lower stretcher of the rising table and that makes contact with the switch lever in the up position. I am getting a consistent 64 3/4" table rise.

And now the most worrisome limit, the down position. I worry no more, it worked out so well with the cable spring and sliding bolt. The bolt is pulled to the limit in the slot before the table can rise, and the table is fully seated before the bolt is released. It worked the first time and I haven't had reason to touch it yet. This switch is wired normally open.

Up

Down

And last, one of the toggle switches mounted to the table leg. One on each side of the table. These may move in the future depending on how the rest of the benchwork turns out.

Looks good, and sensing the cable slack seemed to be to be the foolproof way to insure the table was down and seated before the limit tripped.

That long lever really helps as well. There is still at least 1/4" of play on both limit switches when they are in the tripped position, so there's no binding or crushing worries. And to think at one time I was considering unwinding the cable and removing the spring. I would still like to replace the cable, it sounds like grinding gears, but I don't want to lose the spring.

The flex in the long lever really helps to avoid things getting bent out of shape at the limits.  FWIW, the winch that comes with the Mianne benchwork is pretty noisy, but I've learned to live with it.

I don't understand replacing the cable, is it getting damaged?

I don't think there is any damage and this particular grinding sound only happens when the cable is pulled tight and is lifting, not on the way down. I think most of this noise is due to the cable not staying nicely on the reel. You probably observed the same issue when the cable gets too slack and unwinds a loop or three. It is necessary to disassemble the middle to be able to carry things through the doorway so I expect the cable to need some adjusting again. Once set in place I'll see about attempting to rewind the cable.

Listening this morning the noise is much less than it was now that the limit switches and spring are providing a little more tension control. Still the wrap loosens enough that the wrap below protrudes into the wrap above. When the cable tightens there is some cable dragging back into place on the reel. Also, each time the cable jumps across a previous wrap.

The cable mess.

Once I got my Mianne lift bridge adjusted, there is no issue with cable slack.  I think your tangle of cable is because you have too much cable on the reel.  When the bridge is down and you're seated, there should only be a couple of turns of cable left.  My cable is never slack at any point in the travel, that was the whole point of the spring loaded switch.

Here's what my cable spool on the winch looks like down and up.

Bridge Down and Seated

Bridge Fully Up

Ok, the cable is cut down so there are about 3 coils of cable on the reel in the down position, now wishing I had done this before. Easier to deal, no more noises, and some of those extraneous parts are gone.

Lookin' good, and an improvement in function is always nice too!

Thanks for the tips, John!  I believe it is done.

Two things I would do differently. First, the side tables can be wider. 18" wide would be easier to work with. Second, the hoist needed to be mounted more securely and was lowered to avoid rubbing the plywood decking due to slight flexing during the lift.

The Mianne side tables are only 12" wide, however the winch is mounted on a 3/4" plywood board, and there's no flexing of anything under there during operation.  The one place I see flexing is on the bottom of the moveable bridge section where the pulley redirects the cable up and under the bridge.

I don't know the specifics of how Mianne mounts the hoist but I ended up sort of doing the same. Before adding this plywood mount and all four mount bolts, the hoist was only secured by two bolts through holes in the stretcher. The flex was due to the steel hoist mount pivoting on just two bolts. I under estimated how much tension there would be. When I laid a straight edge across the top of the stretchers the hoist cleared, but when lifted, it would come up 1/8". I can image the noise that would make once the plywood surface is added. There are cross members between the upper stretchers on either side of the hoist mount on both end tables so the upper stretchers can't flex.

When the table is up I see the lower stretcher of the lift table flex toward the pulley on the hoist-side table where the upper limit switch is located.

This is my acceptable looking compromise for attaching the hoist. No more hoist movement. Had I planned better this could have been cut from one piece as part of the stretcher. Ideally, the hoist would have been mounted about 1/2" or so below the surface plywood.

Mianne mounts the winch on a horizontal piece of 3/4" plywood in one of the side structures.

@turkey_hollow_rr posted:

When the table is up I see the lower stretcher of the lift table flex toward the pulley on the hoist-side table where the upper limit switch is located.

That's exactly what happens with the Mianne design as well, and it looks like yours has the same design.  I suppose it's fine, the bridge hasn't collapsed yet for me.

Due to the fact that any of us have a serious reduction of follicle based scalp protection I would suggest something to consider would be adding some premium 3/4" hot water pipe insulation with a lengthwise slit  to the bottom edges of the lift framework.

A round over router bit could also be helpful.

The pipe insulation on mine has saved my scalp a number of times!

I have to admit I have already whacked my head on the corners of the two middle cross supports a couple of times. I haven't learned to keep my head down ALL THE WAY across.

The pipe insulation is a good solution. We have some around here that is pre-split. I'm thinking about 1/8" hard board bent along the curve of the arches for a ceiling when the table is up but there are still two outside edges waiting to scalp me.

Those went on right after the second divot out of my scalp!

For a better view here are the hockey pucks I make for the Monaco swivel levelors when used over carpet.  They are a 3 1/2 X 3/4" plywood disk with a recessed inset for the adjustable base.

On the bottom of the disk I fasten a 3 1/2" round disk cut out of plastic office chair protector with the plastic nipples which are set into the carpet nap.  This makes for secure positioning.

With the legs firmly embedded in the carpet and fastened to both the cross members and longitudinal stringers,  a free standing peninsula can be held steady.

Typical installation

@Tom Tee posted:

For a better view here are the hockey pucks I make for the Monaco swivel levelors when used over carpet.  They are a 3 1/2 X 3/4" plywood disk with a recessed inset for the adjustable base.

Tom,

That's the smallest circle I can mill with my bandsaw, a 1" Forstner bit works great. Somewhere I have a router jig for circles but I'm not sure it gets to 3".  Anyway, I can clean this up on the disc sander and use a thinner bandsaw blade.

My bench work will be very similar in style to your picture but simpler, basically a 10 x 22 with an aisle down the middle. I have 3 bridges to work in so there will be a few sections that drop lower for future scenic work similar to what I see in your picture.