Here is a list of all the postings Nigel McBurney 1 has made in our forums. Click on a thread name to jump to the thread.
|Thread: fly cutter wear|
with a low speed of only 250 rpm and a cutting speed of 100 feet per min ,the max radius of cut using HSS tools is only about 3/4 of an inch, tool wear is due to using too high a cutting speed, If speed cannot be reduced then carbide is the answer, the older style carbide cutters with the carbide brazed to a steel shank produces quite good results,better than using screwed on inserts ,the brazed shank is more rigid.
|Thread: interest renewed|
long ago I kicked off model making at home with a Fobco Drill,Myford 7 and a home made bench grinder. I used a vertical slide for milling , It did all I required when building an Allchin T E I held any milling cutters in a brand new Burnerd chuck without problem and did most of my milling using various home made flycutters only using end mills /slot drills when a slot or pocket was required to be machined,as fly cutters cost virtually nothing and I was well satisfied with results I achieved with the Myford slide,at the time I worketd in a brand new toolroom with a Deckel FP3 one of the worlds best milling machines of its type,,i did not go home wishing i had better equipment ,I was content with what I had. 3 jaw chucks are ok to hold cutters provided the jaws are in good condition and not bell mouthed, if a cutter slips in good chuck then perhaps one is overloading the whole set up plus the advantage of a chuck to hold the cutter is that the mass of the chuck dampens vibrations, Full size Fritz Werner milling machines had a built in flywheel on the machine spindle, to reduce vibrations,55 years later a wide range of tool holding and small milling machines are readily available. The ER collets are good for cutter and drill holding ,though I still prefer the Clarkson screwed shank cutter system when say working on a vintage engine crankshaft ,re cutting a keyway where a cutter coming loose or just moving in the collet could cause irreparable damage.
|Thread: Facing parallel between centres.|
Best thing to come out of this discussion was the suggestion to use a jubilee clip as a driver where a conventional driver cannot be used. To turn a part to obtain good parallism use a substantial cast iron sub plate bolted to the faceplate and then lightly skimmed flat, I use a scrap rotary table casting then bolt the work to this subplate , for brake discs they are bolted to the subplate and then skimmed on both sides at one setting, face plates are a useful tool though they will distort if clamps are over tightened, or the work mounted to the plate is not flat, Face plates in practice cannot be made too thick or rigid as they would reduce the lathe gap clearance when used on general work.
|Thread: Faceplate workholding.|
I think an improvement on Jasons soft headstock centre is that I have found that with cutting pressure and tailstock pressure ,the temporary centre can slowly retreat towards the head stock,despite having a newish chucks in good condition. so I reduce the diameter of the bar on the the end that goes into the chuck so that there is shoulder to stop the centre sliding in the chuck jaws. then as a further improvement I get a circular steel blank around 4 to 5 inches diameter ,drill a central hole to suit the larger diameter of the centre and weld it to the centre,positioned about 1/2 inch away from the chuck jaws so that the weld is clear of the shoulder, then drill a hole towards the o/d of the blank,to take a bolt and two nuts which then makes a driving dog for the lathe carrier to drive the work piece.By only skimming a small amount from the centre point each time it is set up ,it takes ages before the cebtre becomes too short,Advantages -a dead true centre every time,and its a lot quicker than removing an 8 inch chuck ,fitting the usual hard centre and then refitting the chuck,I use this arrangement on a Colchester, on a smaller lathe the drive disc could be a press fit or loc tighted if no welding facilties are available,
|Thread: Harrison M300 - am I going crazy?|
I have owned a number of Colchester lathes,and I believe Harrison lathes are part of the owning group, my current Colchester ,a 1970s Master 600 is an imperial lathe fitted with dual dials (imperial/metric), now I did a naughty,when I bought the master I still had a metric Colchester student now this was fitted with a saddle handwheel which had a metric dial which indicated the travel of the saddlein metric units so I tried it on the saddle of the Master and it indicated accurate metric travel even though it was basically an imperial machine with imperial lead screw, so I kept it on the master and eventually passed on the student minus its dial.So for an imperial machine the rack and gearing in the saddle must be metric.Very useful ,now having served my apprenticeship 60 yrs ago by habit I work mainly in imperial as thats the way I was trained so now I use the top and cross slide in either metric or imperial and use the metric only saddle dial ,its ok I have just get used to it,I dont know if Colchester offered a dual dial for the saddle dial ,if they did it no doubt cost a fortune,Colchester spares costs are eye watering. Also at the time I also had a colchester Triumph ,this was a full all metric machine including a metric leadscrew,the saddle had wheel had a machined feature to recieve a dial ,and after some checking I found that the rack was metric and a dial could be fitted to the saddle handwheel which would indicate 25 mm for one turn exactly. So I found a merical dial at a local tool dealer,it was not Colchester but it was soon made to fit. Now Colchester and Harrison having a common link it may be worth checking if the Harrison also has a metric rack,it would then be easy to fit a dial .Getting back to the original query,in the olden days the majority of lathes did not have any means of indicating saddle travel,even a new expensive 1967 toolroom lathe I worked on had no way of measuring saddle travel, but of course no one worried you were trained to turn using topslide ,or bed /saddle stops stops or a good 2 foot rule,So dont moan about it just get on with it at least you have a decent built English lathe, the victorians had it a bit harder a lot or evem most of their lathes had no dials, when I was young ,my very old neighbour still owned his fathers machine shop,the lathes,belt driven ,2 six inch and one 12 inch centre height had no dials at all,it was a case of marking the handles with chalk and universal use of rule and firm joint calipers ( never spring joint) , and just look at what the Victorians produced.though the universal trade term "fitter and turnet" was literally just that,you turned the work and then fitted it ,the scraper was a popular tool.
|Thread: Is a hand scraper pulled or pushed?|
Back in the 1950s/60s I worked for a firm who made scientific instruments,one product was spectrometers which need an accurate "slit" of light ,the slits made from nickel silver,had a fixed and sliding jaw to adjust the width of light slit. To get the edges of the jaws absolutely straight the jaws were lapped on a cast iron plate which had been "loaded' with very fine abrasve, to prepare a lapping plate ,tthere were 3 circular plates about 9 inches diameter and fitted with circular hardwood handles, which screwed into blind holes in each plate with a very coarse thread, A steel threaded circular plate was fixed to the bench with wood screws,so you have one lap plate fixed to the bench and one plate with handle screwed on held in your hands ,some abrasive was sprinkled on the lower plate,the top placed placed on the lower plate and the top plate was lapped against the bottom plate with a circular ,cum figure of eight motion,hard work ,until the plates had an even grey colour,then the top plate was removed and the third plate lapped against the bottom one, following a pattern all the plates were lapped against each other in turn and thats when I learned about Whitworths motion. the pairs of light slits were mounted in pairs in a small fixture and then lapped to get straight edges, great care had to be take to avoid "rolling" the fixture resulting in slightly cureved slits.Long time ago now but I think the lapping lubricant was water. On every bench there was a circular surface plate ,Long before I started these plates had been made from iron castings and faced up in the lathe,they were then flattened by the Whitworth lapping motion,as they were surface plates rather than lap plates the abrasive grains in the surface were killed by carefully rubbing the plates with a very fine oilstone.A five year apprenticeship plus a further year was enough of that though it was very good training I went down the road making prototype parts for early automatic typwriters for another pound an hour,lot of money then.
|Thread: Ideas to remove metal before using cutter|
I found that EN8 can be toughened using big calor blowtorch and then queching,snag is that it also shrinks,
|Thread: Mild Steel Problems|
Steel with hard inclusions is not worth bothering about,throw it in your dustbin,you have hit a hard spot under the drill it might be worse in other areas.
|Thread: Quality Finish|
Use HSS tool with about 15 degrees top rake,small radius on tip and hone with an oilstone,soluble oil is ok though a drop of liquid ROCOL helps, reduce speed to 40 to 50 feet per minute.
|Thread: How good is a good faceplate?|
I would expect most ordinary lathes after some years years use to have some run out,expect a thou. Faceplates are easily distorted when jobs which are not flat and stiffer than the faceplate are bolted down too tight,a faceplate which has a permanent distortion has to be skimmed. To get a job machined very parallel,get a subplate of steel or alloy,mount this on the face plate skim it true then mount the work on the subplate using clamps and tapped holes in the sublate,alternatively a round sublate can easily mounted in a 4 jaw chuck . only snag with subplates on larger jobs is that the length of gap is reduced.For some skimming jobs such as brake discs I have the the slotted table removed from an old rotary table,this gets mounted in the 3 jaw and gets a couple of thou skimmed off when ever I use it,eventuall it will get too thin but not in my lifetime. A large old brake disc could be used as a subplate,mounted in the 3 or 4 jaw chuck.
|Thread: What lathe tool for deburring holes?|
I use a long half inch square toolbit mounted in a Dickson toolholder ,the tool protrudes out each end of the tool holder ,one end is ground with a 45 degree angle plus some top rake so that it will chamfer say the end of a bar from a tiny chamfer up to a large chamfer, the other end of the tool bit is ground with a 45 degree chamfer plus top rake and with lots of front clearance similar to a boring bar so that it will again produce a fine chamfer or a large one. the tool is a permant fixture in the tool holder , to cut internal or internal chamfers all that is required is to rotate the main tool holding block through 90 dergrees,or just change the position of the tool holder. this works well and will deal with most materials including brass on my Colchester.For the Myford I have have a similar set up with a long 5/16 square tool bit though I find that the top rake does not cope with brass so well so I also have a zero rake similar tool. when instrument making usual shop practice was to use a M&W 3 cornered triangular scraper for bores, mainly in brass turning, and a very fine 6 inch file for taking the edge off external corners ,sometimes a graver would be used if a sharper profile chamfer was required , personally I found the M &W scraper a bit too large ,so made a finer scraper from a 4 inch triangular file with a turned up wooden handle,60 years later I still have it. The long toolbit chamfer tool was not my idea,I found one in a box of tools donated to me,the property of a deceased toolmaker,its in constant use and have the Dickson holder visiblaly marked so that I can grab it quickly.
|Thread: Can a small lathe handle a tail stock die holder?|
Surely the problem in the original post is ,""the tailstock was allowed to travel along the lathe bed" this practice is wrong the tailstock must be locked firm, and the die holder allowed to travel on its mounting rod held in the taper or the tailstock chuck. the torque on the dieholder must be resisted by a tommy bar NOT the key/keyway in the tailstock barrel,When using the dieholder under power the torque can be resisted by a length of bar held in the tool post,the bar is parallel to the lathe axis . the type of thread is not mentioned,unified fine ,40 tpi ME ,or brass thread might just be possible but it is not good practice to abuse your lathe,the safety device could be that the steel rod usually slips in the 3 jaw chuck.
|Thread: World's Biggest Tractor in 1915 -- Aussie ingenuity at its best|
I understand that it had an English built Blackstone oil engine,and it completed its journey.
|Thread: Drilling brass|
A commercial screw brass material will probably be tougher than the usual brass rod, so I would not back off the drill cutting edges with a stone, and then use coolant ,its a long hole and drill runing at high speed,the drill needs some lubrication on the flutes. My experience when at work was to turn brass dry on the fast plain bed lathes,and full flood soluble oil on the capstan lathes,the coolant kept the tools cool and flushed away the chips.
|Thread: Is a drip feed coolant advisable|
one favourite method of applying soluble oil to small jobs in machine shops and toolrooms in the 1970s was the cylindrical plastic bottle which originally held Fairy Liquid washing up soap, there was always one on the end of Bridgeport tables for giving small jobs a squirt,then fairy changed the bottle shape and material. when I started it was any old tin or glass container with slurry brush dipped in it,either an old 1 inch paint brush or commercially made brush where the handle was a pair of twisted wires and the end wires wound around a bunch of bristles.
|Thread: EN3B Mild Steel is a pain or is it me?|
Regarding EN 3b for most purposes it is best to AVOID using it, though it is used on some full size boiler work ie stays and studs,it does not machine well,it tends to tear. I have a S7 and a Colchester master and it does not matter what tooling is used,you have to be really careful to achieve a reasonable finish. Regarding parting off it was usual practice to use halve the normal speed,though higher speeds could be used on brass.Very good results can be obtained with EN 1A freecutting leaded steel,though it is best not use it in welded construction,though higher speeds can be used ie over the normal 100 ft per min for the softer steels,En1A is a better general use steel,with free cutting properties ,I do not stock any en3b , En 8 ,a tougher steel I use for vintage engine studs studs and always have a stock in my metal rack, En 16 is good for replacing the bent shafts and pins for farmers equipment,though I never weld it, my welder mate always said dont weld anything tougher than en8 ,unless you are a skilled welder.
|Thread: Inserted cross slide feed nuts|
unlike v threads ,square threads have clearance on the o/dia when cutting a square thread during my apprenticeship I was told that these threads have 10 thou clearance on the odia,this applied to all such threads irrespective of diameter. I have made a number of square threads over the years from the brake screw on a 1 1/2 inch Allchin TE to some full size brake shafts on Avelings and Fowlers and a very long screw for a sluice gate,all these had a good clearance,Its the fit of the flank of the threads that matters,looking at the photos of the cut brass nut,top and bottom clearance looks minimal or nil. One of my next jobs is 4 square threads for the jacking screws of a 1920s showmans living van,bit difficult at 4 tpi, one unusual feature of the thread is that the depth of thread is half the normal depth.
|Thread: Welding precautions|
Many years ago ,a friend owned a garage,I got one of his men to do some "cash" welding on the front underside of my wifes morris traveller,I sat in the cars passenger seat with a bucket of water,then went up with the car ramp,with the welder under the car ,when things got a bit hot and smoky i sprinkled water on the hot bodywork, I always remember one thing I saw on that saturday afternoon,high up on the ramp i could see there was a mark 3 Cortina right over the back of the garage, a real cut and shut ,front an back were two different colours some doors and other panels were in further different colours.I had made up the sheet metal panel I wanted welded in place from good clean sheet metal formed up in a metal bender ,the welders comment " we dont see good material nicely bent like that,we usually cut up an oil drum and beat it flat to get some steel.
|Thread: Selling on behalf of executors in 1975|
Did those prices in those days after the war include purchase tax? that dreaded variable rate tax. My Ml7 in 1968 was listed as £82 basic spec ie no motor and only supplied with faceplate,catchplate,and centres and 3 spanners and oil gun,not sure about a backplate,by the time I bought the motor ,3 & 4 jaw chucks ,tailstock chuck, plus some other bits the cost was £120 exactly the same as a basic super seven. Skilled wages were around £20 per week gross in the south of england. I also rode in motor cycle trials at the time and a Greeves alloy cylinder barrel and head to improve the performance of the iron barrelled Villiers 250 engine cost cost over £50 so I thought the Myford lathes were very good value at the time.
|Thread: Thread identification|
A long time ago one of the many students in company where I worked was advised to come and see me as he had a problem identifying a thread on a Honda motor cycle and I was into bikes. the thread was around 12 mm and the pitch was really odd ,not in any engineering thread tables,so I contacted a tap and die supplier, to be informed that it was quite common to find odd threads on Hondas and other far eastern products.Around the same time a friend had a gearbox bearing fail in a Dihatsu 4 wd ,similar reply from local bearing supplier ,thats off a Dihatsu only available from a dealer and will cost an arm and a leg. I wonder are the manufacturers being devious,and they can supply spares at high prices, or has a designer come up with the correct specification for the part in hand and the parts are made in such high volume that variation from standard does not increase manufacturing cost.
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