Manifold Spacers
 

Another interesting project - machining manifold spacers for aftermarket fittment of side draught carbs. Material: Tufnol - electrical grade 8mm thick and 1.6mm cork gasket.

Procedure: screw tufnol sheet to table with two layers of cork gasket material clamped underneath the tufnol, machine the holes, insert screws with washers in the bolt holes securing the job to the table, machine the outside. All cuts three passes, two in the tufnol and one for the two layers of cork.

Feed speed: 1200mm/min
Plunge: 600mm/min
RPM: 18000.
Cutter: Solid tungsten two flute slot drill



Lessons learned: slot drills cut tufnol better than compression spiral router cutters (regarding finish), slot drills need a MUCH slower feed speed than compression spiral cutters, Missed steps from having the feed speed too fast can NEVER be missed - loud bangs and much clattering :eek:. Slower feed speed results in almost no chatter (if it is there, its very difficult to see or feel)

Nice work Alan,

Thanks for sharing.

Awesome, nicely machined parts.

Wayne

Alan,
That is a really nice looking finish on the rounded parts! :)

Nice job Alan...and that with ungeared motors. Maybe that is the reason I am happy with my machine...I go nice and slow on my jobs. Keep the pictures comming.

The radius on the manifold is much smaller than on the hand-mirrors, that gives less chatter, because there is less time spent going at a certain angle - the system doesn't have time to get into resonance. The long slow curves, or just a certain angle across the table, combined with a certain feed/spindle speed is what s gets the resonance going. For some jobs it actually helps to increase the speed, but that is rare.

Still nice gaskets though! There are guys in Cape Town who make and sell gasket kits on a big scale. I started looking at offering a CNC service to them, but realised that it would be slow business with lots of effort put into each job for programming and hold-down. But you have some nice samples that you can show around. :)

Alan,

Beautiful work. Just to make sure I understand, would you post a picture of a "slot drill". I have to machine a bunch of different plastics and I am going to experiment with "O" flute bits and I'll check out a "slot drill".

Thanks so much.

http://en.wikipedia.org/wiki/Milling_cutter#Slot_drill

Will grant that the name "slot drill" is probably a British variant. Others could say it is a common "end mill". But the tip is such that it can drill - cuts to the center.

The Belin Spiral O bits (there are other manufacturers as well) are very good for plastic/acrylic/nylon and give a very nice finish, they are a bit pricey but your costing should take that into account.

Had to post a picture of the flower box thing that my wife wanted. She does the painting.

Attachment 3922

Slot drills are for drilling slots, they cut both sides (of the slot) as well as have the ability to plunge. End mills are for milling ends, as the name describes, they are used to cut one side only. There is conventional milling which feeds the mill against the rotation of the mill. Climb milling is where the feed is with the rotation. Conventional milling is for roughing and climb milling for finishing.

http://web.mit.edu/2.670/www/Tutoria...scription.html

Regards from Nexon CPF Yemen.