The Mad Lapper

An improvised reciprocating lapper.

The idea here is to try to lap the machining marks out of a large flat piece (200x200 mm) of mild steel. After hand lapping for about 30 mins, I figured out that completing the process by hand would take hours (even days?). So, I built this little rig to see if I can automate at least some of the process.

The power is supplied through a small 12V DC motor from Jaycar Electronics, with a planetary gearbox. The rotation of the motor is converted to a reciprocating motion via a linkage that I machined from scrap (and a coat hanger - the coat hanger wasn't scrap...). The steel plate is supported by a granite surface plate, on top of which I've placed 80 grit wet and dry sandpaper.

I'm not confident that the apparatus will produce a completely flat surface, but I'll see how it goes! :-)

Category:

Howto & Style

Tags:

• lapping
• reciprocating
• machine
• improvisation

[ironlionkalo]

are you using water on the sandpaper? it will keep it from cloging and also create a suction effect that will hold the steel down harder to the sandpaper

[DARKWINDOW77]

Interesting-

Did you indicate the piece as it makes it's transit to see if there is any slight lifting on the push stroke? I see that there are no weights to possbly counteract it this- just wondering

[J800613]

Are you using a granite layout plate as a lapping plate?

[rich22221]

ROBOTIC DILDO!

[Axbent]

@1kgsxrk7 convex i bet

[1kgsxrk7]

how did it turn out?