Milling machine spring assist lever failure

[Former Member2Participant @formermember2]

[Sub MandrelParticipant @submandrel]

I have disconnected the spring from my mill. It's 'neutral' position on mine is straight up anyway, and it make no perceptible difference with the head at the top of its travel.

I may replace it witha sash weight on a rope over a pulley.

Neil

[Gray62Participant @gray62]

I dispensed with this system a long time ago on my X2 clone and replaced it with a gas strut obtained from the local breakers yard for a couple of quid. I used one from a Rover 45 but pretty much any will do that are of suitable length/travel

CB

[Ian S CParticipant @iansc]

Seems an odd place to use cast iron, was it an origional part? Ian S C

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Ian S C on 26/05/2013 13:32:51:

Seems an odd place to use cast iron, was it an origional part? Ian S C

.

Odd … and particularly dangerous !!

MichaelG.

[Peter G. ShawParticipant @peterg-shaw75338]

Hi Gray,

My Warco MiniMill uses the same silly idea and I also broke mine. But mine must be steel because I managed to weld it back together and so far it's still holding although to be fair, it hasn't exactly been over used.

In my case, the spring isn't strong enough to return the head to the top so I tried winding up the spring with the inevitable accompanying engineering language! It still isn't strong enough and I have plans to replace by a boot strut someday.

Peter G. Shaw

[Jeff DaymanParticipant @jeffdayman43397]

"admittedly there is the cost of the press tool to consider,"

Hi Graham, Not sure if your machine was built in Europe or Far East, but just FYI the cost of stamping tools in the far east has dropped like a stone in the past ten years. It has never been less expensive. Also these days a part like that would likely be laser cut or waterjet cut up to yearly qtys of parts around 1000 pcs. After that a set of dies would be cheaper.

I agree with all who have said the part design is not a good one for cast iron. The part should be made of steel for safety, if made to the shown shape and dims and under heavy spring tension.

(As mentioned before, those fitting gas filled struts should be aware that manufacturers rate these for 2000 cycles only. If you can get a cheap spare when buying the first one, it would be a good idea if you use the mill and move the head a lot.)

JD

[Peter G. ShawParticipant @peterg-shaw75338]

Funnily enough Jeff, the struts I have seen recommended for my mill are for a small Peugeot car and I was already thinking about buying a pair. Not for the reason you gave because I did not know about that limitation, but more for longevity if that particular model disappears.

Hmm. Not very well written. Perhaps it's getting too late. Anyway hope you can make sense of it.

Peter G. Shaw

[Russell EberhardtParticipant @russelleberhardt48058]

I just removed the spring assist on my X2 mill. I think it is only useful if you are using it as a bench drill. For milling it is superflous.

Russell.

[Sub MandrelParticipant @submandrel]

Now there are several of us with redundant lifting arms, who can think of the best use for one?

Neil

[Ian S CParticipant @iansc]

Some bits of steel, and a welder, it would not take too long to fabricate a good working lever with some standard sections of steel, all thats needed is a boss with a keyed hole. Ian S C Ooh, and a clean up with the angle grinder, and a coat of paint.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Stub Mandrel on 27/05/2013 12:51:05:

Now there are several of us with redundant lifting arms, who can think of the best use for one?

Neil

.

Neil

I think the best bet might be to collect them all up; put them safely inside something with more tensile strength, and use the lot as a Boat Anchor !

MichaelG.

[BazyleParticipant @bazyle]

Lots of potential for lathes that have lost their change wheel banjo, gear hobbers, dividing heads. What size is the hole?

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Bazyle on 27/05/2013 14:55:29:

What size is the hole?

12 mm. I still have all the bits I took off the SX2P mill when I converted it to CNC. They are in the "might come in useful some day" box.

Russell.

[BazyleParticipant @bazyle]

Too small for my dividing head then. Also perhaps variable lenght mandrel handle (gently does it), variable length lever for feed on shaper.

Broken outer end is a bit difficult to use without further breakdown as just material which is cheating in this context but perhaps crosshead slide?

[Sub MandrelParticipant @submandrel]

Some potentially interesting bits. The spring sits inside a large cast iron (?) 'cup' with thick walls. Two cast iron bushes (one a force fit on the spindle). the spindle itself, various smaller bits and a big spring.

Beleive it of not my lever is ground on both sides, thickness appeared to be within 0.001 thou measuring at each end (just above and below 0.324&quot, so I thought cheap parallels – but 0.330" in the middle of one side, and it is slightly curved

Yes a banjo for a geared dividing head would do, the thickness and the width of the slot are accurate enough for that.

Neil

[Les Jones 1Participant @lesjones1]

Hi Neil,
Thats what I call precision. What do you use to measure to 0.000001 of an inch ?
I suspect this could be a typing error !

Les.

[Sub MandrelParticipant @submandrel]

Hi Les,

My microwave interferometer of course. Don't you have one?

Neil

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Stub Mandrel on 27/05/2013 18:39:53:My microwave interferometer of course. Don't you have one?

Not good enough. For 25 nm resolution you would have to use an Extreme UV or X-ray interferometer

Russell.

[dave greenhamParticipant @davegreenham19379]

Hi all.

the Mill is working great now, thanks to Gray. But, can't help thinking. That if the prongs of the tuning fork had hit Gray in the temple, it could possibly of killed him. So apart from being a crap design it's very dangerous . The depth stop on the m/c is also made out of cast. That broke as well, with very little pressure on it.

thanks again Gray.

best regards

Dave

[Sub MandrelParticipant @submandrel]

> The depth stop on the m/c is also made out of cast. That broke as well, with very little pressure on it.

Mine went years ago, I keep meaning to make a steel one, except I never found it very useful, the contact area is to large for precise setting, I just rely on a DRO.

Neil

[BazyleParticipant @bazyle]

Latest ME has the use for these brackets – milling vice job positioning end stop. page 782

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