When delicate stuff has to be done with something HEAVY ?

[graham-xrf]

The phrase is so concise - "put the inked surface against the work". For much of what we do, it's put the work down onto the inked surface plate, but when one has to manhandle a straight-edge reference surface onto the ways of a lathe bed, and it weighs 40kg+ (near 88lb), we have to contrive some kind of hoist or suspension jig. You can't reasonably just have it swinging about on a car engine hoist just any old way. One needs to be able to lift and tilt it exactly right, and lower onto the work spotting surface, make the print, and lift off without smearing.

I can only (just about), dead lift it (a bit). Moving it about at all will strain a valve within (me) somewheres, and to carefully place it it to take good measurements is just not going to happen without a lift jig.

Suggestions from the experienced are sought..

 

[macardoso]

What about a pair of chain hoists on the ceiling? One lifts it from a cart, then hook it to a second one over the lathe? Tighten up on the one over the lathe as you ease off on the one over the cart. You eventually have your straightede over the lathe suspended.

If you took a bit of time I bet you could add an eyebolt and some counterweights at each end so the straightedge is balanced about the eyebolt. That would make it relatively easy to align it with the ways as you lower it down.

Just one thought.

 

[Downunder Bob]

You could try suspending it from your hoist on some stout bungy cords, or springs such that it has an effective weight at the job face of maybe only 1Kg. It would then be easy to manouvre it around without popping any safety valves.

 

[woodchucker]

I vote for a gambrel type (block and tackle) setup . And if you look around you can also find easy locking setups so you can one hand lock the rope, then unlock it.
but the rope setup with pulleys, is far more easy to control.. and no chains to damage your straight edge.
if you think about it, the engine hoist is a perfect place to mount it, but probably not high enough. you could build an insert into the end to raise it for this task. something in a sought of Z shape. but the long leg not leaning but perpendicular to the short legs.

 

[jmkasunich]

Couple of sturdy pulleys attached to ceiling joists. Rope from straightedge up to first pulley, over to second pulley, down to counterweight that is roughly the same weight as the straightedge...

 

[rabler]

Limited space may make it impractical, but if I planned to do a lot of printing with it, I'd want rig on overhead bar with a counterweight. That way you could still manually manipulate the straight edge, but maybe at a 10-20 lb net positive weight. Then you'd have no need to mess with a pulley while trying to also align/print.

Take about a 5 foot bar, suspend it by a rope/chain at the midpoint, drop a line from one end to the straight edge, and hang counterweight off the other. It should pivot enough to give you some range of motion, so you can print and then move it back to a resting position completely by hand.

 

[C-Bag]

Hopefully Richard King will be along because there has to be some kind of acceptable rigging for this. I’ve seen huge camelbacks on eBay and the guy who sold me my Biax had a 6’ one. So even though us hobby guys don’t often do it I know the guys who did this for a living back in the day did it all the time.

 

[graham-xrf]

Thank you all for the suggestions. I think I try something that combines these practical ideas.

From @jmkasunich and @macardoso, I will try and exploit the joists. Over my little shop, where the granite will eventually live, I did make them strong enough to be floor joists, and they are on 400mm centres, and I can use a cross-beam to share load.

From @woodchucker, the suggestion for fine control from block-and-tackle I do like. The manual block and tackles, with chains, are gorgeously slow, and can't run back from being self-driven, and the rope-only version seems more appropriate. Chains slinging about around such surfaces is not a good idea. I will prefer something that is inherently safe if one "lets go".

@Downunder Bob Bungees is so very Oz! It sounds as if it could be useful, but perhaps set to -1Kg instead of +1Kg, so that it does not have to be "held down".

@rabler : Making the whole thing neutral by counterweight, yet able to move it about, is the best thing. Up or down, it stays put. Even though my outside shp, when I move stuff into it, could one day have a couple of steels along it's sides, and a 3.6m RSJ little gantry crane thing, setting up in one corner from joists with a counterweight jig looks to be on.

You guys are the best!

 

[jwmay]

Spring balancer mounted to an arm with two joints. Although, you've got plans now, so maybe nevermind. Lol

 

[graham-xrf]

Hopefully Richard King will be along because there has to be some kind of acceptable rigging for this. I’ve seen huge camelbacks on eBay and the guy who sold me my Biax had a 6’ one. So even though us hobby guys don’t often do it I know the guys who did this for a living back in the day did it all the time.

Funny you should say that! There is a huge pile of good scraping info on the "other" site, among it the sentiment that scraping is now the more and more a skill kept alive by "hobbyists". The pro's just junk the amortized machine, and look forward to the new latest and greatest. There are good folk there too, but sadly, it did not take long to come across unpleasantness.