Member postings for Ajohnw

I use one for all sorts of things and don't wear gloves as I feel that protective ones would be more of a hindrance than help. The main thing is to keep the guard in the correct place and to realise which way the sparks will fly because that is the way and chips from a broken wheel will fly as well. I've never had a wheel break even on a hefty one Makita designed for fettling castings. Sounds silly but the position of the guard can need a bit of thought before applying them to anything. If you are using a wheel that grinds on the flat side they also pull at little - they are powerful tools.

Eye protection and possible a dust mask are the main things really plus thought about how it will be applied to the work which can mean changing the guard position from time to time.

John

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Silly me. For some reason I read the width as the thread size. They are a little narrower than the full 16mm types though.

John

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Is the width of the bottom of the ARC T Nuts correct on the 10mm slot one? 12.8mm seems rather narrow = 1.4mm per side. It aught to be 16mm going on some others I have seen.

John

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I have the problem of buying a retired toolmakers dore westbury. He made just about everything himself. I've managed with this type so far and I can understand why he made them - they can be rather expensive to buy. They are heat treated, 3/8 thick and 3in long. There is also some smaller stuff.

As these work rather well I didn't really want to buy a set but the prices buying bits and pieces work out far more. He made a number of clamping bits and pieces for it but the studs are a bit of a mess. I could fix that via high tensile all thread. For some reason he settled on 5/16 bsf for studs. The T slots may be metric, M8 I suspect but M6 is available in the same size of T. I'd guess he had something else about and 5/16 fitted both. It's easy to make T nuts, a strip at a time and then saw them off.

The reason I wondered about setting the height on the step blocks and the angle range of the stepped clamp is that I did use the blocks briefly and from memory the steps are angled so that they pull together rather than slide apart. I assume the clamps with the steps on the end are the same so past some angle they wont pull together. When the clamp isn't level spherical washers should be fitted as well but I suppose that's really only needed for rather powerful millers but suspect I might get some of those.

T nuts are sold threaded all or part way through but at a couple of quid plus each where I have seen both styles offered I don't think I will be buying any,

John

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The only problem I could see is the limited angle range to keep the steps locked together with no chance of slipping.

Neil makes a point though. The one is the shot are 25mm wide - how wide are the arc ones? I would be looking for M8 - m10 slot for my dore westbury.

John

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Every time I mill something with clamps I have mixed feelings about the clamps I have. I really should get some step blocks but while looking around I saw these clamp plates that can be used directly on a step block.

Any one tried them? I'm happy the blocks with normal clamps are ok so can't see why these wouldn't work out.

John

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I have bought Burnerd chuck spares of these people in the past

**LINK**

They also sell a range of chuck jaws that can be found on the site.

John

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Why not make a rotary table ? The difficult part the worm and wheel can be bought. The gashed ones intended for model engineering projects - that's effectively a gear with the teeth at the worm's lead angle. It's also possible to use a gear with the worm at an angle.

The best trick for worm and wheel engagement is to mount the worm in an eccentric but some designs swing it into engagement sometimes in a worm carrier. College Engineering used to do a pretty hefty 5in kit. It suffered a bit when it was Myfordised to fit in the gap but was still pretty good. Better when it was intended to be made on a Boxford.

Castings were widely available but seem to be thin on the ground now. A stick welder and plate steel can be used to solve that problem or machine from solid or even a mix of the two.

John

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I stick to these as they are the nearest thing to a sharp indexable tip that I am aware of

That's an 11mm tip fitted to what may be a 9mm tip holder. The 11's seem to be a bit short of that and the 9 a little bigger. 16mm is also available.

This is the same general shape I usually use on HSS because it will turn both ways even though there is negative rake in one direction and it will face and face plus relieve shoulders as well. The rake is positive in both directions on the tips. The only problem is this style of holder which only seem to be available in cheap kits with several shapes in them so at some point I need to make one myself. The tips in these kits aren't bad. They look like general purpose to me but don't have this degree of rake. Some of the kits use hex socket screws to hold the tip - best change them to torx before the keys wear out.

Boring bars are also available that take the same inserts. Only problem with the one I bought is that the picture showed a tip angle suitable for boring blind holes and lightly facing the end. It turned out to be angled for through holes so when needed I will have to modify it. Thanks RGD.

If people are into different profiles for different materials they are pretty economic. 2 will do. One micro polished for aluminium and none ferrous and another for harder stuff, stainless etc. The reference numbers for them can be found on APT Carbide but there is need to look at the actual page for a tip to see what it's suitable for. The one in the shot is for stainless and alloy steels and also works well on brass. The aluminium tips might be better. I didn't have any last time I worked on brass.

To be honest though I am not convinced that they are any better than a highly polished decent grade of HSS. The problem with HSS is getting the polish and also the small rad. A slip stone helps a lot and can also be used to sharpen the tool while it's on the lathe.

John

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CVA's can come in pairs

**LINK**

John

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I would suggest that the NVR's will fail over a much shorter time period than a dewhurst switch. I've had several lathes with them on and not one failure. My mill has only seen hobby use and not much at that - the nvr has failed. An industrial one as well.

John

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I use a tool something like this but cutting tool length and narrower with and increased angle on the end so that the point can be plunged into the work.

it can be used to "face and bore" through material. I've not tried it on anything of your size but it's what I would use.

Looking at the shot you posted I think I can see signs of the tool rubbing on the outer edge. You need a rad on that side of the tool that is smaller than the diameter of the hole you will be left with.

John

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The reason he uses a long plain hole is down to precision and the ease of making adapters.

Collets sound great but SHOULD be specified for run out 50mm from the opening. The advantage of the long hole is that it's all set by the length of the part in it and the clearance. The clearance can be very small. It's pretty astute of him actually and aimed at model engineers working at home and making most things themselves rather than buying and not just using it for gears. If I remember correctly he mentions considering it.

Personally I would add a spindle nose to it. Mine has a Myford nose and I use a boxford so I have a 3 morse to myford adapter and a draw bar for it. It also has a 2 morse socket which basically means I would have to make taper adapter or buy and hope they are decent quality.

As Rod mentions you could buy a straight shank er25 collet holder. They are available with a 3/4" shank also 25mm or 1" but they always seem to be undersized. Or even put an ER on the end but I would still retain an accurate hole behind it.

John

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The nvr switch on my miller had starting to act up so I bought one of these which are nice and compact.

**LINK**

I've also used them on machines that I no loner own.

John

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Yes Dewhurst switches are from another ear - built to last. They do too but like most things how ever well they are built can wear out.

John

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The ones IanT shows in his photo are fine - ebay etc. There is another type that has a sort of plastic latching part that fits over the off button. Personally I am not to keen on those even though they may be cheaper. They are irritating to use as an on off button as the latching part gets in the way.

John

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Edited By John W1 on 13/08/2015 12:29:53

I've found a standard that seems to work in wood and with a bit of care in tight raw plugs fixed very firmly- buy screws from Wicks and screwdirvers from b&q, the black and yellow handled ones - if that is still the colour they use.

John

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The bed on the 7k one looks rough to me. Not so the 3k one but the ground out bits are odd.

Not encouraging any one to buy but ..............

It's pretty easy to check out lathes like these. Gear heads hardly make any noise at all in fact the motor will make a lot more noise under heavier loads. A hefty piece of fc ms is needed to check the rest out. The diameter needs to be as big as the chuck will take and grip firmly. The sizes look a bit small for the lathe to me on both of them but I'd hope they would take 1 1/2 or better still 2in with 4 or 5in sticking out. It's best to take a decent tool along too. Some dealers will provide a rubbish tool so that people will think that they can do better at home and not even bother to set it up. Apart from taking the skin off bright drawn if the bearings are in at least reasonable condition a cut of around 0.040" should give a decent smooth even bright finish with a moderate feed, not too fine. If a taper is measured afterwards or the tool recuts when it's wound back the bearings are loose/not too good or the bar has bent. If a heavier cut say twice this does give a decent finish the bearings are all most certainly to blame but some lathes are a lot better if the cross slide is set up with a bit of friction rather than being loose. If the bearings are in incredible condition and the lathe has warmed up very light cuts can be taken but vibrations might leave faint marks. The usual sign of slightly worn bearings at reasonable cut levels is rings appearing along the work as it's turned. Increasing the cut will usually get rid of these. It's cause by the cut just holding everything in place and minor variations in the hardness of the material.

I'm not sure what HP these lathes have but I'd guess it's up around DSG levels. They will take 0.250 cuts with a 1/64 per rev feed on bar around the 4 to 5in dia with ease even breaking up or compacting the swarf with a breaker on the tool fast enough to produce blue swarf. That's 1/2in off the diameter in mild steel. This wont do the bearings much good though. From what I have seen of tool room lathes the bearings are shot a long time before the gear heads get noisy or the bed is badly worn. Tool rooms don't ask much of lathes usually as most things made get hardened and ground. Some might have a little used machine about for if needed. When lathes will no longer do what they want they get rid of them and the dealers pay pea nuts for them.

Another factor on lathes of this sort of size and design is that after they have been running for say 20min the head stock will get fairly warm especially at the front. Most will improve when they have warmed up if they have a little or no wear.

Checking out a small lathe is a lot more difficult. The bar is bound to bend.

Chuck size - where I was trained each lathe had a wooden block with it that the chuck could be dropped on without damaging the bed. The blocks also more or less lined up the chuck and were only a few inches thick - the chucks were very heavy too so the blocks were much appreciated. No such luck in tool rooms. Maybe this and cost is why they are often fitted with chucks that look undersized to me.

My training makes me laugh some times. They even had me turning up go - no go plug gauges to insane tolerances for a lathe really and with the right lathe and a well ground tool it's very difficult to tell that they didn't come off a grinder. Trouble is no one does that in the real world any more but if used intelligently and the lathe is up to it it's possible to work to 0.0001in reliably - over short distances at least.

John

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What did you replace it with John? In excellent condition - more or less as new it's the only lathe I know of which is as good as DSG in the same condition in terms of accuracy and finish. Colchesters are the pits in comparison. Curiously Students can be good - for a while but the bearings soon act up if they do a lot of work.

The model I am familiar with would be older than the ones in the links. It was very definitely based on a spinning lathe bed. It was fully kitted out including gears for dp, module, imperials and metric complete with screw cutting indicator with a gearbox in it. Screw cutting charts for all of them too via a gearbox. My recollection is that the head was bigger than these. As I mention the gap bed was huge. Typical of spinning lathes. I saw a CVA spinning lathe produce a commercial sized "saucepan" around 2ft dia at Bullpits by hand and was offered another blank and a go afterwards. I've always wished i had accepted the offer.

I listened to my fathers wisdom in the end when I found a suitable one. When at school he asked me what lathes they had in the metal work shop - Boxford. He said they aren't bad, pretty good for a small lathe really and based on Southbends. All I ever made on the smaller none screw cutting one at school was a few brass cannons that fired wax crayons powered by match heads. One thing he was very firm on is that Colchester forced other companies to make better lathes - his way of putting it was that they sorted them out but he also pointed out that lathes vary even the same type from the same manufacturer. I'd guess that is down to tolerance variations who ever makes them. He also once went to Myford for a demo when looking for several small lathes. His comments about that were interesting.

John

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Imagine the gentle hum of the gears and an amazing finish and that just about sums these up - if it's as it should be. All from what is actually a smaller machine even if it does weigh 1.5 tonne. They did one with a gap bed too and what a gap it had. Actually I suspect that one had a bigger head stock but was still relatively short.

My fathers speciality was metal removal in the automotive field - what and how etc. These were his favourite lathes. Part of that would be down to their floor space. The other would be quality. Some automotive companies often had requests for older parts that were no longer made and this is what they used to make bits for them. When my lathe size at home increased and he had retired he said he wished I had mentioned it while he was working - he would have sorted out a good one for me. I never gained his opinion on millers. Pity really.

John

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