Search
 
 

Display results as :
 


Rechercher Advanced Search

Latest topics
October 2017
SunMonTueWedThuFriSat
1234567
891011121314
15161718192021
22232425262728
293031    

Calendar Calendar

RSS feeds


Yahoo! 
MSN 
AOL 
Netvibes 
Bloglines 


Social bookmarking

Social bookmarking Digg  Social bookmarking Delicious  Social bookmarking Reddit  Social bookmarking Stumbleupon  Social bookmarking Slashdot  Social bookmarking Yahoo  Social bookmarking Google  Social bookmarking Blinklist  Social bookmarking Blogmarks  Social bookmarking Technorati  

Bookmark and share the address of battle programmers alliance on your social bookmarking website

CONVENTIONAL LATHE AND MILL WALKTHROUGH

View previous topic View next topic Go down

CONVENTIONAL LATHE AND MILL WALKTHROUGH

Post  Admin on Wed Feb 01, 2012 4:16 am

watch free videos for the subjects in the walkthrough

LATHE :

properties :
x by y : length of center to bed by center headstock to tailstock
belt or gear driven.
through hole ( where the material is held ) diameter.

SAFETY

ear plugs, gogles, work shoes ( with metal on top ), workplace ventelation, use of resperator, no accesories like a watch, no long hair,
no long flapy sleeves, mustn't touch moving parts. keep unrelated part like a chuck key away from the machine while running it.
if needed remove chips while machine runs only with long players, use low level air hose setting ( 15 - 50 psi ) to remove chips.
if the machine has no auto coolant system, then keep hands away from the machine while adding the coolant.
after finishing work wash hands thoroughly with warm water, especialy if they contacted coolants and lubricants.

SIDE TOOLS :

horizontal band saw with a coolant system : fast way to cut stock to size before working on it on the machine.
it is used if the material is more than 2.5 times the size of what fits inside the chuck.

MACHINE

check across lathe ways (betwin head and tailstock) if the lathe bed is leveled with a machinest level, which uses an air bubble :
if not leveled use lathe screw, should be near lathe's buttom or use an aluminium shim.

align tailstock to headstock

1 use tail's adjustment screw to align its witness mark ( center it )
2 use a live center on head and further align centers to tail according to look
3 coax indicator into head collet, touch its tip to the tailstock in 3 - 9 6 - 12 oclock position and align tail so that the coax indicator
shows a constant #

lube machine daily by pooring lube into lube holes

if the machine uses a belt, use the belt tightening lever to add tension
change the pollys on which the belt sits to vary the spindle speed

can add dial indicator to gage machine depth progress ( x+- )

caridge power feed klatch to enable auto feed
feed cross x-+, y-+ Neutral to disable power feed

halfnut lever - enables thread dial to time start power feed to thread


METALURGY

get your steel castings from your local steel suply house, also ask them for a catalog or manual or stock list ( steel and aluminium catalog).
you can also consult with them what material to use for a designated part.

STOCK HOLDING

clean inside of headstock with a rag.
stock holding devices
COLLETS : hold small stock pieces, in headstock put collet nose in it the collet in it the work piece, from back of headstock collet sleeve atatch collet
closer system on sleeve.
when the collet is sucked in the headstock it tightens the grip on the workpiece.

CHUCKS : mount on head stock using a cam lock key, then after putting the stock ( material ) in them tighen using a chuck key on the chuck it self.
you can put paper betwin the workpiece & the chuck to prevent jaw marks, also keep the chuck clean before use.
3 jaw chuck : used for facing cuts and low tolerance part making, not very accourate for other cuts.
4 jaw chuck : used for all works. after inserting the material and center it as you see, then use a dial indicator to locate the maximum side protrusion of the
workpiece open a little the buttom jaw and tighten the top jaw so that the dial indicator doesn't vary too much when rotating the work piece. now the
workpiece is centered.
6 jaw chuck : more accurate than the 4 jaw.


CUTTING SPEEDS

see cutting speeds for common metals ( a chart of material ( and class like bernel hardness high speed steel cemented, carbid,
coated carbid and fpm ( feed per minute) )
rpm = revolution per minute ( spindle speed )
rpm = (fpm * 4) / stock diameter in inches
choose the spindle speed closest to rpm but if you get vibrations from the machine or you do a finish cut or you get long or blue chips or
much smoke then slow the speed.
lube + cleaning
cutting fluids :
remember to use eye protection
castrol moly dee tapping fluids
wd40 : mostly for aluminium
mobile mix with water for coolant pump
see cutting fluids catalogs.

DRILLS

remember to cool the tool in water when making it :
making a toolbit out of a little piece of high speed steel : take belt sender with its little table alighned 6 - 8 deg to the belt, sand the piece's sides :
6-8 deg betwin the toolbit's point and the belt and 6- 8 deg from perpendicular to the belt and to the side, finaly send the top of the toolbit without
sending its point. this tool will be used for facing, side, chamfer cuts. after that you can send the tool with figner belts to sharpen it
(finer finish then high polish finish sand belt), and chamfer a little the point to make it last longer on the lathe, or radius the point for finish cuts. the 2
sides of the standard tool bit are called side relief and lead angle. if the toolbitis made of carbid grind it to restore tool sharpnes then you can
fine finish with a diamond wheel. the grind maching can be restored using a stone bracer.

cutoff tool : performs shoulder cuts of cut offs
akhiles chuck : atatches on mors taper on tailstock & used to hold drills
hole : tail stock + akhiles chuck + center drill, then drill.

center drill

bore : widens hole using a boring tool ( see above )
chamfer : use toolbit and angle it using the tool holder or compound rest deg set.
knurling : use lantern tool holder + knurling tool. to remove chips brush againt the lathe stock spin with an acid brush ( away from the tool ).
rimming (in back gear) : very accurate, done with rimmer after hole.
taping : done after rimming, it makes a path for a screw. atatch tap guide to tailstock + tap to guide, advance 5 spins in 1 spin in reverse.
cone : use compound rest at a 60 deg angle

TAPERS :

a taper is used, among other stuff, to hold chucks, that hold drills. a taper gets fater across its diameter
common tapers :
morse 0-7 0.598 - .625 (x) x = taper per foot
jarno 1 - 20 .6 (per foot)


cutting a taper using the compound rest :

taper per foot div 24 = tan of compound rest angle to be set
use a toolbit.
checking the taper after cut :
place dial indicator on compound rest and move it 1 inch across the taper the dial should show .6 variation for the jarno taper, for example.

THREADING

quick change gear box for threading :
tumbler1 A tumbler2 X(threads per inch) + feed rate
B
C and so on
disengage tumblers for no threads to keep machine health

threading is done in back gear ( to engage back gear remove the gear pin and manually rotate the spindel before using the machine.

the thread tool is made like the toolbit, but check that it has 60 deg with a threading fish tail, and surface the top without creating a rake like in the toolbit.
first use a part off tool to cut a shoulder at the end of the yet uncut thread. after reaching said soulder at each threading pass stop the power feed
(using the feed clutch) and take the toolbit back and to the thread start.
set the compound rest to the deg of the thread div 2 - 1 ( for 60 deg threads 29 deg )
set cross feed dial to 0 when the tool just kisses the work piece.
align 60 deg toolbit to a fishtail's (that is perpendicular to stock) side groove, set threading tumblers ***, cut using power feed on dial ***
each time a deeper cut.
start the power feed when the thread dial is at an integer for odd threads per inch, integer or any half number for even TPI, and
at a constant selected by you integer for 0 < TPI < 1.

PICKING UP A THREAD : manually place cutter in thread way , and start power feed as you would mentioned above.

thread classes 1 - 3 3 = very fine
type of threads : A external, B internal.
UNC ( unified national coars ) diameter , threads per inch for example : .25 , 20
UNF ( unified national fine ) diameter , threads per inch for example : .25 , 26
UNEF ( unified national extra fine ) diameter , threads per inch for example : .25 , 34

the threads per inch can be measured with a pitch gauge.

minimum thread depth = .75 div threads per inch.

thread of 3a would be used for warships for example.

getting 3A thread depth :
.57735 \ threads per inch = thread wires to use diameter = wd
3wd + thread diameter - (1.5755 \ threads per inch) = X
place thread wires on thread nad encase with caliper. the number the caliper shows has to be x.


internal threading : same as regular threading but in holes

filing : done on finished part, olace a towl on the lathe ways, while the lathe runs file against the spin to remove bore.

holes in odd shaped parts :
making a hole : dye the part, mark the hole using the caliper teeth, make hole with a hammer & a center punch, place the part in a
4 jaw chuck, center it with a dial indicator on the tailstock and its needlel in the hole, use low speeds ( rpm < 1000 ) see hole above.


MEASURING

depth meter : close with rotator then with top wretched stop ( hear it click )
digital caliper
micrometer : 0.25" per graduation + thimble # + back # that lines up with another # for the 1 \ 10,000ths

CONVENTIONAL MILLING

SIDE TOOLS :

wooden or leather table protectors, to be placed on the machine table to the sides of the stock holding clamps.

step clamps.

MACHINE

align spindle perpendicular to table by mounting a dial indicatorand 0 fluctuation for north west east and south positions by adjusting the spindle head
with a wrench
when buying a 2nd hand machine verify it hasn't much scratches : on the table, spindel, levers.

lube machine daily by pooring lube into lube holes

PREPARING A BLOCK :
cut all its sides with an endmill, the top is faster cut with a fly cutter. and get the block to size if needed.
debore edges with a file.

STEP PULLY SYSTEMED MACHINE :
engage back or fast gear lever, then engage speed lever and put the belt on the proper speed pully wheel.
click on off reverse to work spindle.
nowadays some machines are button only activated.

the machine x,y axis are lockable using gibs. the z axis has a screw level lock.

CLAMPS :
the clamps are to be aligned to the spindel using a dial indicator.
odd shaped pieses can be held using also leather.
putting cards betwin the clamps and the stock increases accuracy.
chuck + collet
put collet in spindle, spin draw bar ( screw on top of spindle ) to suck collet in place, insert drill or drill chuck, tighten screw.
cutting speed

FEED RATES

rpm ( rounds per minute ) = fpm \ (.26tool diameter)
fpm - feed per minute from chart for material and cutter material.
if however you get noise or blue or long chips, then decrease speed.

maximum feed rate ( measured in inches per minute ) = # of drill flutes * rpm * material chipload ( from a machinery's handbook chart)
2" per minute for example = 10 spins of x or y or z of the drill per 1 minute.

DRILLS :

coax indicator : used to locate centers of holes.
end mill : cuts to its sideways and downwards.
using a vblock an end mill chamfers the material, a pyramid can be made that way by doing 4 chamfers.
fly cutter : very fast way to cut the top of the stock material
radius cutter : cuts a radius on stock edges
chamfer tool : cuts a chamfer on stock edges
slot mill : cuts to the side after an end mill slotet a path for the slot mill's uper area.

SPECIAL TOOLS :

rotary table : enables circle cuts and polygon cuts. get the table center coordinates with a coax indicator, or dial indicator if you are cheap.
universal dividing head : like the rotary table, but it enables work on long cylindrical stock ( cutting across it ), and it is less accurate than the
rotary table.

study

_________________
kurayami no kagi
avatar
Admin
Admin

Posts : 58
Join date : 2011-08-01

View user profile https://yotamarker.justforum.net

Back to top Go down

View previous topic View next topic Back to top

- Similar topics

 
Permissions in this forum:
You cannot reply to topics in this forum