Meade Wedge upgrade part 2

[steelfixer]

I finally got a break from the drudgery of the normal day to day stuff so I set about doing the bush conversion on this wedge.

I started by measuring each hole for diameter and depth and then machining up each bush separately to suit.

I have allowed a 4mm wide step up in diameter to use as a thrust face.

After a couple of hours I was ready to start on the pivot bars.

I began with the lower pivot bar and machined each end of it to suit its permanant home position.

In doing this process I also allowed for a 2mm offset to carry the thrust washer.

This thrust washer has a 2 degree taper on one face to allow some 'give' when tightening the frame up and for an easy lubrication point..

I then set about the top pivot bar.

Again each end was machined to fit each bush.

I also allowed for the bushes to protude through the top plate by 1mm each side to act as a thrust bearing against the inside face of the frame.

I then put the ALT adjusting bolt back in place to test the wedge for play.

Result - You have a smooth transition from one end of the ALT scale to the other.

The only detectable play is at the top end (65 degrees) and I would guestimate this to be 5 thou of an inch.

This is with all the locking bolts loose and by loose I mean they are so loose you can spin the washers round on them.

Next item on the list is to see if I can do something with the lower pivot bar where the ALT adjusting bolt goes through it.

Thanks

Graham.

[Merlin66]

You may have to dowel the side plates to ensure they are square to the tilt plate....the alignment will need to be maintained....

When you tighten up the clamp screws is there any measurable movement (lateral or twist).......

[steelfixer]

Hi Merlin.

No none at all.

I have made the tollerences in the bar to bush very close.

Having said that dowling it now it is all in place with some stainless steel dowls sounds like a very good idea.

I took on board what you said last night about keeping the side plates adjusted as close to the top plate as possible.

Hence the reason for the protruding bushes.

I went about it from a different angle.

I moved the side plates out as far as they would go against thier mounting bolts and then worked in from there.

Now the only way the side plates can move or flex is inwards.

The other unexpected benifit this has produced is because the bushes are rubbing on the inner face of the side plates you will only need to gently lock one side to tighten both. I hope that makes sense.

Any way it has certainly stopped all the play.

Have you made any mods on the assembly in the center of the AZ adjuster.

I have here this tiny flimsy bracket with a slot in it.

I presume this bracket fixes to the top of the pier to allow for the AZ adjustment.

Surely with the weight of something like your scope on the top this cannot be strong enough.

thanks

Graham

[Merlin66]

With the three clamping screws "just" loose and the centre bolt tight ( a slight smear of grease under the wedge bottom plate..... the Az seems to work pretty well; the weight of the scope and mount basically keep the wedge "clamped" to the top of the tripod and the slop in the mounting bracket on the tripod edge is no big deal - it moves the wedge when you want it to move......

Then clamp the wedge with the three bolts....

[steelfixer]

Thanks Merlin.

Having never used or in fact seen a wedge in use they are a bit of a mystery to me.

I take it the fork mount on your scope provides the tracking caperbilities then.

[Merlin66]

Yes,

The Lx200 fork and drive base, all 15Kg of it sit bolted tightly to the tilt plate on the wedge....that gives the polar alignment......

[steelfixer]

Merlin have you got a photo of this beast of yours I would love to see it.

[Merlin66]

These don't show the subsequent addition of the guide scope or the spectroscope.....

The 12" OTA as I said weighs in at 17.1Kg and the fork base at just over 15Kg.

The wedge sits on a "reduced hight" - 8" cut of the legs! HD tripod.

HTH

[steelfixer]

Merlin I am seriously impressed.

That is one hell of a setup.

How on earth do you fit that on your own.

I think it would scare me ridgid trying in case I dropped it.

[Merlin66]

Yea....you only try lifting the scope/mount onto the wedge once....then you use a second willing body to help!

I take the weight, and my wife "guides" the top mount bolt into the notch in the tilt plate..after than you can relax.....

[Merlin66]

Just re-visiting the thread on the Wedge rebuild....

What was the final outcome?

Better and/or more accurate Alt/Az control??

[steelfixer]

Hi Merlin.

Sorry for the late response I have only just seen your post.

The outcome is yet to be decided. The Wedge is still sitting in my workshop as its owner want me to build a pier top conversion plate for him.

He is still awaiting the delivery of his pier so he can send me the dimensions for fixing it.

Time will tell.

[Merlin66]

Any news on the benefits of this upgrade mod?

Did it make any real difference?

[Rols]

Nearly 12 months after the upgrade and a few issues later with the scope, yes it was certainly worth the effort, the scope alighns beautifully as Graham suggested it would 'very' smoothly.

The upgrades removed near all slop when losening to fine alighn, i'v spent hours with this setup now and althought perfect alignment seems to be a thing of much fine tuning i am very satisfied with the ease and accuracy that i have achieved. I think without the modifications i would have been doing a lot more work in the dark hours. i'm glad Graham was able to make a sloppy Meade wedge a Super wedge, Thankyou Graham for finding the time to help me, thankyou also for the generosity you showed in delivering and helping place it, it's an old school attitude that you would help someone because you can, and a selfless attitude that you would have done all this without want for money or praise but you certainly deserve some praise.

anyone with a Meade wedge that seems to be over tight, sloppy when lose or wrong again when tightened, would do well to take a look at what Graham did and see if they can find a willing party to help them get things how they should have been from new.