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Member postings for Nigel McBurney 1

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: Milling cutter damage - what am I doing wrong
15/05/2014 20:22:23

It would be helpful if the type/make of mill was stated and the spindle size,A mill with int 40 spindle would take cuts to full depth 5mm easily,a 30 int spindle should take a cut to full depth but if the mild steel is flat plate it can sometimes be stringy so a cut 2.5mm taken ,the centre cut should be no problem but if you try to climb mill the outer cuts then the mill can grab a bigger bite and damage the cutter , mild steel round bar always machines easier than flat drawn bms,black hot rolled is not tough just stringey and difficult to get good finish. Not knowing the machine ,it could be the machine is to light to take a 16mm cutter and the table is jumping about and breaking the teeth.

Thread: fuel tank
15/05/2014 19:41:49

As the tractor has a high tank a carburretter having a float chamber with a float to control the fuel level ,should be used,

Most hit and miss farm engines had a tank lower than the carb and had a non return valve on the fuel pipe,

Thread: Cast Iron Tips
15/05/2014 14:41:16

For a job like this use HSS toolbits ,with no top rake at a cutting speed of 80 ft per min, final cut should be about a thou. the fit of chuck to backplate should be a "knock" fit ie they should go together with a knock from the handle of a plastic screwdriver handle,make sure the chuck seats fully on the backplate and does not ride on the edges of the spigot, if you make a cock up and the chuck is a sloppy fit on the spigot ,dont worry set the chuck true with a dial gauge and really tighten the allen screws,the chuck will not move a unless you accidentally hit it hard with the saddle or toolpost ,

I read a lot on here about people always moaning about machining cast iron,perhaps our current generation do not like getting their hands dirty,they should have worked in machine shops up to the 1970s,some were like coalmines, cast iron machines nicely,no cutting lube ,though tallow was sometimes used for tapping and reaming.Though you did see slideways on well used machines that looked as if a big cat had used them for a scratching post .

I have only once seen soluble oil used in high volumes on cast iron (mill and lathe beds)on a futureistic automated machining cell where cleaning was impossible unless the line was stopped so the lubricant was used to flush away the swarf and it was very noticeable that there was no black dust anywhere.

Thread: Tool Post Material
14/05/2014 15:06:54

big problem ,if you grind holder plus tool,then replace it on lathe what happens to the grinding dust that will get behind the tool and on the threads of the screws of the toolholder. The dust will get onto your lathe slides and will soon wear out your lathe. When grinding your toolbits by hand always wipe any cutting oil of toolbit and then after the tool is sharpened wipe off any dust before replacing in the lathe.

Thread: Why did my Flywheel Wobble?
14/05/2014 14:59:01

I have often thought most flywheels have six spokes,and a awful lot of other castings/forgings were six sided yet most faceplates have two master slots set at 90 degrees making it easier for four spoke or square workpieces,though after a century or so Colchester did make six slot face plates by which time nobody was making flywheels. all the above are good comments though I will add some more, beware of workpieces that are stiffer than the faceplate overclamping will distort the faceplate. Holding work on stub mandrels can cause chatter problems as the bore on most flywheels is small relative to diameter. My method is mount three alloy blocks on the faceplate spaced two thirds up each spoke, then use three clamps on the spokes directly over the blocks,on heavier flywheels a further three blocks are mounted equispaced onto the face plate near the rim , three bolts screwed into the blocks are screwed outwards ,like chuck jaws , to just touch the inside of the rim.This helps to keep the flywheel in position and takes any radial strain off the spoke clamps . rough machine bore .o/dia and face ,sometime if the flywheel is spaced away from the faceplate the other face can also be machined .then relax the spoke clamps ,this allows any stress in the casting to be relieved but it remains in position ,held by the three bolts. Then leave as long as possible,tighten the clamps Finish by machining the rims and the bore last, on small wheels the hole should be bored a fewthou undersize and finish by reaming.

Use HSS tools for finish boring ,I have machined a quantity of flywheels from 6ins to 2 ft for steam and ic engines plus refaced rusty stationary engine f/wheels .

Thread: Poor surface finish
13/05/2014 10:33:48

I dont know how experienced you are,but I would suggest you try to find a really experienced turner for a second opinion ,if they cannot get good results then I think that you should dump the lathe on warcos doorstep stating that the machine is not fit for purpose, the tailstock height difference is a fault that should reject a lathe, I googled the lathe type and it appears tp have a vee and flat bed,a saddle traversed on this type of bed should not cause any of the deflection described particularly when traversing by hand .

refering to the comment on chatter and ringing when turning thin tubular shapes, this will occurr on any lathe,its the nature of the bell like shape, the work needs some vibration damping applied, during my aprenticeship I was making some 3 inch dia micrometer drums in brass . I bored them out ok but when turning the od and the taper where the numbers go it really sang and vibrated ,foreman showed me what was apparrently an old trick,fill up the Inside Dia with a thick greasy rag and ram it tight with a screwdriver handle ,vibration ceased, Of course depending on the job ,internal chatter on a thin bore is more difficult to cure ,a damping material can be clamped on the outside dia, or a larger piece of material used,bore to size,vibration should not occurr with the thicker wall material ,then turn the od to size.

12/05/2014 09:44:08

A lot of precision machine tools (lathes ,grinders ,jig borers )sit on three feet so there is no chance of bed distortion or rock. If a modellers lathe vibrates when sitting on 3 out of 4 feet ,it probably the lathe is at fault rather than the mounting, its usually the spindle assembly or chuck out of balance ,If the workpiece is out of balance then the operator should balance the work or reduce speed.

08/05/2014 10:18:24

Why should a new lathe require adjusting? as you have checked most of the commonly known faults have a look at the three jaw chuck, the severe chatter on the work is quite common on well worn or strained chucks where the jaws are gripping at the back of the chuck but not gripping at the front,of course it should not happen with a new chuck ,the chuck jaws may not have been ground parallel to the axis of the chuck. ( perhaps the far eastern makers have a rubbish grinder or operator)I have assumed that you have fitted the chuck correctly onto the spindle. First try fitting up the four chuck,mount the steel bar and turn at the same speed and feed and see what results you get . you could also try mounting the bar between centres and turning, though with 1 inch bar between centres speed should be reduced to 200/250.rpm.

If you achieve a good finish then its the 3 jaw chuck at fault, to confirm it place some paper between the jaws and work piece at the front of the jaw and see what the bar machines like. I have a 10 inch four jaw on a Colchester master, I bought the chuck second hand and for years it has only been used to hold castings and irregular parts,customer wanted a quick job so to save a chuck change I used the chuck to grip a 1.5 inch bar and got a result similar to the chatter in the photo.The work was only gripped at the back of the jaws, change chuck back to near new 3 jaw and back to normal .One may ask why have I got a crap chuck ,well I also have a Colchester Triumph which I bought at an ex gov sale and it came with a brand new set of chucks ,faceplate ,centres etc so I do have a lot of options ,though I find the Triumph hard work being well past retirement ,the Master is my preferred lathe.

Thread: What Size 4 Jaw Chuck
08/05/2014 09:30:32

probably the best option would be a narrow bodied Burnerd 200 mm four jaw with direct fitting D-3 mount,they can be found ,but their popularity results in high second hand prices, the narrow body and direct fitting reduces the overhang and resultant load .on the front of the spindle, New direct fitting Bison 200 mm fitting chucks are available but their cost has risen so much in recent years that they are no longer really viable for the average model maker,

Thread: Easy Machine vice location
07/04/2014 09:21:02

The company where I first worked had all the machine vices fitted with keys held by csk screws,one keyway run parallel to the slot the other keyway was at 90 degrees,this allowed the vice jaws to located either parallel to the table slots or right angle to the slot,the keys had to be unscrewed and fitted in the other keyway , if keys were looked after, location was within about one thou.Saved a lot of time.

Thread: Total newbe
04/04/2014 14:25:17

A six inch burrell single model based on an 8nhp prototype will weight about 2100 kilos a suitable trailer around a thousand kilos so can be towed by land rovers and discoveries,a road loco model will be another 500 kilos requiring a small lorry for transport, flywheel is up to 30 inches diameter ,a lot of the parts can be completed on a 7.5 inch c/height colchester triumph ,the flywheel and final drive gears,diff and winding drum will need a lot bigger machine , the cylinder block really wants a mill a lot sturdier than a bridgeport,.Why not try a to use a large engine as a prototype and try 4 or 4.5 inches to the foot,.

A six inch model is heavy ,needs a lot of storage space lifting equipment ,a big trailer,and will take an awful lot of spare time and skill.and cash lots of it. take time and really think about it before tackling such a large project,A lot of enthusiasts start a project but very few have ability to finish one.

Though I have the skill and a lot of equipment and by the time I was in the position to build one I had run out of years,so I bought a big one,had some fun but now I can no longer easily manage such a large engine though it is nice to have a big engine which two people can sit on easily ,bags of power,and a big easily managed fire.So if you must have a big engine do it now before age takes its toll

Thread: Cutting Speeds/Feeds
03/04/2014 20:47:48

80 to 100 ft per min on mild steels is a good guide for hss cutters,any faster and the cutter life is rapidly reduced,you can go a lot slower,it takes longer though the cutter life is extended,

Thread: Imperial fractions on drawings.
03/04/2014 20:33:41

I started my apprenticeship in 1958 as a scientific instrument maker,the drawings were all imperial,but our boss was a firm believer in metrication,he felt that continental optical instruments were finer as the use of one mm and half a mm was better than one thirty second and three sixty fourths,particularly for the widths of small steps and widths of knurls on items like eyepieces,when I completed my apprenticeship I was presented with a Roche Etalon vernier and I had the choice of separate imperial scales for internal/external readings or two scales metric and imperial for the external measurement and subtract the jaw width for internal measurement,the boss recomended that i have the imp /metric version as he declared that metrication would be with us within ten years,also he said never lend your vernier to anyone they are all to easily damaged, I still have it and it is superb no batterys to run down or false readings though its initial cost was a weeks wages for a skilled man, within a couple of years I got a desk job so all my tools went home for model engineering and how I wish that my vernier had the dual imperial scales. Most of my time was spent with metric drawings as a desk bound engineer yet I still prefer imperial , my home workshop has an all metric triumph 2000 and a master 2500 with dual dials and an imperial super 7plus two mills one of each measurement, Though I am familiar with both systems I am far quicker when using the imperial machines. The one item that more use should have been made of was metric drills in imperial days ,when working imperial the 64th step was often too large when reaming or requiring a small amount of clearance on a drilled hole,its a lot easier to use a metric set in regular 0.1 steps than the irregular steps in number and letter drills.

Science labs in scools and universities in the fifties and earlier were metric ,98% of our instruments which were mainly for school labs had metric scales, I learnt in all metric labs at school,imperial units at tech,and then when we as a country turned metric,the metric units were all different to the ones I had used at school,crazy.

Thread: Cutting a hole in Cast Iron
01/04/2014 19:37:07

what is your drilling speed?

Thread: Die Head Advice
29/03/2014 20:34:32

If the chasers are blunt,they have to be held in a special fixture to grind them,the lead in on the chaser is below centre,the centre part of the cutting edge is at centre height and the remaining part of the cutting edge is above centre,the reason for the this is that the last few thread teeth rub rather than cut ,and help to control the pitch when cutting longer screws,

The Coventry die heads were mainly used on capstan lathes.mounted on the 6 way turret.

Thread: What's wrong with T nuts? (compared to T Bolts)
28/03/2014 21:06:17

When I started work as an apprentice,1958, practice in our works was to use T nuts and their use was general in industry, the threads were were Whitworth 3/8 for small machines ,1/2 inch for medium machines, and I never saw a T slot broken as quite frankly we were trained in the use of machines and did not pick things up as we went along.In larger organisations trained tool setters set up machines for the monkeys just to wind handles and fiddle the bonus.

Where I worked ,a small company ,the owner kept an eye on things and was very particular about good workshop practice,He would not allow the use of long spanners,did not like studs and nuts on mills and bolts were used with t nuts on all machines. The whit thread is coarse so the jacking force is smaller than modern metric threads ,and the risk to table t slots was less, to select a bolt for a vice you just put the vice on the table making sure there is no swarf trapped then position the hole/slot in the vice base over the T slot and select a bolt that will hold the vice securely and not touch the bottom of the slot if it was close to the bottom then place a washer under the bolt head,then slide a t nut under the vice and bolt it down, the same method to select bolt length can also be used on clamps higher than the table which span the workpiece and a suitable block. If Tee bolts are used say to hold down a large vice ,then the vice has to be lifted up high and fiddled over the bolts with the risk of trapping fingers and trapping a bit of swarf between vice and table resulting in a ding in the vice and table,far easier with tee nuts. On small machines ie Myford cross slide ,to reduce the risk of damage long tee nuts can be made the full length of tee slot in the cross lide. with a row of tapped holes in the nut.

When I see photos on the web of various owners set up on milling machines ,its amazing how many have left spanners ,vice handles ,spare clamps on the machine table, our shop had plywood boards about 10 inches square which sat on one end of the table and and any tools in use had to be left on the board, What is the point in having precision machine flat tables and then putting rough tools on them which over period put dings and burrs on the table and so risk the accuracy of the work,

One point back to clamps, when holding work on the table if the work moves under the side thrust of the cutter,do not over tighten the clamps,and risk the tee slots or distort the table,use thrust blocks to take the sideways thrust,the block is clamped via bolt and tee nut, the face in contact with the table must be flat and smooth to avoid spoiling the table surface and place a piece of paper between table and block to increase the friction and stop the block slipping.

Thread: What did you do today? (2014)
28/03/2014 20:22:04

Hi Rick The tapered device in your photo is a machine reamer to ream tapered holes for taper pins, which were used a lot to secure collars to shafts.when this country did proper engineering, the taper used to be 1 in 96 (1/8 per foot) nowadays the more common taper is 1 in a 100, Taper reamers with straight flutes were for hand reaming the holes. Hand reaming the holes was time consuming,machining them was quicker ,the cheap way nowadays is to use roll pins which work but can be bl....y useless.

Thread: How do I know if this is Tufnol?
12/03/2014 20:00:31

Tufnol has never been cheap ,forty years ago I was a procurement engineer dealing with machining subcontractors ,any jigs and fixtures made by the subcontractors from Tufnol were very expensive.

Thread: Taper Mandrels
07/03/2014 19:42:04

The mandrel that gets the most use is a one inch dia on which I mount various milling cutters for cutter grinding, I bought this second hand,my smaller ones I bought new forty odd years ago I think they were Jones and Shipman another fine company gone for good when governments let our engineering industry go to the wall, I have not seen any new ones for sale,probably no use in modern production engineering now that wonderful things can be cnc machined with little second op work.

06/03/2014 21:10:43

Commercially made taper mandrels are tapered for their full length,hardened and ground,the work piece is usually reamed to size then pressed onto the mandrel, the taper is about 1.5 to 2 thou over length,and usually marked plus at the large end,the centres are recessed so that pressing or hitting the end of the mandrel does not damage the centre, they are generally used for between centres turning or used between centres of a dividing head on the mill,for light gear cutting etc , they can produce very accurate work but if buying second hand make sure that they are not bent. The mandrels usually have a machined flat at each end for the clamp screw of a lathe carrier.

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