Member postings for Ajohnw

I have read in rather old books that chuck weight is a major cause of bearing wear. I think it is a fallacy. Cutting forces have a much greater effect. I did have an ML7 with 125mm chucks and know from reconditioning the head stock bearings that there was hardly any wear at all in the lower bearing halves that could be caused by chuck weight.

I think the concern from the manufacturers end is size of work and torque but all that I am aware of offer a small chuck that may come as standard and a larger one at extra cost. That includes Boxford. I have the original 100mm chuck that came with my ME10, also a 125mm one that some one has fitted themselves. I am looking at fitting a 200mm 3 jaw to it. That will have a very significant effect on chuck weight due to the piR^2 relationship plus other factors relating to strength/size of parts and maybe their should be some concern about weight with a jump like that. Chucks of that size are only usually fitted to very hefty lathes - I wouldn't include the modern boxford in that range. Those do look like they would take a much bigger chuck than they are usually fitted with. A lot of modern lathes are like that. I'd guess that they largely base the chuck size and fitting on the bore of the spindle and that's about it really.

4 jaw independents are generally bigger than the 3 jaw supplied with the lathe, 200mm on a Boxford for instance but they are much lighter chucks.

John

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Thanks Jason. I just look at the pictures. So I could have one extra tip to wear out. However I mostly use a tool with the V pointing forwards. I did look at the diamond shaped ones with only 2 tips but went for the 3. The only problem is I don't seem to be able to buy a substantial holder that holds the tip like this

That's one out of the cheap sets that Chronos and others do - 10mm / 3/8". Not that the lack of a hefty holder matter really. Actually I posted a link to some one selling these holders along with the raked tips fitted. They usually have the ones with a groove round the edge on them. They will turn both ways and dig in if needed. Same in HSS even though the rake will be -ve in one direction. I only grind straight bar turning tools if I feel lazy and need a new tool. It takes a lot longer to grind the V without over heating.

One problem on a wabeco so could be the same on a mini lathe - when I orientated it to face the cross slide didn't have enough travel. The tool was about 25mm short of centre. Ok for normal turning but I may need a specific tool for facing - which I have.

When I ordered 2 holders off APT one turned out to be the wrong type. It takes the diamond type. They sent me the right one so I will probably modify the wrong one to gain a holder like the above.

John

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It would take some effort to switch me off TCGT 11's now. I don't like square inserts. There are plenty of cheap holders about for 11mm triangular inserts. More substantial holders for them are reasonably priced too - if bought from the right place. Some people go for the 16mm tips. I think 9mm is available as well.

I have used DCMT's in the past and still have a couple of holders for them and tips. One box of tips and holder is yet to emerge. The box of tips that have now been put in the right place is so old and tattered it's hard to read what they are. Something like DCMT 312 512 -11M. The first 2 1's in that might be something else. Sandvic coromant. Bought when Graham Engineering of Alpine brand fame were alive and well in West Brom along with a large show room.

Personally I feel micro polished is a very good idea if aluminium is being turned. Some of the tips Neil mentioned are available in that state also raked but I find square tips a pain when working up to a shoulder. I'd rather square it off and finish it with the same tool.

John

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The Hobymat are still available under a different name and as lathes go not that bad really based on the one I had. I assume they are still as well made as they were

**LINK**

Catches

The next owner of mine over tightened a tool in the tool post they used to fit which clamped down directly onto the compound slide. It cracked the casting. They seem to have changed that.

If I did a lot of screw cutting I had to dismantle the dog clutch and clean it up with a file. I was screw cutting HSS though as used reamers were a cheap source of blank MT1 arbours

People sometime mess them up by adjusting the saddle fit due to not understanding how this works. Taken too far this can even wreck the lead screw nut. Mine was used by one owner for a few years and did need slides and saddle fit adjusting a touch when I bought it but I am a bit fastidious in that respect as I think it pays long term. It was usable as it came.The results it gave where excellent and in it's way a nice machine to use.

Price - well if you want what should be quality even in the hidden places unfortunately it has to be paid for.

I'm not suggesting Brian changes just answering comments like rubbish etc. Brian might not like the weight anyway. Personally I feel the lathe he is using suffers because of that aspect - exposed lead screws and short slides, probably hidden bits of the bed machined away. There will be other aspects as well. Fix this sort of thing and weight will go up. Fix the lot and I doubt if it would compete with the renamed Hobbymat. I'd tend to favour this one over Taig and Shereline but have never used a Shereline so can't comment really. Plus I have no idea if they are now as good as they were.

John

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I used to have the flying chip problem on a Myford Mark. ML7 I put it down to loose headstock bearings and that proved to be true. It didn't much matter what sort of tool I used. i recently bought a used Wabeco that seems to have a slight chip breaking feature built in. Not sure what needs adjusting yet. The lathe is covered in rather short bits and the owner used DCMT's similar to Mark's. I tried the tips I use and had similar results but the finish on ms was marginally better.

You could always upgrade to the latest tip in that sort of line Mark

**LINK**

Even turn carbide then.

For interest here is the tip Mark is using

**LINK**

Some don't have the serrations. Chip breaking depends on feed rate as mentioned.

John

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I'd forget trying to dowel the gibs Brian. Way too easy to mess up. The gib strip should have some dimples in it that the adjustment screws go into. These support it vertically and keep it in place horizontally.

So if you slacken them a touch and move the gib around some how you should be able to feel that the screws are in the dimples. Slacken them more and it might even be possible to push it out. I do have a baby lathe compound slide and there is plenty of clearance taken up with the screws, way more than my boxford.

The tops and bottoms of the gibs are usually angled so that they are horizontal when in place so if you do take it out make sure you put it back in the right way around. They are angled on the compound slide I have and it also has dimples. Sieg I suspect as it came from arc. The lead screw location isn't good enough for what I wanted it for which is why I suggested locking yours when it's not in use.

We all need to boldly go where we have never been before at times Brian. It's not rocket science more a matter of confidence.

John

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Edited By John W1 on 06/10/2015 11:59:36

I can't say that I agree with that Clive. They have moved on from the initial flat inserts and also the ones with rake obtained with a small groove along the cutting edge. In part the changes reduce cutting forces = less HP and then micro polishing for aluminium so that there is less trouble with the stuff melting and sticking to the tip. Then there are ones for milling designed for high feed rates. On the milling side I have noticed that many of the used cutters sold on ebay use old obscure inserts. Many of them are fine, some damaged. I decided to order something relatively modern and versatile from Hong Kong. It also comes with a lot of tips - in some ways I would rather have picked my own because I have gained the impression that micro polished are the best option for home use. Mainly from what they state they can be used for. As I see it a tip which is basically intended for aluminium but can be used for finishing stainless should be suitable for just about everything.

Chip breakers are another factor that for me don't seem to work that well on these tips. This could be down to both speed/feed and or size of cut

High speed - red hot swarf. I find that hard to accept unless oil mist or coolant etc are used. I have seen large cnc machines machining aluminium. There are several reasons why I wont be able to do the same thing at home or achieve the same finish they do. One is speed, the other is rigidity which has a large effect on finish. Cooling too. My boxford is not exactly a light weight machine. The bearing in the head stock are most definitely not suited to cnc machine speeds. Having seen these machines being set up things aren't a lot different to using a lathe really. The speeds and feeds needed are often determined by the part that is being made on them not manufacturers tables. Tip choice - same. The company I worked for spent just short of £2M on a few of them. 3 if I remember correctly. They went to India some years ago. Company policy - hardly any labour content in the UK at all. One setter part time. A few people to palletise the parts then assemble. I'd guess that they are now being made in Germany. Moan over.

John

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Edited By John W1 on 06/10/2015 11:41:07

They do wear over time Brian but this seems to be a bit quick. Are you sure that the adjustment screws are in the dimples on the gib strips ?

There is a chance that use will wear machining marks on the slides fairly quickly which is why I usually mention lapping new machines. This is best done with the lead screw out and is described on the Oz Taig site for preparing a machine. Even though the finish on those is good it does improve them. They suggest using some sort of kitchen abrasive/cleaner that is sold in Oz. In the UK I use CIF which is a cream that women reckon doesn't scratch. It's just impossible to tell them that it's slowly wearing surfaces away. The best way to adjust is to do it with the lead screws out as well as it's much easier to judge the amount of drag pushing the slide by hand.

It's often easy to remove the cross slide lead screw on many lathes. They are fastened the same way as your compound slide is. Looks like you would have to remove the handle and slide the whole cross slide off away from the handle and then unscrew the lead screw.

What I do to set them up without removing it is get an idea what the handle feels like when the slide is moving easily. Then position the slide so that the entire length if the gib strip is in contact with the dovetail and tighten all screws firmly. Then back them off and adjust so that they are touching the gib strip and lock them in place and see what that feels like at the handle. There just needs to be a very slight increase in drag from when it was loose. Usually the screws need unlocking and tiny adjustments made but once it's been done a few times it's possible to get an idea just how firmly the screws need to touch the gib strips. I've mostly adjusted used lathes and they generally need several adjustments over time as things settle down. On one lathe there was too much wear to allow them to be set correctly so a compromise has to be used. On my Boxford I accept that the cross slide will be a bit tight when wound fully out. As it's a long slide I could slacken the outermost screw off a touch but I prefer to leave it as is. Some lathes don't benefit much from being adjusted like this but I find smaller ones generally do especially if light cuts have to be taken. Heavier cuts tend to push things firmly home and keep them there. I was stuck on a rather large Lang during training. They had left the slides loose on purpose and the finish was awful and improved dramatically when adjusted, the best I have ever seen. They did this because this is how tool room lathes are often set up. An extreme example. The idea is to reduce lead screw and nut wear and just wear the male dovetail at the corners so that they can then be adjusted correctly if needed. Trouble is that at some point they wont adjust correctly as the whole face of the dovetail develops a taper.

A number of people have found that it is best to buy some slideway oil and use that as well. All I'll add to that is ain't t weird that something that is sold for a specific purpose works better than some alternatives - or is it? I have used motor oil including synthetic etc in the past. I even tried EP gear oil once but the smell put me right off.

John

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While tidying up this has surfaced again. It's the lever operated type with a max capacity of 1in.

Problem - I lack the installation instructions can any one help?

For some of the chucks they give dimensions for where the pivot on the end of the lever needs to be located. I've not had much luck finding anything on this model which is the one Myford usually supplied. I need to mount it on a Boxford though so the attachment Myford provided for the lever to operate against wouldn't be of much use. Boxford appear to have used something which is held in place by 2 screws on the lower front face of the headstock so the lever would have been vertical. Other lathes used an attachment fastened to the bed and Burnherd provided sufficient info to determine where the pivot point should be. That is what I ideally need for the 1" max chuck.

John

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Boxford did change the bearing types used at some point so the settings might not be appropriate any more. There is some comments on lathes co uk about that. From memory they did use taper rollers that had a lower cone angle and then switched to the standard cone angle ones which are also much cheaper. As far as I know they don't use super precision bearings in the older lathes but still achieve much better run out figures than that. They test to a max error of 0.0004" on the spindle and reports I have seen show 0.0002" measured. Taper on work max of 0.001" per foot, measured 0.0007". Some come out better. The taper can be corrected by straining the bed but that needs a substantial base for the lathe to sit on. Mine shows figures that are much better than this so I'd guess that the bearings do run in a bit.

I assume that the torque was measured without the spindle driving any gears ?

Bearing heat should still be an indication on a gear head lathe really. There will be some friction when they are running correctly. My reason for doing this goes back to training. Much bigger lathes but it was pointed out that lathe bearings ( gear heads) run at over 100C. Easily noticeable by touching the head stock around the bearing housing. They get very warm. A number of the machines will have had 2 angular contact or roller bearings fairly close together at the front so more sources of heat in that area. Anyway after going through the exercise of adjusting them I can now tell when the lathe has warmed up. Very very light cuts show marks on the finish which are caused by a wobble on a counter shaft pulley. The repeat pattern it generates can be seen on this

Only a few micron deep but irritating. The shot is larger than life and the finish feels glass smooth.

Machine the spindle - no way. If needed make new chuck back plates as machining the register on them will have the same effect. In fact they may have already had that done. It is possible to true up morse tapers with a reamer but DO make sure the tail stock one is correct first. That can still be trued up in the same way even if there is a slight error in the spindle. This should only be done after it's been set as accurately as possible via it's adjustments and shimming if needed and is only intended to remove a few thou not correct gross errors. The only sensible way of checking between centre alignment is via turning tests or the use of a test mandrel and dti and even then it's possible to miss interpret the results. Parallel between centre test mandrels don't seem to be available and the ones with a morse taper on the end usually have a hole in the end to take a draw bar, not much use really.

The usual way of truing up a tail stock morse taper is to fit the reamer in the 3 jaw and push the tail stock up against it with the quill part wound out. It can only be done if morse fitting still have some taper sticking out when fitted. This assumes a well fitted 3 jaw chuck.

I think the OP would best do some heavy turning with the machine and then check things again. There are also some simple turning tests that can be done to check the alignment of the spindle to the bed but bed wear can mess these up a bit. Excessive recutting with a tool at the same setting is a good indication of loose bearings. If very bad the same setting will take several noticeable cuts.

One thing most important on lathes - don't jump in. Make sure of what the problems really are before attempting any corrections otherwise things will probably get worse.

John

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Edited By John W1 on 05/10/2015 17:10:46

Putting too much grease in the bearings can mess up the Boxford settings. It should just be enough to lightly coat the parts of the bearing.

When I've tried it the initial reading due to spinning the parts up even as slow as that is needs to be ignored and the readings taken when things have settled down hence 4ft of rope or what ever. I also think the machine has to be run to distribute the grease but there is a catch in that. The bearings will warm up and tighten so need to be left to cool down again. That will take some time.

This subject crops up on the yahoo boxford site at times and many including me have found that the pre load is too low. Easy to tell because if a decent sized cut is taken on a rigid piece of steel it will take another cut without any change of setting - more than what might be due to the work bending. The problem can be down to wear in bearings as they are bound to wear oval over time as the forces on the outer shell are always the same when the lathe is cutting material.

What I did in the end was to use bearing heat by feeling the area under the rear bearing via a finger in the end of the spindle. I'd run the lathe for at least 15min at 500 rpm or so and then check for definite warmth - not hot but very warm. It would be best to then do the same thing with it running flat out as a check.

It's worked for me and I just have a tiny recut that I think is down to bearing wear but I haven't changed the bearings yet. I had the spindle out but the front bearing inner is way to tight for me to remove and replace at home. It really needs a bearing press and probably a heater as well.

When I bought the lathe initially I found that the bearings loosened each time I drilled a 1in hole or did some heavier turning. This must have been because they were not seated correctly. Not that uncommon a problem.

John

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Cast iron varies Brian so not an easy question to answer. If it happens to be a bad sand casting the skin will destroy hss quickly. I doubt if stuff supplied to model engineers will be that bad. I've mostly used braised tip carbide tools on it. HSS can work out but may need lower cutting speeds than mild steel.

I haven't turned any for a long time so haven't tried indexable tips on it. When making tooling I've used braised tip carbide. At the time these were always supplied in a cast iron grade. They may well still be and have relatively low angles to avoid chipping.

John

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I did buy what ever of ebay but found that some didn't last as long as they should so am pretty sure that they were used and had been on cnc machines being used for production work where they are removed before performance drops off. Actually I saw a whole bucket full of tips like this at a dealers who was thinking about selling them. He invited me to look at them with an eye glass and no problems could be seen but the coating will have been part worn out.

Following suggestions from some one else I tried TCGT types. These are representative of the latest ideas on inserts. The form on the top of the insert is changed to provide a sharper cutting edge with rake. I went for 11mm ones as they fit holders such as these

**LINK**

Those are actually fitted with this style of tip and even come with torx screws. Mine had something else on them and used hex keys which are hopeless, the key soon rounds over. 16mm tips and holders are also available. The triangular shape is good because they can be used up to a shoulder even for facing it. I think 9mm are also available. I've since bought a proper holder but can't find one with the V pointing forwards so will have to stick with the 10mm ones or make one myself.

I feel that these tips do compete with HSS but I haven't tried highly polished HSS with more extreme rakes - yet. The performance drops of when the coating wears off but there are versions about that are polished and have no coating at all. These are mainly aimed at none ferrous and abrasive materials but some are also suitable for finishing stainless so I will be trying these on all materials at some point. I have used coated finishing tips for stainless as these were what I originally bought. They work well on ms, silver steel, brass and al. Al is probably the stuff that tends to wear the coating off.

I had hoped that I would be able to find a face mill that used the same tips. No luck but it looks like APMT1604/APGT1604/APKT can all be used on the same holders so there is plenty of scope for tip geometry including micro polished. These can also be used on rather large end mills. Smaller sizes use smaller tips. This is one of the problems with the technology as I see it so it pays to spend some time determining what shape and size of tips to go for. The volumes sold seem to have a direct bearing on price.

I've decided to try my own theory on face mill size. Cranky - what? Say I buy a 50mm one and run it at some cutting speed. As my miller uses a belt drive the cutting torque available for the same cutting speed would be the same for a 100mm one as it would be running at a reduced speed via the belt. I don't expect to be able to take a large cut with either size. I've no idea how deep a cut I will be able to take.

John

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It's a bit weird that they only list AK10 ground and polished now for aluminium ??????? I think things have moved on.

John

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Books wont be much good for inserts as they keep evolving so have little chance of keeping up to date.

John

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What about these

**LINK**

2 5 star reviews which for some reason aren't showing.

They give the side clearance but the base of the tip would be square to the cut in their normal holders. From what I have seen the recesses in the tool are sized to fit the base of the insert so are always a bit smaller than the nominal size.

These show why I have been wondering about using this style of tip for everything but 11mm on my lathe - extended use = finishing stainless. The first tips I bought of this style also mentioned finishing stainless but no mention of aluminium. They give a better finish than the tips that come on the cheap holders on all of the materials I have tried them on, crap silver steel, FC stainless, al and brass of various sorts.

I also bought 2 of there own brand TC 11mm tip turning tool holders. They come with a key and screw and are very well made plus a lot cheaper than some.

John

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Edited By John W1 on 04/10/2015 23:23:22

I have mixed feelings about oil and chuck fittings as it can increase the force they retain at rather a lot. If your getting mixed readings it might be worth putting some slideway oil on the pins. It's a heavy chuck and you might not be applying enough force to pull the chuck really home. Oil will help with that.

When I was working on lathes with big chucks they always had a wooden block that fitted on the bed and also aligned the chuck effectively taking it's weight so all the locking mechanism had to do was pull the chuck in. I've been thinking along those lines of late as I have just bought a monstrous 200mm chuck. The increase in weight over the 125mm grip true normally fitted is pretty dramatic.

John

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I've been wondering if I can get away with a 100mm one on a relatively low powered machine. The idea mainly being to use it for finishing. Belt drive and I think a 3/4hp motor - the rating has worn off the plate but it looks too big for 1/2 hp.

For 40 - 50mm cutters I've sort of concluded that APT economy range with inserts are more or less as well priced as others unless they are bought from the far east. No arbours with them though but no odd inserts either..

**LINK**

What I would like to get is a large face mill and a few end mills all taking the same inserts.

I'm not on commission etc from them but what ever I order comes next day and no problems at all.

John

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Edited By John W1 on 04/10/2015 20:36:20

Edited By John W1 on 04/10/2015 20:37:05

I'll probably make the delux version. What I usually do is place some packing behind the work and press it firmly home while tightening the chuck then pull the packing out which might be a parallel strip if I have something suitable or what ever i have to hand if not.

John

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I would have thought that if the chuck is mounted on a back plate it's more likely to be that than the actual chuck. By backplate I don't mean the fitting on the lathe - any plate actually attached to the chuck itself.

It might pay to chuck something, face and centre drill it and engage a running centre fairly forcibly and see if the run out changes just to rule out other possible causes.

Personally I don't remachine face plates. If made correctly they will be pretty flat were as a lathe will generally face concave by some amount that can vary a lot in some cases.

John

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