Member postings for Ajohnw

Measure the V and look on simplybearings web site. The do a wide range of widths of V belts including narrow starting at 4mm and going to 8 if I remember correctly. There are also some industrial sewing machine belts on ebay with sizes given. My feeling is that the narrow cogged ones from s'b' are better.

If round belting actually fits into the V it needs rather a lot of tension to get it to grip well and it wont be as good as a v belt anyway.

John

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For turning black bar free cutting mild steel is better than bright drawn. I understand this is down to it cooling naturally so there is less stress. Bright drawn is then processed cold which will add stress and it varies. Machinists did have a term for the bad stuff - park railings. From WWII when they were melting anything that could be found. I have had a supplier wait for some "good stuff" to come in. He cut hexagon disks for me from plate. I expected cut bar. Only ever happened once and it turned rather well. Some doesn't.

I have no information on annealing it other than red heat and slow cooling. Castings are much the same except lathe manufacturers traditionally leave their castings lying around for a very long time before doing anything to them. This is why some people prefer to fabricate rather than buy castings especially for tooling. It also suggests that at least in this case heat treatment isn't the best way to go about it.

John

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You could make up something for yourself. A 2,800rpm pump motor with one of the thick recessed wheels mounted on the spindle and put it on your shelf end on

The type of wheel I'm referring to is this one but I would probably try to find a finer grit but this one would be ok especially if you currently sharpen by other means - I polish mine up with a stone.

**LINK**

You could mount the usual wheel edge grinding rest and use it side on and something fancier for the side of the wheel.

When looking at cheaper 6in bench grinders the power they specify seems to be input rather than output. On that basis 250w in seems to be ok. Output will be a lot less. I suggested a pump motor because they are sealed. The plates these grinders have to support the wheel are generally pressed so have wobble built in. Machining up decent ones at home should make a distinct difference as they can be an accurate fit on both the wheel and the motors shaft. There usually isn't much space for that sort of thing in the commercial ones - otherwise I might suggest modifying one of the them and forgetting the wheel on the other end. - unless for some reason the whole thing is turned around because the wheel on it is needed.

You could of course just fit a thick wheel.

John

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There isn't really a good alternative to paraffin other than maybe Gunk - an automotive engine cleaner but the problem is it's a soluble oil washed off with water. Petrol can be used but has it's obvious dangers. IPA will dissolve oils after a fashion and might even work out cheaper than paraffin. I just paid £7+ for 4L of that. Disgusted on the price and the fact that it was 4L where as most gallons have gone to 4 1/2 or 5 containers.

I'd guess that the only use for paraffin now is green house heating or cleaning up oily stuff. I just looked on ebay and the first 4L that came up was listed at £34 rrp £47 so I'd guess the local source is cheap - hardware store that also does gardening bits and pieces. There is also a 4x4L pickup only at £25 in Maidenhead. To far away for me.

John

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Once some one has enlarged a hole in brass they will know that the drill might grab and react accordingly next time. The noise it may make could also concern people. If they have a dodgy tail stock they might even tighten the barrel clamp a tiny bit as well.

Or they could modify a set of drills.

John

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-2 if it's going to be bored why bother. Drilled smoothly a clean hole will be produced. If the drill grabs don't let it.

One of my first lathe purchases was a set of blacksmith drills. Loads on ebay. They allow holes to be drilled up to 1in or 25mm in stages and all have 1/2in shanks. Mine are the black ones.

Sometimes it's difficult to get a hefty boring bar on a lathe say 16mm dia. My Boxford has a Myford branded qctp. What they did to get the additional tool height was to add a plate to the bottom and use the same 1/2" holders. It's fairly easy to make a separate holder for a larger bar. Block of steel and T bolt to fix it in the usual slot. Drill through it to suit the diameter of the bar and add clamping screws. If you might want to get these screws out after much use make sure they are high tensile ones and just to be sure chamfer the ends a little.

The hole for the boring bar needs to pass close to the fixing hole to help reduce twisting moments. The base of the block area shouldn't be too much smaller than the normal tool post really and do make sure the bottom is flat and well finished. If block turned in a lathe it will be concave so lap it. They can be made out of round bar too.

The cutting edge of some of the indexed boring bars is on the centre line of the bar or better still for boring a few thou above it. In this case the hole for the bar can be formed with a drill from the headstock but it would be best to ream it as well.

Super fancy ones can be made as well. with several hole sizes.

Maybe a bit over the top in this case but twisting moment on the holder is very low as the bar passes though the fixing's centre.

John

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Drills and milling cutters are HSS and the type used varies. M35 and 42 have been around for a long time. M42 tends to be too expensive in my view M35 not too bad really considering it will generally stay sharper for longer than the cheap stuff. M35 is sometimes described as 5% cobalt or HSSE. From just a cutting perspective the higher cobalt content allows higher cutting speeds before heat at the cutting edge spoils the temper. That also helps when the tools are ground. It's very easy to wreck the temper of some of them during grinding. It's best to not take advantage of the higher cutting speeds at home unless people wants to resharpen often.

The M's as I understand it are American designations. HSS has traditionally been sold by manufactures name with the ingredients on the side of the packet they were in. Frustrating if a brand was excellent but is no longer around.

It's worth looking in Cromwell's clearance section for tool bits. Names keep changing when new stocks come in so they seem to sell the last of the earlier ones there. Harry???? on Ebay sells M35 tools bits. One of the few that do.

When it gets to stellite and tantung g and crobalt etc cutting temperatures can go up again. If used at normal cutting speeds what ever those are they should stay sharp even longer. Some of these shouldn't be chilled in water when ground as they may fracture.

Cutting speeds really are just somebodies idea of speeds that will give their idea of a reasonable tool life.

John

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It woud be best to put some 3 in 1 or other light oil on the wet and dry to stop it clogging and to get a cleaner finish. Soapy water can help too if nothing else is available.

A local glass merchant might be able to sell you a square of 1/2 in plate glass but unfortunately many only stock laminated now. If that is put one something reasonably flat it can make a good flat surface. 16mm mdf is often very flat, also pieces of kitchen surface. Those are easily checked with a rule.

Rather than wet and dry you might like to try some papers 3M make. They are are actually a plastic film for lapping and finishing and go down to sub micron levels. A number of companies offer sample packs but i suspect the best value ones are from cousinsuk.com. There's are full sized sheets. They are a watch and clock bits type company also useful for acids if you are local to them. The papers are mostly being used by woodworkers to get tools amazingly sharp at the moment but should have uses for all sorts of finishing.

John

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Edited By John W1 on 18/07/2015 17:10:54

What material is that ?

John

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That sounds like an extremely good idea to me. It's a little like having a supply problem and getting no where, posting on some forum and all of a sudden it gets fixed.

There is another aspect to this area. I was posting in another forum and the thread was locked by a mod. I emailed him pointing out why the quoted reason for locking it was invalid. Probably wont get a response. The most likely reason for their action was when I used telescope mounts as a comparison to buying hobby lathes pointing out that lathes were not so bad. I mentioned an EQ1 mount. The world would be a better place if it and some of the others just were not sold as far as astronomy goes. Just about every body who would read the thread has been there and is well aware of that but suppliers wouldn't be very happy about it getting around.

Just used as an example that shouldn't cause any upset round here. My feeling is that when such things are true they should remain up what ever suppliers think but people have to remember that in this forums area they have a tough job. Selling cheap, keeping people happy and running their big BMW and some do at least try.

John

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If looked at logically for all sorts of reasons it's not a good idea to use one's full real name on the web. Lots do and don't suffer in any way at all but some do. Rather badly in a few cases.

John

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My Diana has gone - it's illegal now.

As there are some gun type people about and it's vaguely connected to building one I have one gun with a problem. C02 and very winchester like. It's pretty good in the summer, nvg on cold days. It went away for the winter and came out again next summer. Stuck the sparkets in it and gas hissed all over the place. Several seals must have gone in a rather short time. I can't see anyway of getting it apart to replace them.

It takes several pellets in a small round magazine and next one is selected in the same fashion as a winchester.

Any idea on how the thing is taken apart? This is the one

**LINK**

I still sometime still get the urge to go out and shoot at a swinging snooker target and like this one.

John

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I think it would pay the OP to spend some time looking around here

**LINK**

There are specific stepping motor drivers that are easy to interface with that are also cheap and easy to obtain. There is also a lot of library code available including driving stepping motors and all sorts of other bits and pieces.

Interesting that some one has worked on replacing a lathe gearbox. Personally I would be looking at a geared down stepping motor to obtain lots of torque from a relatively small motor. Also thinking what the rotary encoder pulse counts meant in linear distances on thread pitches.

There is a yahoo electronic lead screw group that initially started from some work a German did that just used logic chips. Not sure what processor it uses now. I do know from following that some time ago that some people were effectively using servo motors to drive the lathe to get rapid speed control when the cut started and the motor speed dropped a little. I've never looked at the code so don't know if the problem is down to that or the software approach. Could be that some people just want to cut threads very very quickly so run at high speeds.

Must admit I became rather excited when stepping motors first appeared commercially thinking a rotary table / divider etc but once the detail is looked at things aren't so simple. The step tolerance can even be a problem. However they are a lot cheaper now.

John

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Edited By John W1 on 16/07/2015 20:36:57

Curiosity - what is a single stroke pneumatic?

John

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This is way of target (pun) from the thread really but I agree with Vic except from USA practice and other info 18 is probably ok but problems get worse as power goes down.

Ballistics can roughly be scaled after a fashion so this page can be used to put power into perspective in terms of accuracy in particular

http://news.bbc.co.uk/sport1/hi/olympics/shooting/4725546.stm

Power 2,500ft lbs, bullet velocity - from memory they don't even go subsonic until something like 1,000 yds. The V bull isn't that small and the target itself is rather large both are easily visible at the distances mentioned and further. They use target sights not telescopic, 2 round holes. The ranges have flags dotted about on them so that people can adjust their sights to account for even a breeze let alone any wind. Both often vary along the path of the bullet.

Rabbits, air rifle at 35 yds no, maybe with something of an iffy kill aspect at 35ft or even less. The comment that is often made by people is that oh you need to hit a very particular rather small spot on their heads. Honest gun shops will sometimes mention that even pigeons can be a problem. They do get people come in who have pigeon problems. This area touches on why people with fire arms licenses who shoot animals always go for more power than they theoretically may need. All sorts of things come into it even shooting up hill or down hill and etc The other aspect is clean kills and risk. Risk limits power.

There are plenty of things that can be shot at local air rifle and even some gun clubs that allow both types of gun. Those can also often train people in the use of fire arms with club guns. Some air rifle field sports are very difficult to master. There is plenty to do without usually maiming animals.

I'm a frustrated gun slinger. My eye accommodation isn't really good enough for target sites any more and worse still while I was near a lighting strike that killed several people the end of my elbow was mildly damaged and I can no longer shoot prone. Sad as I was in the middle of taking up full bore which is very challenging. Far more so than others I have tried. The beebs description of full bore shooting isn't entirely accurate. The targets have trenches in front with people in them who mark the positions of shots with a rather long pole.

John

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I mentioned the advantage of a true universal mill to some one recently on here who was lusting after a Bridgeport. Trouble is though finding one that has the gear with it and is in good order. Some of the smaller ones are also surprisingly heavy and are likely to be odd not well known makes with what seem to be rather large motors.

The brown and sharp book I have and mentioned is also on the archive, several versions of it. One thing it adds is the best route to designing a set up and why. For other aspects the book I linked to in my opinion is a lot clearer. Just search gearing.

John

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I shot several rabbits at well under 35yds so they must be made of much stronger stuff where I was shooting. Perhaps they were wearing crash helmets. Typical FAC air rifles give a good idea of what is really needed for pest control. That's what they are generally used for, cheaper than rim fire and safer too but perhaps not now that certain calibres are available that splinter on impact so that ricochet isn't so much of a potential problem.

My Diana would have dated from the 50's. Probably mid. I have no idea of power but I used to shoot precision 22 rim fire rifle at a works club uk style, out wards scoring targets, bull equivalent to hitting a pin head. I took it there a couple of times but there was a problem. If I hit the bull cleanly a flattened pellet would bounce back and hit me on the head. More recently I took a pcp to another club and used it at 25 yds. No where near as much power or accuracy as a result. In fact when lamping rabbits with it the pellet can actually be seen travelling for a long way towards the target. At more realistic distances it can be persuaded to shoot more or less pellet on pellet.

John

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Personally I wouldn't advise some one to buy one unless they are prepared to put up with problems I have already mentioned especially as an only lathe. The reason I owned one and some other small lathes is because if I needed anything larger I could use the machines at work in the evening. I'm a design engineer but my indentures kept the health and safety people happy.

Neil has shown that a lot can be done on the mini lathe but my feelings on first lathes is that something like this is a far better option

http://www.warco.co.uk/metal-lathes-metalworking-lathe-machine/15-wm-180-variable-speed-lathe.html

Size wise it will probably take many people a long time to grow out of it other than one problem I will come to. It has the features a lathe should have but a T slotted cross slide can be very handy if people want to be able to do everything that mags like ME show a lathe being used for. Having never been near one I can't comment on turning or precision. The drive set up may have problems doing things like drilling 1in holes as DC motor control like that doesn't increase torque at the cutting tool in the same way as gears or pulleys do. Few small lathes will drill 1in in one go so it's a question of how many drills have to be used - and if the centre distance is big enough to take blacksmith style drills. 300mm isn't brilliant in this respect but does leave some room for the work. Not much though. Something like 100mm less the thickness of the chuck holding the work. Or get the drills reground a lot shorter. This applies to lots of sizes of drill in practice. This is why 18in centres has been rather popular for a minimum, circa 450mm.

Metric / Imperial. I can understand people who have 2 machines wanting them to be the same but machining is the task of producing items of a certain size the units on the machine don't really matter as they can be converted. I did look at going metric and at the time didn't realise that Boxford had an answer to screw cutting metric threads and that aspect put me right off. I even looked at used lathes from the continent and found that these too were not fitted with indicators. I'm not sure what they do on metric 180's but do know that to cut most of the pitches without having to stop and reverse the lathe that the indicator would need a choice of gears to fit to it. Most screw cutting in practice is done with taps and dies but I see lathe reversal as a very severe disadvantage. I have cut metric threads at home on a Hobbymat. It's gone now so last time I needed to screw cut a metric thread I part cut a near imperial and finished it with a metric hand chaser rather than fitting the correct change wheels to convert the gearbox and having to reverse the lathe. Pity it isn't so easy to do internal threads but lathe reversal etc cutting true metric threads into blind holes isn't much fun anyway. I also wonder if lathes like the 180 always use an imperial lead screw and just change the slides over. On the other hand I did see complaints in USA forums some time ago that some lathes just had the dials changes one way or the other on the basis that 2.5mm = 0..100" which of course it doesn't. I'd hope that aspect has been fixed now.

John

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I'd say the plate is probably made from continuous cast iron these days as it would be cheaper than what is usually done with lathe castings to de stress them.

Afraid if I made a copy of this layout I would revert to the old style clamping - 45 degrees either side of the centre line at the back. They could have easily put them more conveniently for users on the front of the older Boxfords and didn't.. The casting would take them in either position. I wonder why? Not really. I'd probably use steel but it bruises more easily than cast iron.

John

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Captain raises some interesting points -

Anyone who wants to shoot a rabbit and there are a fair few who do must seek the land owners permission. My problem is that I feel it's cruel given the power the guns have.

Afraid it is possible to tamper with air rifles of both types that will pass tests but I would ask anyone who knows how to not pass on any details. In some areas of the country one method is pretty common. Why - because to kill a rabbit with any certainty it has to be used.

Crime involving real fire arms isn't always reported nationally so I would take comments that it is falling with a pinch of salt. Armed robbery may be on the decrease but frankly I doubt if things like drive by shooting and related are.

John

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