The AM11 LS Models pantos have a defect

The very beautiful AM11 LS Models pantos (mounted on their BB 16500) are sold as spare parts, which makes it possible to equip for example the Roco BB 16000. But these pantos suffer from a defect: their fixing device. It is in the form of a 3.3 mm diameter and 3.5 mm high metal cylinder moulded with the panto frame. It is drilled but not threaded, being supposed to receive a self-tapping screw.

Hum, maybe… The first time I tried to screw a panto, I quickly abandoned: the force that had to be exerted on the screw, while holding the panto could destroy the latter. So, I threaded the cylinder to ø 2 to insert a classic M2 screw. Annoying…

Central fixation of the pantos: not a great idea!

My opinion is that the central fixation of the frames distorts a loco profile. Moreover, with this very solid attachment, the slightest hooking can result in the destruction of the panto. So, I do not fix the pantos by their centre, but I glue them by isolators, quite simply. This frees the view from the centre of the frame. But for the AM11 LSM, it was necessary to remove this big ugly fixing cylinder.

A machining fixture

How to eliminate this cylinder without a risk for the fragile panto? This question led me to make a small machining support.

Diagram of the support

The panto will be “planted” in the support by its four feet (ø 1 holes), held by four Parker screws with washers (ø 1.6 holes). In the middle of the square thus formed, a large ø 12 through hole will make it possible to mill the cylinder from below. To limit the risk to the maximum, the panto will be kept folded as much as possible.

Support diagram

A 3 mm wide and about 3 mm deep groove allows to receive the main leg of the panto. The ø 12 hole is then enlarged with a file to improve the visibility of the work.