Toz part search

[kobbie]

Hi, i am searching this part of a toz , is this available on Europe?

Kobbie

[mjmarz]

What a joy to find this drawing on the site. One of my parts guns is without this particular piece. I can only imagine that the wait for the part, if available at all would be months. Armed with this, fabrication seems much easier. Thanks very much.

[Guest]

http://www.larrysguns.com/Departments/R ... OZ-35.aspx

^ This is a dealer in the US who maintains an inventory of TOZ parts.

Do you know the name of this part?

[kobbie]

Is this a Toz 35 or a other one?
The part that is broken is of this pistol.
Type is Toz.



Kobbie

[gunnery]

THATS NO TOZ 35 its a MC55 http://home.planet.nl/~bandamh/Schermer ... se-vp1.htm
http://www.geocities.com/pistoleer2001/Evolution.html

[toznerd]

You need a new hammer for your MC-55. It doesn't seem like a part that would fail, but when the pistol was shipped in a box with spares, a hammer, mainspring assembly, and 2 firing pins were included. Unlike the TO3-35 and Hammerli free pistol line beginning with the 150 series that uses a sprung striker, the MC-55 uses a firing pin and hammer arrangement, like the older 100 series Hammerli free pistols. Good luck finding spares, as they are getting extremely rare (especially in the Americas.) You might just as well find another MC-55 and use one as a source for spares. Of course, a fair machinist can fab one up a in a few hours, since you have a drawing.

Good Luck,

toznerd

[kobbie]

A new hammer will be bild.
The question is why it always breakes on the same place.

Kobbie

[william]

Could you please indicate on the drawing where it breaks?

[kobbie]

I suppose that material would be better in stainless steel.

Kobbie

[toznerd]

I'm only guessing that the part is mild steel that is tempered to give it better surface wear characteristics. A better material should work, but makes fabrication a little more difficult; not that we would care, its a one-off part, and not hindered by production costs over a run. I would also say that the 1.5mm radius (where the break, more than likely, initiates) could be modified or eliminated to give a slightly great section. Also, when releasing the hammer spring tension, use the breach lever to catch the hammer closest to its lowest point. A cartridge acts as a buffer to absorb the shock of the hammer when it falls. Dropping the hammer on an empty chamber will greatly increase the stress on the hammer, as it sharply decelerates (stops).

Keep us posted

toznerd

[kobbie]

Thanks for your reply, to be continued

To other users of this forum feel free to give your opinion too

Kobbie

[Shooting Kiwi]

I am not familiar with this gun, but am familiar with basic engineering and machining practice.

From your diagram, it looks like the break occurs at the base of the bit sticking sideways(?) from the main body of the part, and where there is a notch in the profile of the body of the part. A fatigue crack, presumably.

Good engineering practice dictates that where abrupt changes of section cannot be avoided, the transition should be a curve, rather than a sharp angle. Sharp angles are 'stress-raisers' and are where cracks are most likely to start.

If you have to make the part, is there room to modify it a little, so that the internal sharp corner can be given a radius? It would help to radius all external corners also and to polish out machine marks. Unless you know the properties of the stainless steel you want to use, I would suggest you avoid it because of the very wide spread of mechanical properties among the stainless steels. 'Gauge plate' (sometimes called 'ground flatstock' - it's an oil-quenched, heat-treatable alloy steel, used for making gauges, jigs and other precision parts: it does not change dimension significantly, and is unlikely to distort on hardening.) is a very useful material for small parts like this, combining toughness and the ability to be heat-treated for hardness. I don't know what it would be called where you live.

Hope this helps.