#1 MAHO SK250
home back

Buying

This is the Maho Sk250 as I bought it. It was on sale on ebay, but I noticed it to late. The buyer was willing to resell it to me. It came from Germany Remscheid. A tag on top stated that is was owned by:

Dr.Ing.h.c.F.Porsche KG.
Nr. 30031

The main reason to buy it was the low price and the included shaperhead. The outside looked awfull, the inside was unknown. Beside, I bought on Ebay another item by accident which had to be collected personally. This location was quite near to Remscheid so I had to make the trip anyway

Hauling

For the ones interested in the hauling: I placed it on a flat trailer that was hooked to an normal sedan (net. weight 1500 kg, max. trailer weight 1350 kg). My biggest concern was the forward sliding in case of heavy breaking. I placed 2 pretty heavy straps to the back to fasten it (one at the top and one in the middle). There was one strap to the front as a counter pressure. To avoid sideward sliding i placed one strap around the bottom. It was a 300km drive home. One even roads no problems at 90 km/h ( I once drove 110 km/h without noticing it), on uneven roads the trailer behaved bumpy and I had to slow down to 70 km/h. The machine was loaded onto the trailer with a chainhoist (lucky me, not bringing a closed van) The machine was unloaded with a forklift.

Specifications

 

Machine: MAHO Universal-Werkzeug-u.Gesenkfrasmaschine. SK250

Manufacturer: Prazisionsmechanik u. Maschinenbau Mayr, Hormann u. Cie., K.G. Pfronten-Steinach/Allgau

Machinenumber: 1388

Max. cutterdiam : The speed conversiontabel goes up to 90 mm diam

 

X-travel 380 mm (360 mm on scale)
Y travel 180 mm ?
Z travel knee 300 mm ?
Spindle 70 mm ?

Motor:
1400 rpm 2,0 kW
700 rpm 1,2 kW

V-belt motor: Optibelt VB SC plus
type: B1440 Ld/17x1400 L1 B55

vertical spindle speeds:
1400,1060,800,710, 600,530,450,
400,335,300, 250,224,190,170,125,95

horizontal spindle speeds:
1000,750,500,375,560,425,315,236,
180,132,280,212,160,118,90,67

Inspection

The inspection of the "new" machine gave some unpleasant results. In short: the whole transmission is a disaster.
-Drivebelts: are missing and wornout, belt pullys damaged, splines missing.
-Main gearbox: two gearing wheels very bad, the rest a lot of freeplay.
-The backgear: gearingwheels acceptable, but the shifting mechanismen was fiddly.
-Headstockgearing: completely worn out.
-Horizontalspindle: rather good.
-Verticalspindleunit: casting broken at clampingpoint (verticalspindle cannot be clamped).
-Collet: little cracks around the entrance.
-Wiring: fiddly (hazardous at connectionpoint with the motor)
-The vice is ot an original MAHO-vice
-The ram appaers to be in acceptable condition

Less important defects: handwheels broken and ugly repaired, tabletop very scorn, big chunk broken out of the front.

There has been an X and Z powerfeed in the past, but most of it is removed.

Conversion
Instead of replacing the whole of the bad transmissionline, the thought has crossed my mind
to replace the transmissionline with only an VFD-controlled motor on the top.

 

The new transmission line can connect directly to the driveshaft that's already present at the side of the headstock.
The original belts are removed in that case.


Spindles -dimensions
axis scale measured max.
travel
usable
travel

spindle
diameter

spindle
length
X axis 340 mm 355 mm 350 mm 22 mm 860 mm
Y axis 180 mm 225 mm 200 mm 18 mm 320 mm
Z axis 300 mm 322 mm 310 mm 25 mm 500 mm
spindle - 68 mm