Member postings for mgnbuk

We have been using the "Insize" brand calipers sold by Cutwel for 3 or 4 years now at work. We have several & not yet had one fail. The 3V CR2032 batteries last very well too.

Less costly than Mitutoyo & it's worth getting on Cutwel's mailing list for the monthly special offers.

Nigel B

Looks like no trace remains of the Tom Senior empire.

I can recall the old works, but IIRC the site was re-developed several years ago. I have a recollection that Seniors was bought out by Denfords & that the old works had Denford signage when it lay empty until it was demolished. Probably went around the same time that Mercers closed down & their site was re-developed for housing.

Nigel B (also not a million miles from Liversedge !)

I have between 3/4" and 1" max to get in between two cabinets

The Wera 8001A head is 12.2mm thick. The Allen key bits I have are 25.2 long & a bit inserted in the head measures 27.3 overall. The bits have scope to be ground down on the 1/4" hex part by around 7.5 mm, retaining the full length of insertion into the bolt head, so this could just about meet your criteria.

HTH

Nigel B

Or does having a higher HP motor mean they will have more torque at the low end of the speed range than a smaller HP motor would running at the same speed.

Yes - fitting an "oversize" motor to get decent bottom end performace without a gearbox is not unusual. IIRC my Denford Triac direct drive spindle motor is around 1.5Kw for that reason.

Nigel B

type in 1/4" drive you get every socket set supplied by man and beast.

Try typing "1/4" hex bit ratchet" into Ebay - brings up many makes & types from around £8. The Wera 8001A I Iinked to earlier is on Ebay for £22 - about what it cost (+Vat) from RS Components 3 or 4 years ago.

Nigel B

Pretty obvious that hardening should be done before regrinding. But I don't understand the comment that "so he is already undersize".

Beds to be hardened were machined to have a bigger finish grinding allowance prior to hardening than soft beds, as hardening caused distortion that was subsequently ground out. Your soft bed was ground to finished size so, as it stands, it does not have the distortion allowance any more & so is "undersize" for hardening.

That was "Original Myford's" explanation to me.

Hopper - any machine shop in possesion of a surface grinder & cannot produce a reasonably flat surface with a reasonable finish should not be trading as such !

Nigel B

As regards hardening I think he can forget that. Hardening is done before grinding so they can take any warp and twist out of it, so he's already undersize.

That was what "Original Myford" told me when I inquired.

Any decent machine shop with a suitable surface grinder should be able to regrind a flat bed lathe - suitable meaning long enough travel to accomodate the length of the bed.

Nigel B

I use a Wera 8001 1/4" ratchet bit driver, like this :

**LINK**

RS Components used to sell them (where I got mine from), but I can't find it now with their hopeless search engine.

It is very small, but beautifully made & gets into very confined spaces - it has got me out of trouble on many occasions. Not cheap, but very worthwhile.

Nigel B

I never had much success with Mercer tenth thou clocks at work. I had a couple that were bought new & used soley for final inspection checks. They were calibrated & cossetted - always stored in their original packaging in a cupboard away from the shop floor. But after a couple of uses they would start sticking and giving unreliable readings, so were sent away for looking at - almost always they were not economically viable to fix. Nobody could suggest why they appeared to be working fine when carefully packed away, but would not work reliably a few weeks later when next required. The Mercer thou clocks didn't seem to have this "issue", only the tenth thou versions. After two or three similar episodes, I changed to a Mitutoyo micron clock & never bought another !

No experience of John Bull clocks, so can't offer an opinion.

Nigel B

Central heating pumps are pretty rugged and silent

But CH pump motors have sleeve bearings that are lubricated by the pumped liquid, so would require pretty good inlet filtration to give reasonable bearing life.

Nigel B

Hi Murray,

Not one of mine then !

I have fitted many MT30s over the years - we used to buy Bridgeport Interact spec. combined motor / ERO115 encoder units by the pallet load at one point ! Very reliable if not abused - just as well these days given they are obsolete & parts supply limited. Tachos going open circuit on one winding was the main failure IIRC & the tach armature cost about half as much as a new motor back then.

I have not seen a Micon control for many years - Broadbent Hayes used them occasionally on a (truly awful) VMC they called the Digimill, though most had Anilam Crusaders or a PDP8 based Israeli system. One of the first solo service visits I did was to one of those at a toolmakers near Heathrow airport sometime in 1982. IIRC Micon were an offshoot or successor company to Posidata. The Broadbent Hayes Digimill rights & all parts went to a company in Poole called Micon White when Brooke Tool pulled the plug on their machine tool interests early 1983 - I don't know if the "Micon" was the same outfit, though.

The Chinese Fanuc clones look pretty good for the money, though be aware that the popular 990 type appear to be open loop, with step / direction outputs & no axis feedback provision.

It will be a capable machine when you get it running - good luck !

Nigel B

That is pretty much as I do it, but rather than running direct on the table top I set up on a slip block or parallel. When the DTI is zeroed one side, slide out the slip block, rotate 180 degrees & gently slide the block under the clock to take the reading. I generally don't have the DTI bearing on the slip by more than 1/4 of a rotation of the needle, so that the likelyhood of disturbing the setup when the slip block is slid in & out is minimised.

I used to use a "bobbin" at work for this - basically a roller out of a large roller bearing sat "end-on". This had the advantage of having a nice radius on the end, so the DTI plunger didn't have to ride up a sharp step. Must have put is somewhere "safe" as I can't recall seeing it for a while !

What was the reading like front to back ?

Nigel B

Steve - no apology required on my part. If you have a query, then post it !

How would I check column perpendicularity? I guess I'll need a huuuuuuge engineer's square and my most trusted DTI??

Basically - yes ! Doesn't need to be a huge square, but you do need to be able to trust it - likewise your DTI. Most of the inexpensive blade squares are "Workshop grade" at best & would be worth checking out before you start. A precision square is not cheap & it might be worth investigating making a cylinder square if you have a lathe that can be adjusted to turn parallel between centres. Or you could get a good idea with a precision box (or frame) level - level the machine base accurately, then check with the side of the box level how the column lies - but these are expensive toys as well.

Remove the head at the swivel point and check for burrs or dirt on the mating surfaces .

Lift the column up off the base and do the same as above .

Plus give them a rub with a "known to be flat", blued-up, surface plate to make sure that there are no high spots or burrs on all mating faces. Check the column-to-base squareness in both directions after re-assembly before bothering with tramming - you want to know that is correct before proceeding IMO.

Nigel B

Murray,

What control system has your Matchmaker got fitted & do you know anything of it's history ?

At my last employment we retrofitted quite a few of those - most seem to have originally been fitted with Posidata stepper motor controls & we changed those to Heidenhain controls with Indramat drives & SEM DC servomotors like the ones that appear to be fitted to your machine. Be interesting to see if its one of "mine" !

Nigel B

No typo.

After an apprenticeship as an electrical/electronic technician specifically set on to learn all aspects of the maintenance & repair of CNC machine tools in a process control valve manufacturing plant (which I finished at Boxfords when that company closed), I spent around 18 months at Broadbent Machine Tools production wiring manual & CNC machine tools (semi-automatic Oil country lathes & CNC vertical milling machines), plant maintenance & customer service. After being made redundant there, for 27 years I worked for a machine tool rebuild / retrofit company in Halifax, variously changing CNC control systems on NC/CNC machine, rebuilding NC/CNC machines back to original mechanical specifications & replacing and upgrading the electrics/electronics, and converting manual machines to CNC (sometimes with & sometimes without a mechanical rebuild). Started as a Technician, promoted to Senior Technician & promoted again to CNC Retrofit Manager. Machines worked on varied in size from Bridegport size turret mils up to floor borers, Colchester Student size lathes up to roll turning lathes & vertical borers up 14' table diameter. Customers were in many different fields, but the later machines went mainly to aerospace subcontractors. I current work on "maintenance" of all aspects of plant for a specialist graphite machine shop - "maintenance" including sorting out CNC machine bought at auction, including control retrofits (though last week was changing the coolant pump on a 200Kva diesel generator - never a dull moment !).

"Thou per foot" does not strike me as being too arduous a spec. to aim for, even for "entry level" stuff - the Spanish (Lagun) built, Ajax branded turret mills we used to fit a complete drives & control package to were within that, as I recall. Anything with "borer" in the title was more of a problem - usually much tighter limits to work to & everything tied up - levels first, then alignments & all had to be demonstrated to the customer for acceptance, using calibrated inspection squares, levels etc. & later a Renishaw laser interferometer and dynamic ball bar system.

I only failed to have one machine accepted in the time I was there - a manual jig borer converted to CNC, on which the customer had more than halved the original builders straightness tolerances in his conversion specifications. The original spec was 0.025/300, customer had specified 0.01/300 but the best we could get was 0.014/300 on the side of the Z axis - machine not accepted for the sake of 0.004 mm !

Nigel B

Look at how many 20 year old cars still have the original sealed alternator bearings running just fine.

And how many vehicle alternators use taper roller bearings ?

You are comparing apples & pears here - vehicle wheel bearings these days are sealed for life angluar contact ball bearings, alternators are ball bearings, many plummer blocks are ball bearings - as I said earlier, over greasing ball bearings is not a good idea. But taper roller bearings work a little differently - well, that is what the Timken Design manual said when I had to consult it for the design of a machine tool spindle bearing arrangement some years ago. I don't have access to that manual any more, but do recall the comments about taper roller bearings having a "pumping" action on the lubricant & I believe that is the reason for recommending a periodic regreasing on taper roller bearings that may not be required on ball bearings.

Nigel B

Before you trammed the head, did you check the column squareness to the base in both directions (X-Z, Y-Z)?

Pretty pointless tramming the head if the column isn't square to start with IMO.

My former machine tool fitter collegues used to work to a "rule of thumb" for manual machine alignments of "a thou per foot" (0.001" per 12" or about 0.025mm per 300mm) - on CNC machines we generally aimed for half that. Your Y-Z reading of around 0.004" in 6" is around 8 times the "rule of thumb" - only you can say if this is acceptable for the class of work you aspire to, but I would not be happy with it. Time to get the scraper out !

Nigel B

Waste heat is so often wasted

Indeed so. I did float this as an idea some years ago, but there was no interest on the owner's part. Less initial investment (under £400 IIRC) for the large heater & red diesel bought 8000 litres at a time is (currently) quite cheap (around 50p / litre or less, I think). And it is possible we will move premises at some point, so less incentive to plumb up the place. I would like to use some of the unused electrical capacity of the generator to run a couple of 25 Kw electric space heaters, but that would also involve a fairly large capex as there is currently no spare capacity on the distribution boards.

I am aware of the potential effieciencies of using all the output from a genset - my brother is involved in such installations for commercial premises, using large V8 diesel engines converted to run on mains gas (different pistons to lower the CR & an ignition system fitted). IIRC he quoted something like 96% of input energy harvested from the generator, coolant & a heat exchanger in the exhaust system. I doubt that I could get that from our 20 year old 7.5 litre Iveco turbo diesels, though !

Nigel B

Taper roller bearings behave differently to ball bearings where grease is concerned - ball bearings "churn" excess grease & this generates heat, whereas taper roller bearings have a "pumping" action that moves grease though the bearing & expels the excess. IIRC the grease is moved from the large end of the rollers to the small end.

SKF don't recommend using moly or other additives in grease for bearings, just normal lithium soap grease.

Nigel B

We use a couple of SIP Fireball diesel space heaters to warm a (bigger than yours) workshop at work. The larger of the two is rated at 52Kw & it really belts out the heat, but uses around 5 litres of red diesel per hour - the smaler one is about 15Kw & uses about 2 litres an hour. We have a diesel tank on site though (as we make our own electricity via a 200kva generator) so have no shortahe of the red stuff - I modded a 205 litre oil drum to have hose & valve that lives inside the works to fill the heaters & use a barrel full a week at the moment.

The only time it smells is if it is allowed to run out (when there is a cloud of vapourised, non-combusted diesel fumes) and after switching off (when it just whiffs a bit "dieselly". It doesn't seem to make as much condensation as the propane heaters we used before converting to diesel, a change made mainly due to rises in the cost of gas a couple of years ago - we were using a large (52Kg ?) propane cylinder a day & they went up to £70+ each.

I have not had any comments about my collegues feeling unwell due to fumes in the main workshop, though the workshop doors get opened during the day to get in & out with a FLT. The smaller heater was bought for a smaller workshop & the chap working there stopped using it after a while as he was getting headaches & attributed these to the heater fumes.

They can be finicky to keep running & are not maintenance free - there is a small compressor mounted on the rear of the fan motor that blows air through what looks very like a spray gun nozzle in the combustion chamber - this what draws the fuel from the tank & generates the fuel/air mix that is ignited by a continuous spark between two electrodes. There are a couple of filters to clean on the compressor inlet & the spark electrodes can short out through dust contamination (though that may be more due to our graphite machining environment & may not apply to you !).

HTH

Nigel B