Member postings for Ajohnw

This sort of thing happens on Linux sometimes. Could just be that your java runtime isn't up to date or has been corrupted some how. Some disto's come with the open source versions. Eventually it generally becomes to dated to work on some sites.

Of late I have been using Chromium (Not Google Chrome). It should be available on your distro.

The other possibility is that some one has been tampering with the forum software. Generally it's only checked against windows and often bad practices cause problems with othe OS's and sometimes older versions of windows. Newer ones too.

John

-

Edited By John W1 on 06/12/2015 17:01:49

20 degrees sounds fine to me for aluminium. Do you have back rake as well, maybe around 15 degrees. That will tend to lead the swarf away from the work and in a sensible direction.

The standard fix for this sort of problem is a swarf hook. The nearest thing to a sensible one off the web is this

**LINK**

However I would bend one up out of 3/16 or 1/4 mild steel with a bent handle on one end.

I need a new keyboard - missing letters. You could increase the clearance angle into the cut to circa 20 degrees as well if the machine is struggling to take deep cuts.

John

-

Edited By John W1 on 06/12/2015 10:12:00

Edited By John W1 on 06/12/2015 10:16:07

Putting all of the problems together I would still use the tube and make the ends in one piece and then loctite it all together. Keeping the tube will keep the weight down compared with it all being solid.

There is always a chance the the bore of tube isn't concentric to the outer diameter so I would be prepared to skim the entire thing up after assembly. You could do this after welding it all up anyway maybe even fabricating the ends.

John

-

Edited By John W1 on 06/12/2015 10:02:17

Typically when people show the revs being slowed right down they only do work with it for 10 of seconds rather than many minutes.

While talking to Brook's and Mitsubishi they did admit that some people do burn their motors out. They are a bit cagey about it. Some of the inverter retailers say everything will be ok. TEC produce charts in one of their catalogues that show just what anyone who knows about the subject would expect.

I did get one interesting but unofficial comment from Brook's. They doubt if one of their 1400 rpm motors would burst it's armature at 2,800 rpm. Many people who convert lathes from single phase fit a more powerful motor so that the torque is increased from what it would be when the speed is reduced. This doesn't help with overheating other than a bigger motor may take longer. I up'd 1/2hp to 1hp and also went for a 6 pole motor. I also changed the motor pulley to suite what I need and set the inverter for 40 to 80 Hz.

Hopefully it's bomb proof. It is very easy for me to change the countershaft belt setting though - if I need to also put the back gear in.

John

-

Edited By John W1 on 04/12/2015 15:31:47

The lathe uses 6003-2Z bearings so sealed both sides and in any case as there is a plate that is part of the spindle on the front it's doubtful if any grease could be pushed in. The same plate may make it difficult to get the front bearing off. Sounds like Jason may have an answer to that as I believe his lathe has the same sort of chuck mounting arrangement.

I think Opti do state some where that they use hardened bearings but .............................

Boxford seem to have a bearing heater just to make sure that the front bearing is difficult to get off. Worse still it seems that they use it on the rear one too so adjustments need a drift and a hammer unless some one has been in their before.

John

-

Many bearings are sealed for life Brian. There isn't a clear definition of what life is other than at some point they become unfit for purpose.

The other problem with lathe bearings in particular is that as supplied on a new lathe they don't have much grease in them at all. If more is added it leads to more friction and more heat. They all tend to gloss over that aspect even if the lathe has grease points for the spindle bearings. Instructions vary. Wabeco for instance say lubricate the lot every 8 working hours even the spindle bearings and every 500hrs check bearing heat giving no idea what it should be. Ok if some one has a new lathe as they can feel it and get some idea how hot they should be. I'd assume this is taking account of that the lathe may have done a lot of high speed running. 2,500 rpm is pretty fast for a 3 morse spindle. Traditionally it would be 1500 rpm max. Even slower earlier on.

I need to go out but when I get back and I'll look and see if it's possible to pop a bit of grease in now and again, or maybe some one else will.

John

-

Bearings are supposed to run a bit hot Jason. Perhaps Brian can feel how hot under the rear bearing with a finger in the spindle bore. If it's ouch hot something is likely to be wrong. Very warm should be ok but it this is a bit subjective and just my opinion. It works for me. I also check at max speed, They will be even warmer then.

I'd guess that a major source of heat is the motor especially if Brian is running it for significant periods. That all by itself could warm the entire lathe up. It wouldn't surprise me if the motor was too hot to touch or HOT after say 10 to 15min running. That is around the same period needed to get the bearings as hot as they are likely to get.

John

-

They state 1 1/4 D for ferrous and brass, hardness <= or > 160 BHN and 2 1/2 D for other none ferrous, soft stuff such as aluminium and copper I assume.

LOL So much for my guess.

They also mention that BS messed up the tolerances on studs such that they might turn out not to be an interference fit in the hole - explains all of those irritating ones that unscrewed rather than staying in place when the nut was removed.

John

-

Maybe it's down to model " ? engineers ? "

Must admit though thinking back to work on car engines studs do go in further than the engagement length of nuts.

That's interesting as the reason for nut thickness relates to strength. When tightened both distort due to pitch errors and it's argued that too much engagement length doesn't increase the holding power at all as there will be more distortion.

I have a feeling I will be getting machinery's out to see what they have to say on the subject of studs. Maybe longer engagements are used to help keep them vertical if knocked. 1D from that point of view would be marginal. I'd guess 2 maybe 2 1/2 D.

I have never designed anything at work that uses studs. Plenty of thing that use unbrako's - press tools and jigs and fixtures etc.

John

-

I'm registered with them and get emails. When I retired I considered going to engineering auctions buying and selling on but decided that I'm happy as I am.

There are several auction houses about that specialise in engineering type things. Just google and then register. Has to be said that web bids have upped the prices a lot at times - companies buying for themselves.

No idea why now as I have no room left for anything that might crop up.

John

-

There isn't any problem registering with these people or others. The main problem is lots of emails about auctions all over the world. There used to be plenty of smaller ones around B'ham but very little for some years now.

It's interesting how the various education areas sell. In the USA everything from universities gets auctioned and they seem to do it themselves. Schools here often sell to people they know for peanuts really.

John

-

Taping lubricants always remind me of an instructor that probably trained as a tool maker in the 1930's. He had managed to get a bit of sperm whale oil which was reckoned to be the ultimate tap and die lubricant. It fell into disuse for obvious reasons. From the wiki it seems a "greener" alternative with similar properties is jojoba oil.

**LINK**

This would have the additional advantage of rejuvenating skin and hair and curing all sorts of things as we grow older. Just rub it on or take a bath in it etc.

John

-

I wonder if some of the problems with fine taps is down to the depth they are used to. There is one thing common to just about any screw fixing done correctly and that is the relationship between the diameter of the screw and the engagement length with what ever it's screwed into. Nut thickness is a typical example. The relationship us usually just over 1 diameter. Tool rooms I have been involved with shorten bolts if needed so the engagement length is in the range of 1 to 1 1/2 diameters, same order as a nut in other words. Maximum strength. There is no need to tap much deeper than that.

Must admit 1D gives me the wobbles so always go for a bit more and also often can't be bothered to shorten screws and bolts. On the other hand 10BA only needs fully tapping to a depth of an 1/8" tops really and that is very likely to save breaking taps.

John

-

I wonder how many people had a period in very early school life when they and others used the word ift rather than if.

A infants school teacher had to tell lots and lots of people over and over again to stop using it. Pity really as it sounds nicer than if. I wonder ift it was usual or uncommon.

John

-

Edited By John W1 on 03/12/2015 14:48:26

Edited By John W1 on 03/12/2015 14:48:41

Edited By John W1 on 03/12/2015 14:49:14

You should rotate the tap backwards every 1/4 / 1/3 turn to break the chip Brian. A few full turns to start the thread are usually needed but the chip size is small then due to the taper on the tap. There is also the question of how much downward pressure to apply. Can't help you much on that aspect but some is needed otherwise the teeth that have already cut will cut some more due to the cutting forces caused by the new threads that are being cut - they try and push the tap out rather than in. A little pressure is needed in practice, around the same amount that is needed to get the thread to start cutting "crisply" when most of the taper has gone in.

I've generally managed by just using 2nd cut and plug taps. The 1st cut one is definitely needed on very hard materials and can be a good idea when very fine tapes are being used. I don't see M2 as being very fine just bordering on that area.

The pressure aspect applies to dies too.

I have my tin of supa dupa tapping lubricant as well. I'd guess many have. Can't say as I am impressed. I often scrape a bit off a bar of hand soap onto taps. It's a type that has some sort of moisturiser in it. LOL I've mentioned cutting oil several times.

People often mention paraffin / kerosene for aluminium. The key word is more volatile than substances used on other materials. It's oily and evaporates readily and that aids cooling which helps prevent the aluminium from melting at machine tool cutting speeds. In practice I have never seen it used. Oil mist and suds yes but never paraffin. The suds tank would have to be emptied and filled up with it. I'd guess if any one really ever used it this way they would also mix in some sort of oil. All I have ever seen been used even when grinding it is lots and lots of suds.

John

-

My school had a screw cutting Model A and a none screw cutting version. They have always been popular in schools more or less from day one. First time have ever heard of the castings deteriorating. Lathes co uk reckon that they didn't harden beds. That's known to be incorrect but it isn't clear when they started offering it. Unhardened they aren't really any different to other makes with similar gib sizes however they are a much better design than many.

The downside to buying them is that they were very popular with self employed turners that would usually be doing batch work for various companies. Often lots of it as the work provided a good income. This sort of thing wears a lathe out pretty quickly. They have also been popular as a workshop machine with varying degrees of use. VSL's are more popular for that in more recent years due to the spindle bore - on some.

They came to fame due to the USA bringing over the same size Southbend during WWII. I'm told by a relative of some one that was involved that we Brit's didn't rate lathes of that size at all but soon changed our minds. Several near clones popped up. The Boxford, Viceroy and the Smart & Brown Sabel. All copied the general proportions of the Southbend. THAT is the important aspect. In Boxoford's case I'm told many parts are exactly the same. Headstock's though seem to be distinctly different or became so rather quickly. The none screw cutting A's seem to vary too. The one I used at school was a low mounted rear drive. I have seen others much like the ME where the motor is directly behind the headstock.

The attraction was that they are a lot of lathe for the money. Sort of rather upmarket budget and didn't take up a lot of space. People reckon that Boxford could only offer the ME in a similar price range to a Super 7 because they had a lot of Model A castings about. Even then most sold were more expensive.

John

-

These "proof masses" will be allowed to free-fall inside the spacecraft. A laser system will then attempt to monitor their behaviour looking for path deviations as small as a few picometres. This is less than the diameter of an atom.

What's wrong with that version?

John

-

I lot depends on the attachments that come with the lathe. It might be best to post a photo of the lathe and any bits and pieces that go with it. Often people have a faceplate, catchplae, 4 jaw chuck, steadies, drill chucks, centres, a micrometer saddle bed stop, various types of tool holder and they can sometimes come with rather a lot of gears for screw cutting. My Boxford for instance is an imperial one and came with around 25 including the metric conversion gears.

The downside on price is that it's a model A and rather old as they all are. Condition is most likely to relate to what the lathe was used for. Some are used daily for years. Some hardly at all. The upside is parts that come with it..

John

-

Might interest some if they happen to be up that way

**LINK**

The toolroom lathe comes with some kit. I wonder what it's like wear wise.

I was talking to some one who was selling an ex 2ndry school machine recently. It seems that the new school was just over the road. Rather than move the stuff across they sold it all and bought new. They didn't use an auction company to sell either!

John

-

There is cast iron and there is cast iron so properties vary according to what's in it.

**LINK**

And there are variations within the types too eg

**LINK**

I'd guess that the continuously cast iron bar that is most likely to be supplied in the UK is this one

**LINK**

There are several other types in the index on that page. SG iron for instance can go up to 700n/mm^2. I notice that Arc offer an sg iron milling vice. The sort of thing it's used for.

John

-