160mm chuck BAK PLATE

(SEPT 2006)

JOB DONE MAN!!

I bought a 160mm 4 jaws independent chuck but I need to make a back plate for it!!

At the bottom of the page there are the reasons why 4 jaws independent is better than 3jaws self centering....

...

let's start from a 800  * 200 * 20 mm plate of mild steel.... trying to make a round piece.... (picture shows the 600 * 200 * 20, after the cut of a 200 * 200 square...! )

the first cut at 200mm is done with the band saw and has required about 40 minutes... after that I tried to make few cuts with the slitting saw but without success...

so I started with the band saw that does the job very efficiently..!!! again, few hours to make 6 cuts...

cuts are done now it is turn to flattening to the max  (0.005mm) with the second octomill.

I want to be hones with you , and say that the 600w motor is SHIT !!!

I had hundred of hangs up and faults doing this step.

I was applying a 0.02mm depth of cut... the motor was making flames...

something is wrong, I really thing that a 2Kw motor is better that this stupid 600w weak motor..

anyway , after one hour I had this perfectly flat surface (this surface will be the one in contact with the spindle of the lathe)....

after few calculations and drawings I got the dimensions for the three chuck studs holes. I have make few lines with a compass on the flat surface of the piece and once positioned on the mill table I had to center the perfect spot with the laser...

and here I am making an 8mm hole.. with an end mill..

and here I am making an 8mm hole.. with an end mill..

and finally a M10 thread...

I repeated this for all three threads done.

Then I made a guide hole to start machining with the boring bar on the lathe. This hole is made starting from a 4mm and changing drill bit with 2 mm step ( 4 - 6 - 8..... to 20 mm shown)

cut three small bits (30mm) of a M10 steel thread rod and screwed them into the three threads, I am able now to clamp my back plate into the 3jaw chuck (close to the pension, soon !!)

with the laser I am aligning the out circle on the surface, moving the whole 3jaw chuck / plate assembly.

once centered, it is easy to create the 52.50 mm bore.

good job: the three studs are screwed with some locktite and now the backplate is ready to be mounted directly on the spindle.

the inner bore is a wee bit larger that the spindle flange, this allow me to center exactly the 52.50mm bore before tight the three bolts on the spindle back side.

ready to machine the FUCKED SICK NIGHTMARE CRAP  interrupted cut. , it is a bad job. I spent 3 hours to have few millimeters removed from the non regular side surface of the plate.

I really think that the interrupted cut is only for big lathes with big tools, not for small toys like a sieg.

I don't know I many days I need to finish this!!!!!!

;(

more work...and now the outer side is rounded as wanted... I spent about 5 hours to transform the multifaced part into a round 160mm part...

The sieg is not made to do heavy jobs. the motor protection circuit turn off the motor after few seconds of turning and also the saddle is not made to work with parts bigger than 120/150mm....

Maybe if I change the motor with a 2HP one I can improve the lathe torque.

The problem is that there are no gears for the speed. the motor is linked with a belt to the spindle and this means that if low speeds are used the number of HP becomes very little because the motor runs slow too...   the only way to improve this is to change the motor pulley with a smaller one, in this way to have 50rpm on the spindle the motor must run faster and more HP will be given..

For the every day work, with parts up to 50mm round, maybe the sieg motor is good.

The problem is the same as the X3 mill: no gears. POOR HP IF LOW SPEED are USED.

this evening I finished the plate:  turned the face and made the flange 130mm to go into the chuck body for about 7 mm. The photo shows the marking of the bolts spot before put the plate on the mill table..

alignment with the laser...

and drilling with an end mill 8 mm dormer 4 flute. the bolts are M8 * 35

wow! the backplate is made!! front view..., and back view

...backplate and studs mounted now....

mounted on the lathe ! the run out of the back plate is 0.00 (it was made directly on the spindle, that is why!!!!)

The studs are a wee bit smaller than the flange bores, this allows us to adjust the chuck to find a lower runout. I have 0.01mm now.

This chuck is a 4 jaws 160mm independent action chuck and this type of chuck requires to center the workpiece every time with a DTI. this is a longer operation that a 3 jaws chuck but gives me better results. more precision, repeatability and also possibilities to clamp square or strange shape objects.

and this is the Mr Lathe with the new chuck....and the old one...

chuck comparison:

( before ....and.... after)  :)