Bridgeport lifting eye thread query

What is the thread in the 3/4" (?) lifting eye in a bridgeport mill? I have found different statements of "fact" on various internet sites. The mill is from 1986. (It is still in shipping at the moment so I can't get at it to check it or find the S/N in case it has changed over the years. It is not an adcock and shipley although it has lived its life in the Leicester area.

The two options I have seen on the internet are:

3/4" X 10 TPI BSW

3/4" X 10 TPI UNC

When I find out what it is I would like to get a lifting eye. I am based in Bergen Norway and lifting eyes with BSW / UNC will be hard to source. (I am refurbishing my home and all my machines are temporarily unavailable to make one.)

Thanks,

Steve

My manual says 3/4 BSW

My original Bridgeport manual says 3/4" Whitworth, and a 3/4" BSW tap is an easy hand fit. Mind you a 3/4" UNC tap can be screwed in a few turns too.

My manual, and machine, are by Adcock and Shipley, so I'd expect them to use BSW. My guess would be that US built machines used UNC and UK built ones used BSW.

Regards,

Andrew

Standard threaded rod with some sort of bar etc may be more available. If you are too metric in Norway perhaps some enthusiast restoring old military vehicles would have a big enough bolt. Also perhaps a boat yard supporting British fishing boats would have something.

Hi there, Steve,

This one was top of the list when I googled 3/4" BSW eye bolt:

https://www.cromwell.co.uk/TTC6305219F

There were several more potential suppliers. Minimum order values and overseas shipping may be a problem for you, though. Still, it's worth enquiring.

Best regards,

Swarf, Mostly!

My manual also shows an alternative using two strops, one round each end of the ram, thus avoiding the need for a lifting eye.

Andrew

Moved loads of Bridgy's, never use the lifting eye yet and never will.

There is far too much strain on such a small area as to be frightening. As Andrew says strops are by far the safer oprtion.

Two tonne Beaver CNC mill going over the telephone cables.

all,

Many thanks. It seems that as suggested the most likely scenario is that there are 2 standard BSW for UK made and UNC for the US made. I have contacted the place I purchased from to see if they can tell me. NB the cromwell link eyebolt is only rated to 0.32 Ton I need at least 2200Ib plus safety margin.

I was hoping I could go for the eyebolt approach since the use of slings under the ram will result in having to lift it from a slightly higher point. I plan on hiring a crane to get all my machines to the workshop door since my house is built on a hillside (as is almost everything in the Bergen area) and my plot is very steep 1 in 3. Slings for this is no problem. To get into the workshop from ourside I plan on using an engine lifting crane to move them inside and into position. I was thinking the eye bolt would be easiest for this stage. Anyhow plenty more planning and work to do on the workshop before then...

Regards,

Steve

Steve, Even though you will be having a crane and lifting as regards weight will be no problem yout hight problem is easily addressed.

If you rotate the head thru 90 degrees to the left then you can support thia o two blocks on the bed whilst you detach the screws and using the Y axis pull the head off.

Once lowered two decent people canlift this off and put safe.

If you then wind the table back up you can position the two clocks so they lift the ram with the 4 thru bolts removed and the complete ram assembly with turret can be slid onto the bed.

Once strapped into place you can sling from the knee and inside the turret to lift and gain a good foot in hight..

One thing to check as you lower the head is to get someone to support it with you as it goes over centre. It it has any broken teeth on the cast head gear it can crash completely over [ don't as how I know]

Good point though is that the damaged gear can be reused again by drilling a new dowel hole and installing 180 degrees out because the bottom sectionof the gear doesn't see any wear.

Hi Steve

I hope the crane can position the machine on a concrete apron to enable you to roll it into position.

You mention an engine lifting crane to move the mill, if it is the typical Chinese type with the legs that fold up and has a hydraulic jack to lift a hinged arm you may find it problematic. I have one in my workshop and it does come in handy. however the legs get in the way with large objects. You will probably not be able to use it with the arm extended due to the load being too great.

For moving big machines I rely on a set of black 19mm mild steel bars used as rollers under the base plate of my mill and lathe when I need to position them. Make sure they are long enough, mine stick out about 200mm each side of the base plate, Base plates(s) on my toolroom lathe. I use a crowbar with a bent foot to lever the machine up the 20mm or so needed to slip the bar under. you need at least 4 bars (6 is better). You never want less than three bars under the machine at all times properly spaced out, Once I get the bars under the machine you have to keep rotating the set as you move in small steps maybe 100 to 150mm for each move step. My lathe weighs about 3 tons and the mill is similar. They have been moved several times using this method.

I have seen machines rolled on 50mm water pipe, To me the risk of the machine tipping over is too great with thicker rollers. You may wish to protect the floor from the pressure of the rollers and marking. I use some offcuts of 1.6mm mild steel sheet placed on the floor. It will make the rolling easier too.

The bars I used are 19mm plain not deformed concrete reinforcing steel. left over from a period style picket period fence I made for my house some time ago. At the time the steel was a lot less expensive than the same black steel from a steel merchant. It is tougher to machine than free machining steel however the offcuts from that job have made many jobs. Waste not........

Ideally you should have at least one other helper for safety and it will make the job a lot easier. But if you are working alone think safe, then think safe again on every step,

Regards John

Edited By John McNamara on 01/08/2013 17:03:49

You won't be able to move an engine crane with a load on as the wheels are too small. You can only use it to lift the mill onto rollers. A two ton engine crane can lift one end at a time for that. Make sure the big crane places the mill on 4x2 timbers at 90 degrees to the direction you need to move it and put the rollers under these timbers not the mill base direct. In addition if you aren't on pavig slabs or concrete have that lot on boards to give a smooth track bed.

You probably want a 2 ton crane to get the clearance around the base and weight capacity at max extension is half a ton. In fact a crane this size has enough height to lift off the head + ram if you use tight slings. The ram balances the weight to prevent tipping.

Actually a trolley jack is more use for lifting the base onto rollers if you modify it taking off the wheels and getting a piece of 1x1/2 inch steel that gets under the base. Hard to explain but try it and you will see what to do.

.

??????????

Someone better tell my engine crange that then, better still no don't because whilst it doesn't know it works fine.

I should have inserted the word 'easily' and also perhaps 'on my driveway'.
I just advised based on my experience and though I think I did manage to inch it along a few inches with just a half ton of lathe lowered onto the legs on the dead smooth part of flooring I wouldn't want to give the impression it was just gong to be a doddle with a 1 ton pendulum across crazy paving. I quickly reverted to plan B - trolley with 6 inch wheels.

BTW I meant to add, based on my experience, it is not a good idea to rest big tall things on normal everyday pallets which turn out to be rather flexible under those conditions.

This is how I moved a complete Bridgeport single handed, inverted head into travelling position to lower centre of gravity. Only needed to lift it just clear of the deck onto the light blue frame. Holes are threaded (welded on nuts underneath) to secure mill base. Use of lifting eyebolt no problem, "Bridgeport approved"!

Edited By KWIL on 01/08/2013 19:32:34

Edited By Muzzer on 05/08/2013 07:27:51

Edited By Muzzer on 05/08/2013 07:29:18

Perhaps the Chinese engine cranes are rated similar to their trolley jacks, the local Pollytech tested the jacks a few years ago, and published the result in the news paper, can't remember the figures, but I think they all failed before they reached their rated max weight, so for example it would be best to halve the rated weight. I know my two ton jack does not like a three ton plus truck on it, it's previous owner did just that, and the cup seal on top of the piston tried to extrude its self between the piston and cylinder. That's how I got it, and repaired it, think that one was made in Austrailia. Ian S C

Many thanks to all for the kind advice.

Regards,

Steve

Hi,

I can confirm that my "bridgeport" badged bridgeport of UK origin does indeed have a UNC thread form on the eye bolt hole. I got myself a 2 tonne 3/4" 10 TPI UNC eyebolt from amazon dot com just shy of US$13. (usual disclaimer)There was me thinking amazon were for books, cd, dvd etc... The us site has much more. I won't lift with this but I am going to use it to help my stabilise the mill when I take it down some stairs to my houses back door workshop entrance. Yes I am nervous, but I got a boxford lathe, elliot shaper and rapidor hacksaw down ok so far...

regards,

Steve