|Tim Hammond||28/05/2020 12:49:51|
|21 forum posts|
Last evening I watched a video on YouTube posted by Adam Booth (Abom 79 ) where he described and demonstrated a hoist he's just acquired called a "Sky Hook", used to assist in the mounting and demounting of lathe chucks, milling vices &c. on machine tools. It's safe working load is 500 lb, and it was mounted on the toolpost of his Monarch lathe. It occurred to me that this set up imposes a very high load on the toolpost,, enough probably to affect the integrity and accuracy of the machine. Many of the comments posted beneath the video echoed these concerns. Has anyone else seen this video? If so, would they care to share their thoughts?
|Kiwi Bloke||28/05/2020 12:53:20|
|424 forum posts|
I don't want to watch the video - it sounds like a horror movie...
|2500 forum posts|
I’ve just had a quick look and it doesn’t look that clever to me.
|Jed Martens||28/05/2020 13:21:15|
82 forum posts
I watched it last night. I'm very much a novice, and Adam very much is not, but my eyebrows were raised the entire time. He does address the obvious concern, but only by saying that manufacturer assures him it is ok. And also he isn't taking it anywhere near the 500lb maximum load.
My thoughts were to find some other method of mounting it to the lathe and mill. It looks super-useful for those large chucks and vices. But clamped into a tool holder with a couple of set screws?
|David Colwill||28/05/2020 13:56:11|
|633 forum posts|
I saw this too and didn't like the idea of 500lbs hanging off my toolpost but having thought about it, I'm sure it is okay.
If you want something to compare, have a look at how the ram is held on a cheap 1000kg engine crane. The materials on these are cream cheese painted to look like cast iron. He has this mounted to a quality toolpost on a 17" Monarch lathe. I would say that most lathes could lift the weight of the chucks that would be used with them from the toolpost without too much bother.
Sadly though his channel has just turned into a series of paid endorsements ( at least that is how it seems to me ) and it is difficult to gauge how useful any of these things are!
|Clive Foster||28/05/2020 14:02:36|
|2200 forum posts|
I imagine that the stress is actually fine. Real world things tend to be much stronger than you think when properly installed and undamaged.
Allegedly you can lift a grand piano via one high tensile 6 mm bolt! Don't care who did the calculations I'm not standing underneath!
Doesn't seem to be any UK representation.
I guess they are basically a chain over a sprocket, with suitable keeper guides, system driven by a geared winch and brake.
Personally I think the work cart mounted variants are a better idea **LINK** but I have more room to manoeuvre than many folk.
|Martin Connelly||28/05/2020 14:13:08|
1364 forum posts
M6 eye bolt max load for a standard one (BS4278) is 100kg, axial, not at an angle.. That must be a baby grand piano. It's not the metal in the core that matters, it is the thread that will get stripped by excess loading.
|Jeff Dayman||28/05/2020 14:28:33|
|1817 forum posts|
The sky hook hoist idea is not new. The biggest disadvantage is the reach is limited, the hoist itself must be manhandled into position and back off the job, and it is right in the way of many lifting ops. Much better to install an overhead crane or jib of some kind, ceiling or wall mounted, even if it is light capacity. Various ones have been shown in ME over the years.
On a big heavily built lathe like Abom's Monarch I would not worry too much about the strength of the toolpost. On lighter built hobby lathes it would not be advisable.
As far as the endorsement aspect of the Abom channel I think it is an economic reality that he has to do endorsements to make ends meet. A one man general purpose machine shop in the US has limited potential for income. He is also a tool collector, particularly of tool types no longer used in industry due to faster / more efficient / cost effective tools being developed in industry. This type of collection is costly and unlikely to generate profit from usage. Also there are fewer and fewer companies doing general repairs as he does due to the high costs. One recent video involved a multi-hour shaper and mill setup / ops to dress gasket surfaces flat on a Chinese imported intake manifold for a Ford Mustang. This manifold was not fit for purpose as supplied, but was cheap to buy. Time was spent installing it, finding gasket leaks, then removing it for repairs. If the total cost of the install/ fault detect / remove/ repair by ABom was compared to the purchase and install cost of a high quality manifold from a US supplier like Edelbrock I expect the Edelbrock manifold would be far less money overall, and it will work perfectly right out of the box, from my experience. I would not participate in the money loss cycle of using Chinese high performance car parts. But it does make good youtube "reality" TV.
Edited By Jeff Dayman on 28/05/2020 14:30:07
|Cabinet Enforcer||28/05/2020 21:20:16|
|72 forum posts|
My thoughts are that it would be impossible to sell this product in Europe (including here), it is clearly intended for regular installation, it's safety relies on the operator correctly comissioning it on every occasion it's installed (assuming it's properly engineered in the first place), and our system of law has frowned on that sort of thing for a very long time.
I think it probably highlights one of the biggest differences in culture between us and the yanks, everyone is responsible for their own safety over there, this attitude tends to engender solutions which protect an individual rather than protecting all.
|Alan Waddington 2||28/05/2020 21:58:35|
|501 forum posts|
Nothing on my lathe that i can’t physically manage at the present time. But that would be a useful addition to the mill.
last time i used the dividing head it was touch and go if i could lift the bugger on to the table, took 3 attempts and nearly did myself a mischief.
Felt stupidly dangerous and reckon it won’t be long before i simply can’t do it.
|duncan webster||28/05/2020 22:07:50|
2584 forum posts
If you work it out, a 10ba grade 8.8 bolt (if there was such a thing) would not exceed its proof stress on the core diameter when lifting me in direct tension. Would I get in a lift held up by a single 10ba bolt, not on your nellie! I'd want at least 4 off M10
My chucks are manageable, but I've got a runway beam made of unistrut and a little chainblock to lift heavy stuff off the floor onto the bench
|Clive Foster||28/05/2020 23:04:21|
|2200 forum posts|
I know exactly where Cabinet Enforcer is coming from and, to be honest, I have some sympathy with the European approach. But the men in Brussels do tend towards remarkably selective blindness. You only have to look at the things masquerading as jacks supplied with cars for the last couple of decades and more to consider that there are areas where a bit more applied legislation would be appropriate. The thing supplied with her-ladyships L322 Range Rover (now recently departed thank God) pretty much re-defined inadequate. I'd be worried lifting a pedal car with it. At least my lovely P38 Rangie has a properly strong bottle jack in the back. Admittedly you still have to be careful to ensure it won't tilt but atleast its not going to collapse on you. I'm told the L322 one isn't the worst out there either.
A half decently engineered plug in the side, run up a screw, type always seemed best to me. Lancia did about best of breed for the HPE.
Getting back to the Sky Hook I'd say anyone who couldn't slot that in adequately safely would be dangerous in chage of shoelaces. Realistically the 500 lb load capacity seems far to high for lathe chucks, mill vices, rotary tables et al. 100 or 150 seems more the mark.
When it comes to lathe mounting it needs a T slotted cross slide. These seem to be the norm in the USA but less common in the UK and Europe so less of a potential market.
A work cart mount version is what I'd want as my workshop is too large for Duncans unistrut or similar beam to work sensibly. I'd need about three I think in addition to the two heavy lift crossways RSJs that seemed a good idea when I built it.
A tube bolted to one corner of the work cart with the Sky Hook sat on a similar, slightly smaller one, that could be dropped in when needed ought to work. Worm drive gearbox I think so no need for a brake. Power it from a battery drill via a 10 mm / 3/8 or 1/4 hex spigot shaft. That handwheel would get seriously in the way when storing.
Edited By Clive Foster on 28/05/2020 23:05:22
|Paul Lousick||29/05/2020 00:27:39|
|1405 forum posts|
A lathe that has a 500 lb chuck would be a BIG lathe
|Nigel Graham 2||29/05/2020 02:24:57|
|632 forum posts|
I have not seen them advertised very much but there are davit-type hoists made for precisely this kind of work; and are generally bolted to the floor, with due attention to the floor and fixings of course, behind a lathe or alongside the column of a milling-machine. The hoist itself is usually a chain-block on a runner.
One at my works had such a hoist with a square-section tube boom that contained the runner, with the attachment point hanging though a longitudinal slot. It was used with a chain-block for manipulating the heavy steel lid on a piece of laboratory equipment.
I have just completed the travelling beam on an overhead hoist I am building for tasks such as handling heavy machine-tool fittings, and designed to make best use of the limited headroom in my workshop. I have still to build the crab but can use the crane otherwise to a some extent already, and in fact was doing only a few hours ago.
|jimmy b||29/05/2020 03:39:52|
635 forum posts
I think that it would be fine 1 1/4" shank tooling could generate a hell of twisting force. The loading is not a "shock" load either.
|David Colwill||29/05/2020 06:30:47|
|633 forum posts|
I'm getting to this stage too. I like the concept but am not keen on the toolpost mounting, not because I don't think it isn't strong enough but because it seems a pain especially as it has to be changed over depending on which machine you are working on.
My DSG and mill are next to each other so I think some sort of swinging arm between the two is the way I will go.
|Cabinet Enforcer||30/05/2020 20:43:32|
|72 forum posts|
Apolgies for the selective quote Clive; I wasn't really reffering specifically to the EU approach to lifting equipment, which would prevent toolpost mounting like this for a number of technical (and pretty valid imo) reasons. It was more the latter point you made, it was a couple of hundred years ago when British judges started to decide that employees are "allowed to be stupid" for want of a better phrase, most Europeans seem to be more inclined to the American approach of personal responsibilty than we are in the UK, I think maybe this is down to the breadth and depth of our industrial heritage.
|david gregg 1||30/05/2020 20:53:34|
|9 forum posts|
I would not be in favour of bolting the skyhook onto the tool post a couple of years ago being of an age when lifting heavy weights was becoming a problem I decided to sole the problem I bought some heavy duty door tracking and fastened two lengths each about 15foot long to the underside of the roof trusses each truss is at about 2foot centres I then suspended another length of door tracking from the and on this piece of tracking I have an electric hoist The power cable to the hoist has steel rings tied to it and these slide on a a length of plastic covered steel wire .With this ssystem the hoist can be pulled up and down and across the workshop ,I can use it lift the rotary table on to the milling machine also the 10 inch chuck on to the DSG I can still manage to lift the chucks on to the Harrison 300 .I still repair some large rotors for a friend and without the hoist I could not get them into the DSG ,as you get older you have to get solutions for these problems
|Alistair Robertson 1||30/05/2020 21:31:37|
|90 forum posts|
We had a Colchester 500 which was supplied with a "Skyhook" when it was new. It mounted directly in the Dickson toolpost. It had been used for years with no problem but the safety officer wanted a certificate of suitability or something before he would allow us to continue using it. We contacted the manufacturer in the US and they returned a very impressive document folder with full certification for use on the Clausing version of the 600 group lathe complete with CE certification for use on european supplied machines. The safety officer deferred to the weight of paperwork! Ironically we never used it again as the lathe was moved to an area covered by an overhead crane.
|John Reese||30/05/2020 23:21:38|
|842 forum posts|
I have an old Sky Hook. I use it occasionally to put the vise or rotary table on or off the mill. It is inconvenient to set up. I had considered using it on the lathe to handle the 60 lb. chucks. It seemed like too much bother to lift the hoist into position every time I needed to change a chuck. I had a jib crane that mounts to the receiver for the trailer hitch.
I made a pedestal for it that is anchored to the floor. It handles the chucks quite nicely.
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