Member postings for mgnbuk

The timken designs are great, although these days most people would use fit and forget grease in the bearings of a hobby lathe, not a pumped oil supply - saves on making those labyrinth seals as well!

Not just hobby lathes on the "greased for life" spindle bearings these days - we had a Gildemeister CTX400 slant bed CNC lathe at work that had a spindle bearing arrangement similar to the SKF drawing above that was greased for life.

Why would it be a chore to make suitable labyrinth seals ? Not a difficult turning job & most do double duty as bearing retainers as well. Big plus with labyrinths over rubber seals is the lack of both drag & wear - a grease lubed rubber shaft seal will get hot & increase drag until it wears (and/or cuts a groove in the spindle), at which point it is no more than a labyrinth seal anyway. And some sort of seal is desirable to prevent coolant & swarf contamination of the bearing lubricant - grease or oil.

Nigel B

This is where I got the idea for that ball bearing

Those roller bearings "NN" have a very shallow taper to the inner race bore - they fit to a mating taper on the spindle and, when sufficient force is applied by the locknut, the inner race expands to take out the radial play. The oil port that comes out at the front of the spindle nose leads to a groove - high pressure hydraulic oil (think 10,000 psi + ) is injected here to help get the inner race off at rebuild time . This arrangement is favored by several German builders of heavy duty lathes - sometimes the pre-loaded double angular contact thrust bearing is replaced with standard ball thrust bearings. Very, very expensive in precision grades & can be very hard to find.

Note the labyrinth seal at the spindle nose, with drain hole at the bottom to let coolant out.

As a solution, this is way overkill for a small lathe IMO - opposing taper roller bearings at each end of the spindle as used by Boxford (for example) would be fine. If you cannot turn a spindle with a suitable integral location flange, could you design your headstock around one of the mini-lathe spindles, which appear to be quite cheap as spare parts ?

Nigel B

The company we used to use to regrind beds at my last employment (R Skinner Engineering) did so on planers fitted with grinding heads & used diamond cup wheels. They used special sharpening stones on the wheels - about 12mm square by 100 mm long, white abrasive sticks with an open texture. A bit like a white grinding wheel in stick form, but light weight & quite friable.

Bob had a box full of these sticks & used them sparingly if the wheel wasn't cutting to his satisfaction (which was probably by how it sounded, or how the surface looked). Bob sold his business 10 years or more ago & I have not been in contact since, and I can find no reference to the chap who bought him out, so can't ask directly what these sticks were called. But I would expect that an industrial diamond wheel supplier would know.

On a slightly similar note, I once had problems drilling a floor for holding down bolts using a Hilti rig. The going was extremely slow (I was sent on site to find out why the job was taking so long), so I called in the Hilti rep. His opinion was that the concrete had a large proportion of very hard quartz aggregate & he gave me a "sharpening stone" to regularly dress the core drill when it stopped cutting freely. This was about 300mm square by 25 or so thick & looked like an un-glazed terracota floor tile. It was not very hard & cut easily with the core drill - cutting a couple of 6mm deep grooves was enough to expose fresh diamonds & get the drill cutting again.

HTH

Nigel B

Some time ago I made the mistake of buying a SOBA branded Myford nose mounting ER25 collet chuck from one of the Harrogate exhibitions. I left it too long after purchase to try the thing on the lathe, to find that it didn't fit, to send it back & this thread prompted me to ave another look at it yesterday. lt looks nicely finished, but would not screw fully onto the spindle nose. A couple of hours lapping with fine paste opened up the apparently tapered bore such that it now screws up to the spindle location shoulder without binding. Applying a dial guage to the collet taper shows 0.07mm runout - I guess that I need a toolpost grinder now to true up the collet taper in-situ.

Non of this has any bearing on the original query but, despite the runout, I mounted a ground 12mm pin in a used 12-11 collet (ex industry) using the SOBA supplied closing nut. Runout approx. 20mm from the collet measured 0.15mm. A new Chinese 12-11 collet was tried, with similar results. I had an ex-industry German Zuern closing nut to hand - a bit grubby, but a squirt of brake cleaner got it looking presentable. Using the same Chinese collet & same pin with the Zuern nut gave a runout of 0.075mm - almost identical to the collet bore runout on the chuck. So it would appear that the nut can have a large influence on the gripped tool runout, all other factors being equal. I didn't have anything accurately ground 11mm diameter to hand to see what effect closing the collet down to it's minimum diameter had on runout.

The SOBA nut does not, on the face of it, appear "badly" made, with the main difference being the German nut has a ground thread and collet closing face where the SOBA is just turned & blacked.

Interesting to see in the Regofix catalogue linked to earlier that the range includes 0.5mm increments as well as 1mm - I wonder if the more restricted operating range collets perform better for runout than the "normal" range when closed down ?

Nigel B

If it is a tenth thou (0.0001" resolution Mercer , it may be beyond redemption. In my previous employment I used to use calibrated equipment for checking rebuilt CNC machines & found that the high resolution Mercer guages got sticky and unreliable for no apparent reason. These were cosseted, final inspection only guages, independantly certified & kept in original boxes until required, yet they would not give reliable results after a couple of uses. I cannot recall having had one sucessfully repaired.

I moved to a 0.001 mm resolution Mitutoyo, the independant calibration certificate for which showed 0.001 mm error over it's 1 mm stroke - it may have been better than that, as IIRC there was an uncertainty of measurement given of 0.001 mm. That guage always worked when required - as has every Mitutoyo dial guage I have used.

Nigel B

Update to above post.

By clicking the "having trouble viewing this e-mail - click to view online" tab, I was able to open the "3 for £1" offer from the webpage & signed up. The problem appears to be with the link given in the e-mail.

Nigel B

I signed up for the e-mail Newsletter today & on completion of the formalities received an e-mail with a trial "3 issues for £1" offer for ME or MEW.

Having failed to purchase the current MEW/ME "combo" at 4 different WH Smiths branches, I decided to give MEW another go for 3 months on this trial offer, but the link in the e-mail to the offer does not work. After a couple of minutes waiting, a page headed :

Server Error in '/mymagazineoffers' Application.

Runtime Error

Description: An application error occurred on the server. The current custom error settings for this application prevent the details of the application error from being viewed remotely (for security reasons). It could, however, be viewed by browsers running on the local server machine.

Details: To enable the details of this specific error message to be viewable on remote machines, please create a <customErrors> tag within a "web.config" configuration file located in the root directory of the current web application. This <customErrors> tag should then have its "mode" attribute set to "Off".

and a load of html comes up.

Could this be refered to the relevant MTM department for investigation when they return next week, please ?

Nigel B

If your gib arrangement is actually as drawn, the screws are pushing the gib up an "open" slope - I would have expected to see the screws on the LHS as drawn, pushing the gib into the "closed" dovetail ?

Nigel B

The noisy 'cans' still fail the construction and use for aftermarket exhaust and the MOT should weed them out.

The C & U Regs and what is tested in an MoT are somewhat different. It is possible to get an MoT pass on a bike that doesn't meet C & U - MoT checks you have a speedo fitted if required by age and/or capacity, for example, but doesn't check that it works, which C& U requires & which specifies the required accuracy for the functioning instrument. Same with exhausts - unless it is overtly marked "Not for Road use" or similar, the MoT only checks that an exhaust is securely fitted & not rotted through. It is quite possible to get an MoT without starting the engine & there is no noise meter test. There is a current "fad" in motorcycle customising known as "bobbers" or "brat bikes" - basically strip off most of the legally required bits like mud & chain guards, fit oversize "ballon" tyres, minimalist lights etc. to get a "look". These abominations are frequently sold "with MoT", as the MoT only checks that mud & chain guards, if fitted, are not going to fall off or maim pedestrians. It is C & U that states that mud & chain guards are required to use the vehicle on the road.

C & U infringements require the Police or VOSA (or whatever it's current name is) to get involved.

Which brings us back to the "no modifications" bit - if our MoT was similar to the German TuV test, there would be a specific requirement for Johnny Moped to have a "Certificate of Conformity" for his non-standard exhaust or he would automatically fail the MoT. Same would apply to tampering with the standard or aftermarket exhaust - automatic fail.

2 strokes and no legislation to set what the makers have to do. There should be but the manufacturers probably just said no way. That's how it works.

What a load of tosh ! Sorry to be blunt, but that statement beggars belief.

Vehicle rules & regulations are regularly updated ( a new set come in next year, which will end the life of some models) & manufacturers have to comply if they wish to sell - light motorcycles & scooters are no different to any other vehicle (from electrically assisted bicycles upwards) in this regard and have been for decades.

As supplied, all motorcycles have to meet (increasingly stringent) noise legislation - the "problem" is that anyone can sell an un-approved "not for road use" noise box to the young and gullible, knowing full well that there is insufficient roads policing to apprehend the users of these illegally modified vehicles. And should the antisocial barstewards actually be apprehended, there is no comeback on the sellers of the non-compliant parts who hide behind the "we sell these bits for show bikes only" excuse.

Nigel B

Towbars have had to be "Type Approved" since 2013 IIRC. This hasn't put independant towbar manufacturers out of business, it just means that their products have to be put through a testing process (2 million full rated load stress cycles IIRC) to certify that they are "fit for purpose". Vehicle manufacturers have had to disclose their towbar mounting points for longer - the days of having to drill through the vehicle structure to fit a towbar are very long gone, now it is just a case of pulling the sealing tapes off the pre-prepared fixing points & bolting the type-approved bar straight on. Towbar prices don't seem to have gone through the roof since this requirement was introduced & my insurance didn't increase when I fitted one to my last car.

I have recently fitted an aftermarket screen to my bike - it came with a booklet in all European languages certifying it's suitability and approval details. In German this is the "ABE" - if my bike were registed in Germany, at the time of the TUV test (Mot) I would take this ABE certificate to the test to prove that the "modification" was approved. The same applies to other "modifications" like after market exhausts, luggage systems etc. No problem & not something to get overly worked up about ?

Nigel B

When should Issue 240 have hit the newsagents ?

Mrs B was passing WH Smiths Bradford today & I asked her to get the ME + MEW Neil mentioned earlier. No ME on display - only ME 239. The 2 independants I called at on Friday had neither title.

Nigel B

I considered buying the Chester version of one of these (the Champion) when they first appeared, but after a close inspection at an exhibition decided not to due the design of the head elevation / column arrangement.

With the head elevated as shown in the picture above, there is very little engagement with the column.On the example I looked at, the fit between the head mounting "sleeve" and the column was very slack & the clamping arrangement weak. As the nut for the elevating screw mounts in the top of the column & the screw enters the column when the head is lowered, the column cannot be filled to stiffen it. And that would not address the problem of poor fit between the head "sleeve" and the column, the lack of engagement at higher elevations & the poor clamp. The whole design and execution appeared flimsy and lacking rigidity. Add in that there are only 4 speeds and (IIRC) the lowest was 400 rpm, I decided to pass. That this design disappeared fairly quickly suggests that, despite being cheap at the time, it was no bargain.

The base appears to be a copy of the Emco FB2 design & it may be that this head / column arrangement was added to the FB2 style base to produce a cheaper machine than the 6 speed geared head, keyed column arrangement employed in the original Emco version. Chester also had a 3 speed power table feed for this machine that appears to be a copy of the Emco - I picked one up at a Chester open day & it fitted straight onto the table of my Taiwanese FB2 clone.

I doubt it will be possible to stiffen this arrangement, but it may be possible to replace the round column with one fabricated from, say 200mm square box section steel, with square sections welded on to provide slides & a new "saddle" to mate to the rotating joint on the current head. Not an insignificant project, but not insurmountable either - largely depends on what facilities are available to you.

Sorry to be so negative.

Nigel B.

OK Neil, I'll endeavour to purchase the latest ME / MEW combo package (without an in-store preview) & will provide some "relevant" , up to date, feedback after a cover-to-cover read .

I notice another poster has raised the "staff writer" issue & wondered about the commercial aspects of periodicals publishing. Again, another post in this thread touches on problems being faced by this sector & this got me wondering about MEW / MEW circulation.

MTM helpfully provide some answers - their 2015 "Media pack" gives MEW circulation as 21,000, with a 99% male readership of whom 85% are 50+ and 69 % are retired. The ME "Media Pack" doesn't give a circulation figure for ME (a bit strange in a briefing for potential advertisers), but does say that 99.7% of readers are male, 85% are 55+ and the same 69% are retired. They also say that 84% of readers buy from advertisers and helpfully give a mean income figure and average spend - from which I see I don't spend anywhere near the average ( I'll have to petition the domestic Chancellor for a hobby budget raise !) I guess these figures come from reader surveys ?

The latest UK demographic information I found suggested that (round figures quickly extrapolated from bar charts) in 2014 there were aprpoximately 18 million men between 30 and 79 in the UK, 11 million of whom were between 50 and 79.

So "Model" Engineering would appear to be a hobby practiced almost exclusively by a very (very) small proportion of the middle-aged to old (predominately retired) male population of the UK - visits to ME Exhibitions would tend to confim the age group, but is there really so little home metalworking interest ? Or do current magazines not appeal to a "silent" group of home workshop owners who are put off by the "Model" tag ?

Ii could perhaps be surmised from the above that the long term future for home workshops is not good - after all, the current 50 - 79 demographic is perhaps more likely to have been exposed to more "engineering" than the current generation, and maybe more likely to want to persue this as a hobby than the current generation will when they get to the same age. But, on the other hand, home workshop sized machinery seems to sell strongly on the popular on-line auction site, so maybe the "engineering" interest is there - just not the "model" part ?

I can, given the circulation, see why it may not be practical or economic to employ staff writers on a full-time basis. But I wonder what could be done to make the magazine(s) appeal to those home workshop users who don't see themselves as "modellers " - increasing circulation could only be a good thing long term ?

Forget the moderator tag at the side, I am entitled to and do have a personal opinion.

Does anyone else see the TOTAL hypocrisy in Nigel's remarks above ?

Openly states that he no longer subscribes to either of the magazines, admits to going into WH Smitt and company to read but not buy the magazine and then has the gall to come on here and say how things should be run and force his views onto the rest who have a right to be here ?

Perhaps before going all "Outraged of Nottingham" you might review the original post and read all of my comments before picking up on one part ?

A quick rough & ready calculation suggests I spent more with the various publishers of MEW and ME on subscriptions than I spent on buying, refurbishing & toooling my Super 7. Any normal business would be interested to find out why they had lost a regular customer - do Aldi (for instance) look upon my answers to their survey question as to why I don't regularly buy their fresh produce as hypocrisy, seeing as I say I don't regularly buy their fresh produce due having a had poor experiences with the quality in the past ? Or do they use the exercise to establish if there may be an issue to be addressed that may make me return if they addressed it ? And in the mean time, would they take issue with checking the quality of the produce prior to each purchase and deciding on a week by week basis if the purchase is warranted ?

Why don't we bring back the old reader's help voucher system when you had to quote a coupon number of of the mag to get a help query published.

And while you are at it, why not make these "closed" forums & put off a few more potential subscribers ? Or put your Moderator's hat back on and cull anything that doesn't toe the party line ?

[edit] Added TOTAL hypocrisy to the post

To continue to blindly purchase something that is not meeting your needs, just because you have done so for a long time, is stupidity in my book.

TOTAL stupidity ?

Nigel B.

27 replies before the inevitable "if you don't like the content, write your own" statement popped up !

I posted a similar sort of lament a number of years ago about MEW under the previous editor & got the same sort of reply so, after taking the first 210 or so issues of MEW on subscription, I quit. I had already dropped ME a couple of years before that for similar reasons to those initially stated.

I appreciate that there are new editors of both publications now, but the same business model is in place by the publisher and it appears to me that this is the basic problem. The editors are constrained by the publisher & until the publisher changes tune and employs staff writers (like most other mainstream periodicals) to generate content, rather than rely upon the "club magazine" format of the readership supplying the content, I am unlikely to return. I regularly pick up copies of both in the "WHS Reading Room", but have yet to feel sufficiently interested to buy a copy - that others are happy with the current situation suggests that I am in a minority (or am I ?).

I can see with my eyes that its really flat though

Define "really flat" ? With all due respect, your Mark 1 eyballs cannot compare to a 0.02mm/metre level whan it comes to sensitivity for detecting a bow or twist on your lathe bed.

Does it matter if a machine is absolutely "level" ? Apart from that being a requirement (the first test actually) of the much quoted "Schlesinger tests", probably not. More important is that the use of the level indicates with great sensitivity whether or not the bed is twisted or bowed. And your Clarke bed will almost certainly be a 5 sided box & not solid, so it will be capable of being twisted (it would be capable of being twisted even if it were solid - it would just take more force to twist it).

A couple more examples :

A fitter had been struggling to bed the crossrail onto a vertical borer column - if you are unfamiliar with vertical borers, I have put a photo in an album on here (I think !). Basically a lathe sat on the end of it's headstock with the bed pointing upwards, the cross rail is the "saddle" & the part is cut with the equivalent of the compound slide on a standard lathe (the crossrail is clamped while machining & is moved to suit the height of the component).

The column was about 2 metres square section by about 4 metres long (high in normal operation), opened ended & hollow but extensively ribbed internally and had been laid on it's back on a couple of sleepers. I would guess it weighed about 5 or 6 tonnes. The crossrail (a hollow, ribbed casting) would have weighed a couple of tonnes - far too heavy to push on the blued-up column ways, so a pulley system had been rigged to pull it using the overhead crane. The (experienced) fitter had been on with bedding & aligning this for about a fortnight & I was asked to find out what the problem was. Turned out he was "chasing his tail" - couldn't get consistent results & didn't know why. First question I asked was had he levelled the column - no came the reply, something that big won't move, so didn't think it necessary & hence just placed it on two sleepers. Not convinced, I found 4 levelators (precision wedge type levelling blocks) & we set to and levelled the column. Two days later the job was completed - bedding / aligning had gone the way the fitter had expected due to consistent, repeatable readings from the now stable column casting.

A Butler Elagmill milling machine was sent to us for a rebuild & retrofit (basically re-machine the slideways, replace ballscrews & bearings etc. and rewire the machine with a new CNC control & drives). In the works (& before return to the customer) the alignments were repeatably within spec, but on site they could not be consistently demonstrated. The rather gung-ho fitter was all for breaking out his scraper and diving in, but the MD wanted a second opinion. Turned out the customer had moved the machine from it's original location (on a purpose installed foundation block) and had rag-bolted it to the factory floor. Unfortunately, the position chosen had put the machine bed across two concrete floor slabs & the machine moved whenever the gantry crane moved across the joint. When this was pointed out, the machine was moved back to it's original foundation, where it was then stable & we could show the same alignment results that we had seen before shipment (and with no further scraper action !).

With regard to my physical capabilities, be assured that I am no Schwarzenegger ! At 5'9" and about 12 1/2 stone & with both wrists having had carpal tunnel decompresion operations, I cannot bring a huge amount of pressure to bear on a spanner - but I can twist a vertical borer to tweak the alignments without too much effort.

No problem at this end with trying to answer "piqued interest" questions if my experience may help.

Nigel B.

Most modern made machines now, even the very cheapest ones, are likely to be as flat and true as a proverbial pancake

There is a long running thread on here for an inexpensive Chinese made lathe with a German sounding name that suggests this is cannot be taken for granted !

Having spent nearly 40 years (where did it all go !) working with machine tools in industry, I can only suggest that similar methods to those used when (quality) machine tools are built are used to systematically track down errors. All the fitters I have worked with (trained the old fashioned way at the likes of Asquith, Butler, Stirk, Crawford Swift etc. ) have been quite emphatic about building & checking machines from "the bottom up" - each part, starting with the bed & working upwards, is "right" before moving on to the next. While there will no doubt be howls of protest about the need, that starts with a precision level to make sure that the bed is indeed without twist or bow. The headstock is aligned to the bed using a test bar in the spindle taper, any error to be upwards & towards the toolpost only. Likewise the tailstock is aligned to the bed using the testbar & again any error to be upwards & towards the toolpost. Without being systematic & eliminating errors as the build progresses, it becomes very easy to start chasing your tail to eliminate errors later on in the process.

"Rollies Dad's method" may well "get you by" if the machine is not too bad to start with, but I wouldn't want to track to down the root cause of a problem using it. Introducing an unknown amount of twist to the bed to try and get a machine to perform satisfactorily does'nt seem the way to go to me, but seems to work for some.

Latterly at my last employment most of the rebuilds of CNC machines were larger centre lathes & vertical borers. They look very substantial (upwards of 16 tonnes for a 48" -54" vertical borer) but can be twisted quite easily & getting the final alignments "to spec" relied upon the machines being bolted securely to a substantial floor and "tweaking" the levelling bolts to twist the machine to get the levels & squareness within tolerance. Machines vary considerably in their stiffness - as an example I had a customer in the West Midlands who had 3 centre lathes of similar capacity (about 500mm swing / 3.5 m between centres IIRC). One was of British manufacture at the lower cost end of the market (no names !), which required bolting to a substantial foundation block cast into the floor to get (and hold) alignment. The other British lathe (up the price scale) was just bolted to the factory concrete floor. Finally was a Russian machine, which had a massive cast coolant tray integrated into the bed - this sat on the floor unbolted, with the only levelling required being to ensure it didn't rock & the coolant ran back to the pump ! Of the three, the Russian lathe was the most used & most popular with the operators.

Take nothing for granted !

Nigel B.

The only time you'd vere need a test bar with MT on it is to check the centre in the spindle is concentric

And to check the headstock & tailstock alignment with the bed.

Leastways that is what we used when rebuilding CNC machine tools at my last employment.

Nigel B.

Been offered the link above at £400 but again unsure

I am on my 2nd one of those - and only on the 2nd because I was given a complete new base FOC (right place, right time !) and bought a new head & column assembly cheap (again, right place, right time !) so had effectively a new machine for very little outlay. My original used one was sold to a friend for what I paid for it.

Pros : good capacity for footprint, easy speed change, head keyed to column, head adjustable to horizontal, ejecting drawbar, 2MT tooling

Cons : geared head not exactly quiet, short quill travel (40mm or so), no quill fine feed.

The column & head lift out of the base & the two parts are just about managable single-handed. Looking at the link provided the speeds are different to mine, but that may be a speed plate for 60hz motors. They have a fibre gear early in the gearbox that can shed teeth, so check that it runs OK. Both mine have slight X-Y squareness errors - the first one was a bit worse at about 0.003" over the Y travel (5.5" IIRC), while the current one is about 0.002". I have yet to get the scraper out to sort this. The bracket that holds the column to the base is adjustable side-to-side with grub screws & fore-and-aft with shims to get the column square. If you get a bit too enthusiastic with the feedrate the head can push out of true, but I only did this the once early on (too used to industrial stuff !). I use 2MT collets to hold cutters with minimum overhang.

The lack of quill fine feed isn't much of an issue - the quill feed has an adjustable depth stop & I usually work by bringing the quill firmly against the stop and locking it, then using the head feedscrew to touch off the top of the job. Release the quill clamp. retract the quill and move the job from under the spindle, apply required downfeed with the head leadscrew and clamp the head, then bring the quill back to the depth stop & clamp. As the head is keyed to the column, there is no loss of position moving it.

I have no regrets having bought this (these) machine(s) & will be keeping the current one regardless. I would guess that the reason they disappeared (this model was offered by many sellers at one point) was cost of production. I think you would struggle to get another machine as capable for the same money.

£0.02

Nigel B.