Member postings for Ajohnw

I just clicked on the link Neil using a browser that has never been logged into Ebay. Still works for me including the images.

Then tried from a browser that is logged into ebay. Same result except had to click see original listing.

Looking at it the tailstock is split. That has been updated to one which closes onto the dovetail bed in the more normal way so suspect it's an early one. Looking at what Sherline say about the over all accuracy of the machine it doesn't seem to be as good as would be expected on a small lathe of this size.

John

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Thanks Rod. Never thought of that. Probably influenced by an older Peatol - if such a thing exists. I have always wondered despite the earlier comment.

John

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I have been nosing around for something easy to use and also have the problem that I run Linux. This one may be of interest - all platforms

**LINK**

Have I used it yet ? No, I don't know anything about 3D packages. Must admit as well that having spent several years in a TDO I don't really have any problems working in 2D. Actually I would probably prefer a package that generated 3d from that. I'm not sure if any work that way. Then comes output to cnc machines. Another area I don't know much about.

John

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I wondered about that. I know that Taig or Peatol did make something other than the current one. I went to a model engineering exhibition ?? years ago and some one was berating Peatol for spoiling the lathe and cheapifying it. This one does look entirely sensible.

John

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Interesting micro lathe just sold on ebay. Not one I have seen before

**LINK**

It went out of the price range I would pay before the auction ended but I had a feeling some one would bid right at the end - they did.

John

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I came across this while nosing about.

**LINK**

Only looked quickly. A brass boiler to hang over the fire, various engines and some drawings but not scanned that well as they were fold outs in the original book.

John

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When I measured belts up and picked a particular width I found I actually needed the next size up. Fortunately they aren't that expensive.

John

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Arc do seem to give a reference - things like D6A2 and D4BT9 on the tapered wheel. These don't relate to the size of the wheel. They did have some more expensive D1A1 wheels. The others are D12A2.

Could be that the D is the diamond mesh size and A and B the bonding. RDG list D76 on ebay.

I have a chinese wheel with several markings. Going on that D100 is equivalent to a 320 grit.

It's interesting to note that things like cylindrical grinders will produce a much finer finish than the grit size they use. Not a precise way of looking at why but each piece of grit is a cutter so the speed of the feed sets the finish.

John

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Edited By John W1 on 22/07/2015 17:48:27

I would probably make them in 2 part using a self centring 4 jaw for the square plus small hole for the spigot I would leave on the pointed part - assuming that I could get 1/8" square brass and that being 0.013" under sized wouldn't matter. Or mill up the square bar 1st but in that case they may as well be solid.

John

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Agreed, a decent hole saw that would withstand the journey through the material would probably cost more than the smaller piece of bar.

John

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cm and the other one whose name I can't remember, dm ?? that are 10 of those are used in the originally metric countries but ISO bless them have decided that only multiples of a 1000 can be used and that the rest don't exist.

Why use them - there is something vaguely obscene about saying something is about 75mm or 0.075m long. Equally it wouldn't be so daft to say something is about 800m away or 0.8km but 8 what ever they were called would give a better idea of accuracy. The mm units imply more accuracy than might be intended. For instance how accurate would some one expect about 6in to be be? If I measured something described like that - doesn't matter much - I wouldn't be concerned even if it was 5 to 7in.

Leaves me wondering what happens if people are only taught mm and m - guess they would only measure things rather than saying about 75mm long or discover cm and others and think in those terms. They could of course add a tolerance to their estimation in some number of mm.

Be thankful attempts to metricate time and the globe failed. In some ways base 12 makes a lot more sense than 10. Perhaps kids don't have to learn their 12 times table any more.

John

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How far back do the digital copies go especially on ME ?

John

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Sorry. I don't really see trepaning as an option so thought that had gone out of the window.

In principle the work could be done with a trepaning tool under 2.5mm thick or via a change of sizes but it would need some rather careful grinding to avoid weakening it too much - the same order of precision ground into parting off tools, rather shallow angles. The side facing the inner diameter can be square to the top. The angle needed on the side facing the outer diameter depends on that diameter. The tool would finishes up like a narrower version of this

It's not a lot different to parting off really so in principle ground correctly a 1/2in HSS tool bit should be able to do it. 2.5mm might be ok if the clearance needed on one side doesn't neck it in too much This one was ground to work on diameters larger than something around an inch and a similar tool has been used for trepaning but not after a particular core diameter. The in feed it can handle in one go is small due to the width and machine power so it was used to face an area away that gets smaller as the cut deepens.. This one is 5/16 HSS. I use it for boring shallow parts. The only time I have trepaned with a tool like this was on a Peatol. No chance of drilling a decent sized hole to bore out. A very large washer around 5/16" thick, 4" dia and 2" or so bore.

John

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One thing I missed on this is the 100mm dia bar, maybe because cms were used. That's too big for the chucks that normally come with a southbend. The best bet for holding it would be the 4 jaw with the jaws reversed but even that is a bit risky without more support. The 4 jaw will hold work far more securely than the 3 jaw.

The best way to do it would be to use the fixed steady. Chuck the work, set the steady and face and centre drill the end. Remove the steady fit the centre and skim up the work right back to the chuck, just a light cut. Set the steady again, it now has a surface that is running true, leaving enough space to make the 2 smaller ones. Drill and bore, turn the od and part them off. Same with the larger ones but you will finish up with the steady rather close to the chuck. Maybe closer than it can get, you'll have to check. In that case you should be ok parting off the last one without the steady as the projection will be low.

When mounting it in the 4 jaw adjust the jaws to get it running as near true as you can not forgetting to tap the far end to get that running as true as the part in the chuck. Final adjustment if needed to get something very true is done while fully tightening the chuck. If that doesn't work out go back to adjusting the jaws. It takes a bit of practice.

I might have ordered up suitable slices of material but if the faces needed to be rather parallel an expanding mandrel would have to be made as well. Not easy with bores this large.

LOL this assumes that the bar is long enough of course which unless the measurements are messed up it isn't even if no material is wasted making them, 4 x15mm = 60mm which is > 40mm It's probably big enough to make 1 without any parting off unless the faces need to be parallel. The o/d could be turned by doing half and then reversing the work in the chuck and doing the other half, Bore and then part off and finish the thicknesses individually. They faces could be trued up to the bore and made parallel but that would need an expanding mandrel - easy to make for small bores but not for ones of this size.

John

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2.5mm too weak for parting off ?????????

Words fail me especially as i often use a blade 1/16 thick. The thickest one I ever use is 3/32 thick

One thing I forgot to mention about parting off that will cause problems. The blade must be square to the axis of the lathe. I do that by using the face of the chuck that is holding the work.

I am assuming that the OP does have a parting off tool because grinding one from a tool bit to go to a depth of 20mm wont be easy but could be done but I would be looking for some 5/8 thick tool bits ideally or 1/2in - the same depth as fit in Myford sized parting off blade holders. Actually Southbend tooling is likely to be deeper. My Boxford sadly has a Myford branded tool post on it. They fit the same holders as on their other lathes even though there is more height available.

John

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Edited By John W1 on 21/07/2015 22:51:04

24kg sounds like the baby lathe range to me. I advised a friend to not buy one but he did. Some months later he said he wasn't sure what it was for maybe turning plastic. He chose the lathe over the mini range on the basis of it's weight. Having some idea of what he wanted to do I thought that the mini lathes were marginal.

John

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I would just make the smaller bore ones first parting the 2 off and then the larger ones finally parting each off. I don't think I would bother trepaning the 45mm out just turn the 100mm to the right size for a distance a bit over twice the spacer thickness plus twice the parting off tool thickness. After all it is a southbend, it wont take long to get down to 45mm dia from 100.

Making and parting off the smaller ones first means that the depth of hole drilled and bored wont matter.

The problem people usually have parting off is going too gently / slides too loose / tool blunt / above centre / loose headstock bearings. Some sense has to be used in respect to too gently but often if the rest of the lathe is ok speeding up the feed a touch will get rid of the horrible chattering noise that some times happens. If it doesn't it's a case of carrying on. If for one reason or the other there are chatter marks on one face on jobs like this make them a bit thicker, grip on the outside of the 3 jaw jaws and face them. If the lathe is normally noisy parting off better finish will usually be obtained facing from the centre out and in other cases too. Sometimes with the cutting edge of the tool only at a slight angle to the work - this increases the size of the cut even when fine ones are taken - bigger cuts take more of the play in the machine out.

On a southbend the most probably cause of any problems will be the headstock bearings if the slides are slightly on the tight side. Unlike a Myford of rear parting off fame to try and get round it the lathe's bed is very unlikely to have anything to do with it..

John

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Looking around on the web some people use petrol lighter wicks on Lister engines. 2 off them together might work out on a Pultra. It seems that they are 2mm dia. There was also a suggestion that the flow can be regulated by binding them more tightly, fine copper wire maybe.

My 17/50 has seen a lot if use in anger. An owner made new bearings for it in 1995 and reckoned they lasted around 15 years. The lathe was new in 1947 and the next and last owner used it daily for a long time. The bearing seem to be still fine. From the way the oil reservoirs empty I can see that there is a wick fitted to the front bearing but not the rear. I assume that's been done to prevent oil from causing too much belt slip. I need to make a new pulley for the headstock so will see if I can build in some sort of oil slinger but there isn't much space. On the other hand I suspect that the person who made the bearings knew what he was doing so none in the back might be common.

John

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Thanks Dave. It's more reassuring really that it should come off in that direction.

I had slackened off the rear nut, pushed the spindle forwards to create clearance between the sleeve and the rear bearing and expected to be able to push the sleeve back along the spindle. It's stuck and wont move at all with finger pressure so I wondered if something else had to be done. Sounds like it just needs a bit of forces to free it.

It's a pity no one seems to have the "words".

The ebay pultra I mentioned never reached the end of the auction. Bid's cancelled and marked no longer available. I suppose the seller had an offer that they thought they couldn't refuse. Pity really I was very curious to see how much some one would bid on it. I contacted the seller as the listing showed the same headstock drawing but it seems they didn't have the words either.

Next problem for me is just where do I find some oil wicks. Looks like they need to be around 0.1" dia. Perhaps a bit bigger to ensure they stay in.

John

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If you have ever used a 10in industrial off hand grinder some where that have also bothered to sort out the correct grade of wheel you would think size does matter Bazyle.

The answer I have found to work fairly well is the 6in aluminium oxide wheels the Axminster sell. They wont grind super quickly but the main reason that they handle HSS well and even Tantung G is that they are probably a bit more friable than what would generally be thought ideal for tool bits so they cut slower than an ideal 10in wheel but coolly.

I recently bought a 6in FERM grinder, same as the Record one but a lot cheaper for the wide wheel. The FERM ones are on amazon, some one on ebay was trying to sell them at near Record prices. They have the usual wobbly wheels problem probably due to the flange washers. I'm wondering if there is some way I could increase the size of the hole in the wider one that comes with it. as a replacement to put on something else would cost more than the grinder.

John

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