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Harrison L5A lathe

"lathe section"
in this section I will go into a little detail about the various lathe parts, when I was in the process to buying a second hand lathe I wanted as much advice as possible regarding the different lathes and their workings, there is loads of different types of lathes, and they nearly all have the same functions, I found it irratating not been able to find a site that goes into detail around the lathe, as I said in my introductory page this website is designed for all us begginers and just people who are interested both young and old, I would like to show you around this lathe paying particular interest to the different parts,
if you own a Harrison L5A then the bearing refit section below may be of interest to you.

heres a fantastic website which gives all technical data for literally hundreds of different types of machines.

www.lathes.co.uk

Harrison L5A 11"swing, 5 1/2" centre height X 24" between centres, it has a single phase 1 1/2 h.p motor fitted, the lathe has 8 spindle speeds fitted with a headstock clutch mechanism and a clutch on the a,b,c 3 speed screwcutting/surfacing gearbox, all older harrisons operate with a noisey headstock, so if yours is noisey then dont worry, so is everyone elses!! this is due to the hardened heavy guage steel headstock and gear train gears that harrison employed on these older lathes,

these lathes really are a robust machine, capable of fairly accurate work, these are not toolroom lathes such as the Hardinge HLV range but not far off the accuracy, this lathe was built in 1963 and is still capable of taking 0.001" thou cuts repeatedly over 12 inches from the chuck,, i have taken 1/2" off the diam of a piece of solid round brass stock in one pass as an experiment with an engineering friend who stood next to me whilst he showed me round the lathe, he had used these lathes in industry many years ago and he assured me that this machine was well capable of doing a heavy cut of this diameter. the single phase 1.5 hp motor is a well suited power plant from a domestic suppy, but a 3 phase 2 to 5 hp motor and an inverter would be the ideal option, the speed range would be more usefull with infinate speeds obtainable with the inverter. i can only dream!!

the headstock showing all the speed controls,
the speeds are determined by the two levers at the top of the headstock, basicly the top left controls the slow speeds and the right controls the faster speeds, the large handle facing to the right is to control the back gear,
the spindle clutch is controlled by the large handle with the red knob on the top left of the headstock.

a document/plan holder fitted to the headstock, stops those grubby finger marks and coolant splashes getting onto expensive documents (such as £200 loco drawings) "I wish" it is easily readable from the front of the lathe, this one is made from a pc printers paper holder and a piece of perspex is covering the plan. my expensive plans cost me £2.75 "buy it now" off ebay! £200 quid for some paper! obviously they have too much dosh!

basic gear train
although i never got the full set of change wheels when i bought the lathe, im in the process of making the gears that i need, here you can see the basic gear train set up to cut 40 tpi, this also gives a fine feed to the cutting tool for a fine finish and is a good speed for roughing out, the roughing speed can be sped up by the gearbox A,B,C setting.
to the right of the top gear shaft is a microswitch which i am removing, this switch will be the electronic end stop for the saddle assy or(power off) switch for the motor

this is a spindle threaded with 6 tpi, with a 35mm bore running through the spindle. these spindles run on timken bearings which have been proven to have a long life,

"topslide and toolpost"
there are loads of different types of toolpost, some accommodate only one cutting tool where others can take upto 4 tools, i have the dixon type which allows three cutting holders, i tend to use the same harbour for roughing/facing and use the front harbour for boreing, i dont keep all the holders housed at the same time due to the sharpe cutters protruding,

"saddle and apron assembly"
the saddle/apron runs on the lathe bed and is kept accuratly in line by the "ways", this lathe has two "vee ways" machined into the bed, one in-lines the saddle while the other in-lines the tailstock or losehead as it is sometimes refered to, the cross slide is mounted at 90 degrees to the bed and gives motion to the top slide or milling table(if fitted)
the top slide is bolted to the cross slide by two bolts which allow the top slide to be rotated, the harrisons topslide can be rotated over the cross slide, which some lathes cannot do ,ideal for those awkward jobs, its pretty large topslide travel is ideal for turning a short taper.

the saddle is manually carried along the bed by the large wheel on the left, the handle to the right engages the saddle off the leadscrew when screwcutting, the surfacing handle at the very bottom moves the saddle and the power feed to the cross slide, the leadscrew or surfacing power cannot be operated at the same time due to a prohibiter been fitted. the big push/pull button in the centre is for either longditutional power or facing, the smaller wheel at the top moves the cross slide.

"3 speed A,B,C gearbox"
the gearbox gives three different surfacing/facing/speeds,
for screw cutting it gives three different tpi measurements in relation to the changewheels fitted on the gear train,

"forward/reverse control"
this forward/reverse switch enables the saddle/carriage and the cutting tool to move towards the chuck(forward) and vise-versa, if a long shaft has to have a lot of stock removed this enables the cutter to cut both ways, enabeling quick stock removal, if the right cutting tool is fitted.

"tailstock"
fitted directly onto the rear of the lathe bed, there are quite a few accessories which can be fitted to the tailstock making the lathe a more versitile machine, this one has a morse taper 3 barrel which the travel is around 4 inches, this is mostly used when turning between centres, and centre drilling,threading ect. always remember to lubricate the "v" ways and top of the bed, a replaceable tailstock is costly.
look at www.gandmtools.co.uk for a price for one of these!
incidently they stock loads of harrison lathe spares, well worth a visit and you get a fantastic service, this company is were i purchased the tom senior milling machine from. I found them great to deal with!

"thread dial indicator"
mounted on the leading edge of the saddle on a harrison, this dial indicates when to engage the leadscrew when screwcutting, there are numbers rangeing from 1,2,3,4 with 8 divisions marked on the face, if cutting even number of threads ie 2 4 6 8 tpi, engage the leadscrew at any of the 8 divisions, if cutting an odd number of threads ie 3 5 7 9 tpi, engage at any numbered divisions or if cutting threads of fractional value ie 2.5 tpi, engage at positions 1 or 3, this TDI info is for the Harrison L5A lathe and will differ from other make lathes,
see the book by L.H. Sparey "The amateur's lathe" for further info on the use on myford lathe thread dial indicators

"chuck guard"
you may think that this device is an unimportant waste of time! well! some lathe manufactures fit these guards with microswitches so the lathe cannot be switched on unless the guard is in the operating posision, and rightly so!
a little story that happened to me a few months ago, i bought a second hand 3 jaw chuck off this bloke who was selling this chuck for someone else, i fitted the chuck to the lathe and found it to work ok, untill i tried to part off a 1" piece of aluminium, 450 rpm, half way through the bar, and a loud bang! the chuck was whizzing round all over the gaff! the chuck guard did its job, it contained this heavy lump of steel from been thrown in my face, after collecting my nerves, i looked at what had gone wrong, the chuck back plate was still attached to the lathe spindle with the 3 securing bolts, this guy had put some sort of filler into the 3 threaded holes and re-taped with M8 bolts instead of M12 bolts, "this bloke who ever he is, is a grade 1 lunatic" also a stupid irresponsable idiot". "thank god for the chuck guard"
also the guard protects you when turning between centres, the lathe dog/carrier and its attachments stick out all over the gaff! easily catching your clothing, or give you a nasty bite on your knuckles, please use it if you have one and if not , fit one!

an easily "at hand" shelf for the lathe tools, note that the shelf is set to the rear of the lathe, the tendancy to reach over and get a tool when the lathe is running is a disaster waiting to happen, say your turning an odd shape like a crankshaft, the sharpe edges of the revolving work could easily catch your clothing so be careful

"fitting new headstock bearings"
ever since i bought the lathe i have been experiencing some slight tooling marks on the work nearing the chuck, with no more adjustment possible i decided to refit some new headstock bearings, although the lathe was made in 1963 I found the bearings to be readily available at the local bearing supplier, there is one discrepancy in the instruction manual regarding the rear ball journal bearing which is listed as follows:- item no;103 part no;LJ 1 1/4 descript;ball journal(XLS 1 3/4") this is also stamped on the journal as a XLS bearing when in todays bearing codes is a
LJ 1 3/4". im not too sure why this is and they didnt seem to sure why at the suppliers, im just putting it down to the changes over time!,, the LJ 1 3/4" ball journal is the correct fit.

firstly the gear cover was removed, headstock oil bath drained, rear spindle extension bar removed and the rear spindle locking nut and drive gear removed. both the front bearing racers were removed by gently knocking them out,

the rear ball journal bearing cannot be removed untill the circlip holding the rear gear has been removed and the gear brought forward, this gear is on a spline shaft and is easily edged forward with a small thin bar behind the gear and gently persuaded forward.
time to remove the main spindle bearing off the spindle, this timken bearing is knocked off the spindle pretty easily by placing the spindle in the vice jaws threaded end facing downward, there is a washer/spacer behind the bearing and its this that can be knocked down to remove the bearing, only gentle persuasion by the use of a copper hammer should be used to do this as i had no bearing pullers!

two punched marks
:
:
:
v

<------rear ball journal bearing,
LJ 1 3/4"

two punched marks on the large bull wheel that slides over the spindle correspond together.

the new timken bearings, then the bearing is fitted to the spindle.

the new bearing racers were pressed in by using a piece of wood butted flat on to the racer and gently knocked home, this method was also used to press the rear ball journal home.

the "B" after 387/382B referes to the timken bearing having a shoulder machined into the outer racer, this shoulder seats the bearing at the correct place in the headstock.

paper gasket--->

note:-
the "B" bearing

front timken bearing 387/382

note:- see the spacer that fits in between the two timken bearing racers, this is easily removed for cleaning, but when the spacer is replaced it should be placed that both the holes are at the approx 10 to 4 (clock) possision, this creates an "oil bath" for the bearings.
(this is very important)

all done and dusted,
this was an easy job to do, i did not rush the job and i thought about each step before i ploughed into it, great care must be taken when refitting the new racers as not to damage them, they have to be pressed in square without force, also when replacing the front timken bearing(387/382B)onto the spindle i had no bearing puller so the bearing had to be knocked on with care not to damage the precision shaft or the timken bearing as the bearing requires a fairly tight fit on the spindle, plenty of lubrication aided this.

there is a paper gasket in between the headstock and the bearing cover, which is hard to see if you dont know its there.

"BEARING RUNNING TEST"
after everything had been re-assembled, the lathe was run at slow/med/then fast speeds without the chuck fitted over a 30 minute period, seating the bearings in, also checking the bearings wasnt running hot or noisey(whiney), a test piece of mild steel, 10" x 2" was placed in the ind 4 jaw chuck and ""not"" supported by the tailstock, a series of light test cut was put on to see if all was ok! this lathe is 43 years old and (paint wise) looks to be showing its age, over the 9 inches turned, there was "zero error" for the test length of cut, an accurate machine for its age. to check for accuracy i turned a protruding collar at the chuck end and another at the end of the test bar, then measure both collars.

"clutch assembly"
the large spring takes up the pressure on the two bronze clutch plates, been revolved clockwise "takes off" the pressure and vise versa to make more "grab"
note the brass 10 thou sheet rolled around the plate runners, these plate runners do wear and cause severe clutch noise, the two bronze clutch plates wear too and the six holes get quite large creating even more noise, this is a cheap alternative to getting two new clutch plates made, insidently the six runners are "press/machined in" into the pulley and are not screwed in as i have found out.
also check the bearing that the double pulley wheel runs on, mine has exessive wear due to been old and without sufficient lub, a new one will have to be fitted soon.

Piczo