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: Making a 5C Collet Chuck|
Assuming your Boxford is the usual 4.5 centre height with a spindle bore of just over 3/4 inch , I would say that a fixture holding a 5c collet would protrude a bit too far out from the front of the lathe spindle for my liking ,work will tend too chatter . The Boxford where I worked had a set of Boxford collets ,there was a nose piece which fitted in the spindle taper, collets up to about 1/2 inch capacity,and a collet draw tube which slid into the spindle bore,one end screwed onto the collet the other end had an aluminium handwheel for tightening the collets by hand , The advantage of this system is the work is much closer to the spindle nose, and long lengths of rod would go the length of the spindle. I expect Boxford collets could be found it was 50 years ago that I last used that Boxford.
Some time ago I bought a Marlco indexing fixture at auction,it was fitted with a 5c geared scroll collet chuck and had one collet , I took it off and replaced it with a 3 jaw chuck much more useful , On removing the collet from the chuck I found it was left hand threaded, as I wanted to use my stock of 5c s from my Browne and Sharpe lathe I made a new r/hand nut for the chuck and then fitted the chuck onto a colchester back plate ,only snag to tighten the chuck the key goes anti clock ,so watch out when buying used collets some may be l/hand.
|Thread: What did you do today? (2014)|
I bought my Fobco 1/2 inch cap drill new £52 in 1968 and it is still going strong,it was expensive considering a Myford 7 was £72 basic ,with chucks ,motor ,l/screwhand wheel etc they came to £120 , About 20 years ago I bought a little used 3mt Meddings ,second hand for £325 which has been a superb drill ,one inch capacity and 100 rpm bottom speed (ideal For reaming). Cant beat english built products.
Spent the morning strimming around the place Strimmer on wheels 6 hp engine 4mm cord bit lethal but it does work well ,trouble is it getting a bit hard nowadays to find the energy to push it.
|Thread: internal screw cutting|
I was taught during apprenticeship,before screwcutting,clean the leadscrew with stiff brush held against the screw while it is rotating,flood it with oil then engage the half nuts and run the saddle up two or three times,this will get most of any debris out of the halfnuts ,then give the leadscrew another brush, if the lathe tool follows the initial tool mark once and then goes haywire on what is the third cut then either the half nuts were engaged in wrong position due to misreading the threading indicator(easily done) or engaging the half nuts on the top of the thread of the leadscrew,it has been known to happen ,the soft material of the half nuts will sometimes just catch thread top and move the saddle and cut the work if a very light cut is being taken,an operator should be aware that the half nut lever is not fully down but accidents do happen. Some endplay on the leadscrew will be taken up as soon as the saddle moves so will not cause the problem. I suggest beginners engage the half nuts when no 1 shows on the thread indicator,takes longer but stops errors. I assume the top slide is adjusted fairly tight or locked.
As an instrument maker ,a lot of threads were produced using chasers on plain instrument lathes with a threading attachment, and if anyone was threading say on a Boxford ,to save grinding a screwcutting tool a chaser would be used instead, of course one had to be very quick with both hands , the chaser has to be retracted from the cut just before the half nuts were disengaged , I once saw another apprentice get it wrong and disengage the half nut first resulting in a series of parallel V shaped rings around the work, !! I still use chasers for screw cutting (I bought a lot for £2 each some years ago ) at least they produce a full form thread and with care 8 tpi and smaller can be cut quickly in mild steel , bit tricky on bores ,getting the right depth and one hand on the half nut lever and the other on the crosslide but you do get nice threads with the correct form.
|Thread: Victorian Whitworth nuts.|
I have been restoring i/c stationary engines for 40 odd years, plus pumps and grain processing mills, all the stationary engines some now over 115 years old have machined hex nuts usually large size whit, , Ruston Hornsby used bsf on big end bolts by 1923 nuts were castle with split pins. Bamford made many types of cast iron framed roller mills for proccesing animal feed, frame bolts were coach head with square nuts fitted flat of nut against the casting,iteresting fact was the hole for the bolt head was cast square so that the bolt could not rotate when tightening the nut,time saving by only needing one spanner,the engineering bits of the mills had normal whit big nuts . Wooden trolleys and bearers for the engines had square nuts,flat against the timbers ,some had round washers or occasionally square ones. Lock nuts were all large nut then small nut,plus on big ends a split pin. American imported engines were similar though Amanco engines had two normal sized nuts for lock nuts, typical American logical production engineering,why have two part numbers ,its cheaper to make twice as many nuts of one size rather than produce two sizes and the assembler cannot get them the wrong way round,and by the way the US also used a larger size nut. Why the larger nut,well in those days spanners were generally carbon steel without any chrome vanadium alloy ,so the spanners needed to be larger,due to the lower strength of the steel . the war and the availabilty of better spanners and the large whit nut could not be used in restricted places in modern designs.
I think the era of machine and engine building in the first half of the 1800s was where square nuts were used as an engineering function rather than a more agricultural function,as square nuts were easy to make ,there was no drawn bright hex bar in those days and gradually replaced the wedge and cotter, the raised side of the nut fitted onto a cast surface may have been used as a self aligning feature ,proving it would be difficult as most surviving pieces of machinery have probably been stripped or rebuilt many times.
The arguments about lock nuts will go on for ever , but the facts are a lot of good engineering books from the 1880s onwards show thick nut on first, the threads were usually coarse pitch Whit and the bolts of relatively low tensile strength steel and it worked ,on thousands of machines ,if any further safety was required they put a split pin through the bolt just in case, Modern theory on locknuts relies on very high strength steels not available to the Victorians
|Thread: Gripping Drills in Chucks|
With drills now coming from all sorts of countries I have found that the new drill shanks tend to be a lot harder than the older English made drills,and this affects the grip of the chuckjaws on the drill,I also have a selection of solid carbide drills and these will slip a lot easier than an old Dormer drill,and are best used in the mill in a collet chuck,
Why do you need to drill with a 6mm bit at 200 rpm on I assume mild steel this should be a minimum off 500 rpm in black steel and in excess of a thousand for free cutting mild , and yes being well past retirement a longer chuck key makes up for lost strength.
|Thread: Lathe advice... I guess I will need one soon|
I would buy a 4.5 in or 5 inch centre height Boxford ,nice machine and English, I have restored a couple of 1950s/60s bikes and you do not really need a large lathe ,most restoration is new spindles ,brake hub skims,should be able to do a 6 or 7 inch brake in the Boxford(after the spokes are removed!!) make hex nuts ,bore a sprocket,long bolts for stands and footrests,bronze bushes etc etc, and get your money back if you get a bigger lathe.Though I found motorcycle restoration can get very expensive compared to restoring stationary engines or model making .
|Thread: COLCHESTER STUDENT HEADSTOCK ADJUSTMENT|
Pete, You have jumped to some conclusions despite not knowing what a Colchester looks like, Nowadays the Colchester is very popular for home use,as there were thousands of them made and spares are still obtainable. Many years ago they were not well regarded among skilled turners ,but they were popular for training schools and technical colleges and were available at a reasonable price ,by the 1970s they had improved ,beds and slideways were heavier and larger for example but they retained some features which were not ideal, one being the adjustable headstock, The majority of lathes had their headstocks fitted to the v or flat beds and finally aligned by fitting and scraping so despite a knock or two they could not move out of alignment any subsequent alignment problems were due to a lot of bed wear or misalignment on long bed lathes and would required very skilled fitting or a bed grind to correct matters. Colchesters went the other way.obviously to reduce costs why spend days scraping and testing a headstock when it can be made adjustable and very easy to align in the factory before all the bits ad pieces are assembled,and if one did get a bang it could be corrected.If you wanted a precision lathe then you went and bought a Dean Smith and Grace or a Holbrook and paid an awful lot of money for them. And a lot of Colchesters did get bangs at the training establishments ,the front edges of many topslides show rough encounters with chuck jaws. The big advantage of many of these ex training lathes is that despite a few knocks and dings on the machine surfaces and the odd broken handle they did not get much wear ,and were a bargain during the last 20 years though supplies appear to be now drying up. Also the advent of the hiab lorry crane has not helped matters, the correct lifting eyes in the bed get lost and the lifting slings are very often not correctly placed, for example around the spindle behind the chuck ,or a round sling through the spindle,the driver/ operators are just not careful enough.,they get certificates for safety not the skilled slinging of precision machine tools.So Your Colchester may need adjusting,and providing you take care it can be adjusted back to spec.
What really surprised me was about 25 years ago a large cnc vertical mill with only about 6 months round the clock operation needed the vertical slidebars replaced, the recirculatory ball bearing slide units had worn slight grooves in the hardened bars, thy were replaced (£10k) The machine was bedded onto 4 feet of concrete and the mounting bolts ran in sleeve nuts so that the machine could be jacked up or pulled down the vertical travel was tested and found to be out relative to the machine table so the fitter from the manufacturer using the sleeve nuts adjusted the column until it was vertical, the bed frame was a heavy steel fabrication so it was literally distorted ,to gauge the size of the machine the vertical head was just over a ton, There was no really skilled machine fitting about this repair, and we found out why the slides wore so quickly ,we were producing very precise aluminium castings but with very little machining allowance so the swarf was like dust,which had penetrated the slide covers and acted like a lapping paste,the manufactures had a similar problem with another customer who fine machining brass. I never thought I would see the day when an expensive machine was aligned by distorting the main bed.
|Thread: Round Aluminium|
Aluminium Warehouse is best and cheapest supplier for aluminium blanks I can find. After bitter experience with cast ali rims on an Allchin I would go for steel rims. my cast ali rims cracked when riveting the spokes.
|Thread: treadle power|
Oh I forgot why bother with a treadle,why not use a old stationary engine like a Lister D steady 500 rpm with a large solid flywheel ideal for driving a lathe.
50 years ago my neighbour owned a workshop set up by his father in victorian times and was never modernised, One of the lathes was around 6 inch centre height and was set up for treadle drive and line shaft drive, early lathes could be quite large in capacity but their spindles were small,very often solid and easily rotated.I asked how did their workers manage to treadle a six inch lathe,he replied that tredalling was used for small quick jobs where it was not worth getting the line shaft working though he said the treadle worked well and was easy to operate, perhaps if an operator complained they got the sack. none of the lathes had index collars on the cross slide screw,the screw had a square end to take a simple handle,operators worked to chalk marks,a steel rule and stiff joint calipers,that was skill, how different to modern times when folks cannot seem to be operate a machine unless it has digital readout .
|Thread: Myford Super 7 - Adding Power Cross Feed|
Why does anyone need a power cross feed on a Myford?
|Thread: COLCHESTER STUDENT HEADSTOCK ADJUSTMENT|
Hi I have adjusted my master 2500 as described above using the push pull screws,now you will find the allen screws holding the headstock down are very tight ,use a allen key that is in very good condition,you will need pipe on the key or hit the key with a copper mallet, never never hit a lathe spindle to adjust the head.If I remember correctly some of the sheet metal of the back tray covers one screw, now spend some time in doing the job properly,it took nearly 2 days to get mine right. First of all set the lathe level then clean up the lathe lubricate the ways and tighten the lock screw on the top slide and take any looseness out of the cross slide ,this is so that when test machining you are testing the accuracy of the headstock and not any errors in the rest of the lathe. If you have a gap bed make sure that it is fitting perfectly . The test bar ideally free cutting mild steel needs to be about 40mm dia and protruding about 7 inches out of the chuck to avoid deflection, now you only need two areas on the bar for test machining about 1 inch long, one at the end and one near the chuck,relieve the length in between so that the tool only has to cut for a total of two inches,this to reduce time and tool wear affecting the results,dont forget tool wear can cause taper turning a potential problem when you are looking for half a thou. Use a HSS tool really sharp with small rad and honed with a oilstone,do not use carbide for this job. For a test turn use about 150 rpm and a slow feed to get a good finish,speed is lower than normally used ,this is to reduce tool wear. Use power feed for turning ,do not do one test with power then the next one with hand feed,believe it or not you can get different results,I do not know why as its a V bed and should not affect the saddle travel, I asked a friend who was a seriously good toolmaker (ex Vickers) about my results , when he had run his business he had found similar results with Colchesters though he was looking for tenths. Unless the lathe is badly worn I would be looking for about half a thou taper or better over 6 inch , the larger end of any taper should be at the headstock end. Once set up to your satisfaction ,the tailstock will need adjustment as the headstock will have swung out of its old position and give an error when turning between centres.
If you have a new workshop with concrete floor ,check the level in say a years time as the concrete can settle.
The Headstock adjustment is covered in the Colchester handbook,get the correct book for your machine as screw positions and dowel pin can vary.
Best of luck you will need plenty of patience, p/s make sure your test piece is firm in the chuck and does not move, a slack chuck will give funny results, the four jaw may grip tighter.
|Thread: Gripping Drills in Chucks|
I had similar problems ,getting too old, I pressed out handles on a couple of jacobs chuck keys and made longer handles from silver steel,this way you do not have to keep looking for the piece of tube. If you cannot tighten or release a keyless chuck ,the rubber strap wrench with plastic handle sold at B & Q as a Boa does the job without damaging the knurling on the chuck. Another ,tip Jacobs chucks can be dismantled on a press ,after cleaning the internals and lubricating they work a lot better,Google jacobs chucks and there is a web site show how to dismantle them . It is noticeable that chucks used horizontally ie in the lathe get far stiffer with use than when used solely in a drilling machine ,it must be due to the soluble getting in the works. I now tend to store loose chucks morse taper up so that the fluid drains out .
|Thread: Colchester Bantam Lathe|
Colchester users may find this useful,some years ago I bought an all metric Student lathe,one feature which i had never seen before was a dial fitted on the saddle handwheel ,one rotation of the dial was exactly 25mm and it was accurate and useful. It was also fitted with variable speed and was short bed,it was a pain to use so I then bought a master 2500, which was imperial with dual dials,out of curiosity I checked the saddle travel against one turn of the saddle wheel, it moved 25mm so I came to the conclusion that they must be fitted with metric module racks so I took the dial off the student and it fitted my master, so I now had an imperial lathe with metric reading dial for saddle travel.I then sold the student minus dial, Most of the time I work imperial on the cross and topslide and metric on the saddle and it is so useful despite the imp/ metric mix. I then looked at my all metric triumph 2000 the rack was module so I went along to G & m tools and found a suitable metric dial which could be converted to fit the triumph hand wheel. I have Colchester bed stops but they are not reliable as they do slip and never use them now that I have saddle dials. One thing on my ex naval triumph is a 2ft long engraved sign stating "this machine is fitted with a metric threaded leadscrew" I have often wondered if someone made an expensive cock up confusing 0.2inch imperial with 5 mm metric pitch leadscrew. Going back to the student ,the mechanical vari speed and the phase converter was a useless combination ,I asked a machine tool dealer if he had experience with variable speeds ,his comment avoid if possible any variable speed powered by 3 phase conveters.
|Thread: square top Colch / Student|
Cross slide adjustment,I looked at my master 2400 today there are three socket screws plus a ball bearing type lubricator in the centre of the slide ,its about 10 years since I had the slide off so memories a bit rusty,I think two outer screws secure the nut and the centre one adjusts the nut, if its different just remove the slide and have a look how the adjustments work,I found that when removing the cross slide the screw sits in a long recess in the casting,and this recess has no drainage and of course it fills with soluble oil and if one of the more higher performance oils has been used it can corrode the feedscrew ,so I made a new screw as Colchesters wanted around £500 for a new screw and nut. And I drilled a drain hole in the casting. And if your Colchester has a hand operated lubricating pump on the front face of the saddle, while you have the cross slide off make sure the oilways / holes in the saddle and crosslide are cleaned out. Also due to space my master resides along a wall and it is a right pain to remove the cross slide and get access to the suds pump and clean out the tank.
Best bet is to buy a Bison 3 jaw chuck from Rotagrip,its worthwhile to also get a set of soft jaws they can be very useful. I understand that Burnerd chucks are now made by east european manufacturers but have retained their own jaw dimensions. I have 6 inch and 8 inch Bison chucks on my colchester master and they have proved to be very good,at one time eastern european chucks were very good value for money but their prices have risen a lot in recent years,but a lathes no good without a decent chuck ,
Unless you are broke I would not grind a lathe chucks jaws ,as if they are that worn the scroll and the slides where the jaws fit are also worn,plus grinding dust on a lathe does not do the lathe much good no matter how careful you are , I have an old 8 inch 3 jaw chuck mounted to a non swivelling base which can be bolted to my mill table ,ideal for holding round work for milling,the jaws were tapered so with feeler gauges I worked out how much the error was ,set up each jaw in a vice on my surface grinder and ground them true,the chuck then gripped work securely ,concentricity does not matter in this case and the grinding dust stayed on the grinder.
|Thread: First Time Milling Cutter Issues Help Needed Please|
looked at the posts,oh dear, putting 25 mm plate on a small mill is like this and then trying to cut with the side flutes of a 20mm cutter is not good practice and wont do the mill much good. Endmills always cut better on the end face ie the work would be set vertical on a stiff angle plate and the mill spindle would also be vertical, Speed about 250 cut depth about 3mm and cut half the width of the plate. probaly not enough room under your spindle, you could try a fly cutter mounted direct in the spindle which gives a lot more clearance under the head.ok you may say its a bit slow with a flycutter but it will get the job done . If you want to mill pieces of inch plate you require a horizontal mill with a sturdy vertical head with 40 int spindle.
I once saw demonstrated by a well known carbide tooling supplier ,an inserted tooth cutter with just two inserts milling an inch wide bar held in a vice in a bridgeport ,it cut at a very high speed and feed,no lubricant and produced red hot chips it was impressive particularly as the machine is only a light turret mill and the tooling was expensive,plus there is a considerable fire risk plus adjoining operators need protection, the point is it was face cutting not side cutting.
Travelling around many machine shops in the 1960/70s the operators favourite tool on the turret mills was the single point fly cutter on smaller batchwork , some operators loved a bridgeport as the controls are all to hand and the machine easy and quick to use particularly if a bonus system was in use . others preferred a lot sturdier mill for heavier cutting , though you did not see much side cutting with larger end mills,the shorter stubbier clarkson deadlock cutter was more popular. Also the clarkson threaded cutters in their clarkson holders were in widespread use as the end mills did not move as they were lock solid. I have collet holders on my large turret mill and universal mill but when I am cutting tougher steels the Clarkson auto locks are set up they are far superior as collets will let the cutter slip. The popularity of collet systems has increased with cnc and solid carbide cutters which have plain shanks.
|Thread: Chamfering on the lathe|
Chamfer tools as per the 90 degree pointed tool shown above with no top rake are ok for brass or cast iron ,to get a good finish on steel or bronze a chamfer tool cuts better with top rake, I use a Dickson toolpost and have a 6 inch long ,half inch square HSS tool bit permanently fitted in a toolholder , looking at the tool holder from the top,it is set parallel to the cross slide ,the toolbit has a 45degree angle ground right across the tool and top ground onto it, in this position small edgebreaks to wide chamfers can be machined on outside diameters. Now to machine chamfers on bores the toolholder is positioned parallel with the lathe bed ,the other end of the toolbit now protrudes towards the chuck this end also has a 45 degree chamfer with top rake,though more clearance on the front face has to be ground as it is boring type tool,so say a tube can have its outer edge and bore chamferred by just indexing the tool post through 90 degrees, The toolholder is marked with yellow tape so that it can quickly identified from the other dozen or so toolholders. I have used this method for twenty odd years on my Colchesters and it is quick and convenient particularly when earning a living at it.
When I trained as an instrument maker ,the use of files for breaking edges was more common than using a graver,the files were classed as super smooth and were either 6 inch and or long narrow 8 inch pillar files the tooth angle was normal . On the other hand a turner in a machine shop would not use a file ,he would be expected to achieve finish and size by turning , When I moved to a small toolroom cum model shop,it was noticeable that my colleague trained as a fitter and turner never used a file on a lathe but always used the power feed whereas I being an instrument maker nearly always fed by hand on mill and lathe on the smaller work,and even now rarely use power feed on my ton and a half mill if the travel to machine a job is less than 6 or 8 inches,you can feel what the cutter is doing and I cannot see why so many modellers want x,y power feed on small mills. z feed on the knee would be far more usefull but is rarely fitted
|Thread: strange taps|
Yes they are thread forming taps,they require larger tapping holes ,ie about 65% thread ,the threads are stronger due to the forming action,
Advantages virtually no swarf,less tap breakage ,high operating speed ,ideal for cnc work particularly with electronic solid tapping with pitch control,reduced cnc machine downtime and very few scrapped castings. needs high performance soluble oil with regular control of lubricant strength.
No good for any other work,they are a high speed production tool
|Thread: Stuart 'No.1' : a beginners tale..|
Setting a boring tool is difficult,one way to get over the problem is to bore the hole as close to size as you can,then turn the shaft to suit, or bore the hole to within a few thou and finish ream to size.When restoring stationary engines I always bore the cylinders and get a new piston cast and then turn it to fit the bore.When using a between centre boring bar first check the tailstock is in line with headstock,particularly if the tailstock has been set over for taper turning at some time,The between centre boring bar has the advantage that it bores a constant diameter,though a bore may be found to be tapered this can be is due to tool wear so when taking the final couple of cuts make sure the tool is sharp. In the past when this country did proper engineering long boring bars were mainly used on horizontal borers the tools held by wedges ,screws or taper pins,and the tools adjusted by a special depth micrometer mounted on a special vee block,the vee block was held on the boring bar and the amount the tool protruded from the bar measured by the micrometer, in more recent times adjustable tool holders could be screwed into the boring bars and a index ring provided micrometer adjustment and carbide insert used for cutting,they were very good but were limited to larger bores.
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