Unimat 3 Millinghead problem

[alex h.Participant @alexh-2]

hi friends!

i have a unimat 3 with collumn and millinghead.

if i want to adjust the head i got problems… left and right is 0!

but back and forward is 0.2mm off over a flycircle about 100mm.

i disassamble all… and clean all.

the column is straight!

the mount on the unimat 3 bed is straight.

i have no play in the quill or in the spindle.

i have the same problem with a proxxon ff400 mill.

the head is inclined forward.

any tipps or ideas?

what is wrong?

i adjust without motor!!

thanks

[alex h.Participant @alexh-2]

[JasonBModerator @jasonb]

Put some very thin shim in the top of the "V" that the column mounts into if it is the column that is leaning forwards.

Also check it with the motor in place as most of the weight is at the back and that may just pull things into line if the head is drooping on the column

[alex h.Participant @alexh-2]

hi jason.

if i put a shim in the v shape the failure stays after measuring again

i checked the v shape.. its straight

checked the column with bed.. its 90deg. to the slide.. 0.005mm off.

i checked this all on my big mill.. i screw the bed to the table and measure with a dial.

my big mill has 0 left/right and 0 front/back.

and the slides are off about 0.005mm its nothing.

twith this i have the reference that all is straight.

the hole in the glide part which is fitted to the colummn has no error.

i think.. when i adjust the head left right to 0 and then clamping him.. the clamping area is the problem. its all original

i test it with motor and belt.. when i connect the belt its only 0.1mm off.. when i disconnect its 0.2mm off.

[Graham MeekParticipant @grahammeek88282]

Hi Alex,

Your last statement gives a clue as to where some of the error lies. The loading of the belts on the U3 is quite high and this is taking up some of the play in the spindle bearings.

I would also want to check that the Quill is parallel to the column. Shimming the Column you say has little or no effect. This I would expect and leads me to think the Quill is pointing either towards, or away from the Column, (you did not say where the largest error was in this plane)

Resting the Column, and Mill Head, less motor on your larger mill table. Place vee blocks under the column if you have them or two good parallels and place clamps over the Column, but do not tighten. Adjust the mill head to be parallel to the table. Juggling the sizes of the parallels to be the difference in radii of the Column and Quill will make this a quick and easy set-up. Then clock the Column to be parallel with the X-axis and clamp. Move over and clock the Quill above and below the milling head. The Quill will need to be clamped and you will need to raise and lower your Z-axis. One, to get the high spot over the Quill and two, to clear the mill head casting when you traverse the X-axis.

Don't be tempted to clock a Silver steel bar in the collet or drill chuck for the above test. This will introduce further errors due to the type of work holding used.

While at this setting put a clock on the Spindle, at the Spindle nose and wiggle it to and fro. This will tell you what play is present. From what I remember this spindle runs in one long Oilite bush.

Regards

Gray,

[alex h.Participant @alexh-2]

hi!

problem is solved.

i machined 2 new bearingholder/adapter for 10x19mm bearings.

then i put in my er16 shaft .

checked with dial.

0 0 left right

0 0.01 front rear.

thanks

pictures will uploaded tomorrow

[alex h.Participant @alexh-2]

Album

this is my solution.

works fine!

it was only a test but i will made the bottom adapter new and shorter.

then i will made a second spindle with m14x1.

and i will extend the travel of the quill.. but i think… i make a complete new quill with more travel and direct bearing seats.

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