QCTP SUPER STIFF BASE
(DEC 2007....)
Yo men... I am just so tired about the crap sieg topslide compound. Every time I machine something my tool start to bounce on the workpiece because there is a small amount of (non fixable) play in the sieg top side.
I can’t make any knurling, I can’t get any heavy pass, I can’t just work.
Ys, the only good thing about the top slide is that It allows machininig of inclined and irregular pieces, but in my small lathe story only 5% of time is spent using some strange angle on the topslide.. so...
let me remove it and create a super stiff base for my super strong ALGRA QCTP.
let’s start from a billet of steel, about 12kg.......
..work done man
the DNMG tool is the best I have to get a good surface so I am using it now to get the perfect 18,00 mm for the first section, and as visible I got already a nice finish on the outer bigger diameter of the piece..
12 mm dril bit to prepare the way to the dormer M14 tap...
and then I am machining the marks of where the threads must go.
Don’t use the drill bit without a “drill sitting” because if you want precision this is the way of getting it!!
..ok, holes are drilled with a 4.2 mm drillbit, now it is time to tap, again with a dormer M5 tap.
let’s tap!!!!
my nice band saw is cutting off the workpiece from the main billet of steel now...
I can’t use any lathe parting off blade because the topside compound is not strong enough to allow me that!!!!
the diameter of the workpiece is 80mm, and my lathe is just no able to machine smooth without block itself with the circuit protection for over amperes..
The moral of story is that I am gonna upgrade the lathe with some extra pulley to get more torque at ow speed.
This 80mm piece, with the Kennametal insert must be machined at 135 meters per minute , which is about 540 rpm, that equals 1/5 of lathe max power that is 800 w at 2500 rpm..
when the workpiece is smaller,... say 20mm, the lathe speed must be 2170 rpm to get same 135 meter per minute.
so basically this lathe is made to work on pieces smaller than 25-30 mm I would say.
Of course I am talking about using carbide inserts.... with HSS ttools all the speeds must be slow down 10 times!! so the lathe is no useful because there is no torque!
anyway, let’s go on......with the turning..
this is the result of removing about 62 millimeters of steel..... because the needed center clamp must be 18.00 millimeters dia.
The VBMT tool is used here to downcut a V hole to remove the contact area at the base of the 20mm cilinder....
let’s go on the mill, after a super precise positioning of the workpiece, I had drilled 4 holes plus two side 8mm sittings.
Before all this, I had to make flat the surface cut by the band saw. My seco OCTOMILL is the way to get flat surfaces!!
the other side of the workpiece must be machined to get room for the bolts heads... using a nice DOMER COBALT endmill 10mm..
time to work on the lathe cross side compound now... I am aligning it with the DTI, at 0.01 mm
some work on the lathe to create two 8*32 mm pins, and this is all... the work is completed.
the two pins, are used to keep in place the turret base, with a perfect 90° angle with the Z axle of the lathe. the top of the turret base is equipped with another 8mm sitting, that match the turret pin to get the parallelism.
the base in fixed, now it is time to install the turret
so, moral of story, mt turret is always perfect perpendicular with the lathe Z axis, but can me moved easly ouf of the 90° by pulling up the black pin....
easy!??
turret installed!!!
I have tried to machine some heavy cut and the lathe is just so strong now, no vibrations!!!
the top side is crap!!!!
Hey, this modification is a MUST if you have a CNC lathe!!! throw away your topslide!!!
