Sunday, February 17, 2019

Marklin bearings

Question: I noticed we are going to get the files to print templates for drilling out different motors for ball bearings.

Are there three difference sizes?

For DCM the bearing needed is 1.5mm internal, 4mm external, 2mm high.
For SFCM the dimensions are 2.0mm internal, 5mm external, 2.5mm high
For LFCM ?

Am I on the right track? 

Bent, you're on the right track, LFCM are the same as SFCM, 2.5mm x 5mm x 2mm. the LFCM has 2 versions but the drill procedures are the same the only difference between the 2 LFCM versions are the brush plate and the length of the armature shaft.


Ball bearings for ex-DCM are 1.5mm internal, 4mm external, 2mm high.
For SFCM the dimensions are 2.0mm internal, 5mm external, 2.5mm high

For ex-DMC motors with the plastic bearing, the job on the motor block side is really easy, because the replacement ball bearing is exactly the same size as the plastic bearing (4mm diameter, 2mm high). You can simply press the plastic bit out from the motor block (from the outside in) and then drop in the replacement ball bearing from the inside.

Hi, the answer is - it depends! Remember that there are different HEP motors out there.

The conversion is only that easy if it's a newer loco that came with the HEP motor from the factory, or a loco that had a DCM motor and was converted with the 60901 motor parts.

Hint - if you can see the black plastic bearing in the motor block, you can replace it easily, using a ball bearing with these dimensions: outer dia. = 4mm, inner dia. = 1.5mm, height = 2mm.

However, if the loco is an ex-SFCM or ex-LFCM (or an older ex-DCM), then there will be no plastic bearing, and the motor block would have to drilled in order to accommodate the ball bearing.

The ball bearing for the motor shield is the same size as for the gear box. For this, the motor shield must be drilled very carefully and centrically from 1.5mm to 4mm (some people drill only 3.9mm). I use a center drill (2mm-4.0mm). 

 Therefore, You can use a standard miniature ball bearing 4.0x1.5x2 (681ZZ) 

river6109 OfflinePosted: 06 February 2014 13:06:33
Sorry guys for not responding earlier.

Ball bearings: measurements: 4mm (diameter) x 1.5mm (bore) x 2mm (width)

sometimes the ball bearings fits nice and tight into the back of the motor block, if not again the tiniest drop of super glue has to be applied, I use a toothpick and smear the superglue around the outer side making sure there is no excess glue you than line up the ball bearing against a hard surface like the edge of an office or working table and pressing the ball bearing into the block, of course you have to remove the plastic insert first from the outside in and in such a way that the protruding cogwheel doesn't get bend or damaged, insert the armature about a minute later (from the outside and make sure it is in the right position (90° angle)by turning it.

Motorschield: all I'm using is different sizes of drills starting from a 2 mm upwards until I get to a size of 4mm. by inserting the drill bit into a Dremel drill and than rotating it by hand you will be in control of the position of the drill and its centre location using the drill from the outside and inside on several occasions or in alternative drilling attempts.
You may find there is a small amount of excess plastic material around the newly created hole take it off with a Stanley knife but don't damage the newly created hole.
you than can repeat the procedure by placing the ball bearing on top of the hole and see if you can press it in, if your attempts fail try to enlarge the hole with your 4 mm drill again by moving the drill bit forwards and backwards in a rotating fashion. the ball bearing should not fall into the hole and you can apply quite a bit of pressure to press the ball bearing into the hole but it has to be large enough in the first place (your own estimation) without deforming the brush plate. again make sure the armature sits in an 90° angle by placing the armature inside the motor shield and rotate the armature and see if it has the same on all sides, left,right, top, bottom, if not establish which side is slightly out and take the armature shaft on the other hand and move it upwards or downwards slightly and than again try if it is centrally located, if you do not make sure the armature is in an 90° angle by placing the motor shield over the armature shaft and securing it with 2 screws you will find eis no free movement available.

You also will find older molds and motor blocks are not as refined as newer ones, to give you an instance I just bought a motor block for a Hobby ICE train to add a second motor into my consist of 10 carriages and 2 motorized end units. done everything I've described as above and no movement at all. I then played around with only fasting one screw either the bottom or the top one and to my astonishment but not a total surprise the motor mold or its flat surfaces where the magnet lies on were not at an 90° angle, I've tried different methods trying to correct the abnormality but found there was only one thing to do is to pack the back of the magnet with some thin cardboard and I've picked a hole with a small screwdriver to let the screw through. it works excellent now.

So all in all be aware of it, some abnormalities can occur but you have to do your alterations precise so any variation in the motor block (most of us are not aware off) can be pointed towards one fault.

when everything has been achieved successfully you than can start assembling the whole motor, first your permanent magnet, than your armature, make sure it sits within the teeth of cogwheel and than push the motor shield onto the armature shaft, secure the screws on the bottom and top having done all this the motor should turn freely.

before putting everything together you can pre-solder the chokes on each side, add a ground solder pad onto the top screw.

always check your motor-shield and make sure the brush shaft is 90° angle or lying against the motor-shield

ne, you will not get the full sound quality by removing the speaker capsule, although the power pack is an excellent solution, (I've just ordered 10 of them) your tracks must be fairly dirty for this to happen with your shorter rail car(s). another reason for this to happen (dirty tracks) is over oiling motors (Märklin) as DC motors hardly ever need oil.
assuming from the pictures you've supplied, your rail car has 4 wheels (2 on each bogie) without rubber tyres and this should be enough to overcome such occasions having dirty tracks. how ever a power pack is an excellent idea to solve the other possibilities you've mentioned such as turnouts.

Over oiling is like a cat trying to catch its own tail, you're going the full circle = over oiling = dirt gets accumulated = mixed with oil = get picked up by wheels= gets deposited on tracks = cleaning tracks and the whole scenario starts again.

To overcome this re-occurring cycle is to fit ball bearings into your Märklin motors, this will preserve your brushes, armature and endless cleaning processes, cogwheels need some oil but very little, as little so there is no excess going onto tracks or ruining your rubber tyres. (rubber and oil don't go together) and we know what happens when oil gets onto rubber tyres. = they expand.

most 3/5 pole drum motors can be easily converted with ball bearings by removing the plastic insert in the back of the motor and placing a 4mm x 2mm x 1.5mm ball bearing into it (no drilling needed) the brush plate needs a 4mm drill bit and a steady hand and a drill with variable speed settings, so long you've got a good eye and you can hold the drill and brush plate in the right angle you shouldn't have any problems, a better idea would be to put it onto a wooden block drill some tiny holes through from the brush plate wholes into the wooden block, insert the screws which normally holds the brush plate to the motor and screw the screws into the wooden block, your brush plate is now secure and now start drilling a hole through the middle of the brush plate (armature shaft) making sure your drill position is 90° to the brush plate., and press the same size ball bearing into the brush plate. the result will be: no more oiling required, the loco runs quieter, smoother and better at low speed, all other motors with disk armatures would have to be drilled at the back of the motor block. drill bit 5mm = ball bearing 5mm x 2mm x 2mm and front bearing is the same as above., also when selecting ball bearings make sure they are sealed bearings and not open. (most of them are0