"Drilling" Stainless Knife SAW Rudder Blade??

[Darin Jordan]

I'm attempting to step it up for a SAW project I'm putting together and build a nice Stainless Steel Knife Blade rudder.

I have the rudder all ground and sanded and shined up and basically done, but I need to "drill" some mounting holes.

Definitely too hard for "standard" drill bits.

Anyone have any recommendations on how to get two holes into the mounting for these blades??

I'm all ears!

Thanks,

 

[Mark Bullard]

Most standard drills will drill stainless. It is a good idea to use new bits instead of used bits. The main think is to get the speed and feed right. The speed can be about anything but the feed has to match the speed. A fast speed needs a fast feed. If you try and do a slow feed on a fast speed it will work hardened the part and burn the drill up. And you will never get a hole in it outside of grinding it. Test with a few older bits on some scrap material to get the hang of drilling stainless.

 

[moparbarn]

cobalt drill bits, darin. slow speed, slow feed works best for me.

 

[glenng]

Cobalt split point drill bits. Slowest speed on your drill press. Feed pretty hard till you get it cutting then back off on the feed when the drill starts to break thru. A bit of drill wax or oil wouldn't hurt.

Hint-put the holes in before you do all the other work.

 

[toyotatruckin]

I used steel bits to drill 1/4" deep holes in the ends of ss for stubshafts with no problem and the bits lasted a very long time, like above said speed and feed are key (and good cutting fluid) --

 

[Steven Bryant]

try using Tuff Cut cutting compound or similar, it will make the job so much easier

 

[Al Hobbs]

Carbide bits are pricey, but that is the best way to drill stainless and titanium.

 

[RaceMechaniX]

Darin I buy a handful of #3 centerdrills and use cutting fluid. Apply constant pressure and pierce all the way through. The drilling will work harden the hole so I use a carbide dremel bit to open up.

TG

 

[lohring]

I made holes in hardened tool steel rudder blades with diamond burs. I used dental equipment, but a Dremel should work. Unless it's really hard, the above suggestions should work with stainless. A good cutting fluid helps.

lohring Miller

 

[Terry Keeley]

Try titanium!

Actually it's similar the way it work hardens. Center drill 1st, use sharp bits, cutting fluid and keep it cutting.

135* split point Co drills work best but not necessary for just a few holes...

 

[Bill Zawada]

I agree with Al Hobbs. Carbide and if you can find TAP-MAJIC for STAINLEES cutting fluid.

Low RPM and easy feed. Let the drill cut not punch.

Good luck,

Bill

 

[glenng]

Google Aircraft Tool Supply, PN 5000-16, PN 500-34 and PN 381. The drill bits are 135 degree cobalt split point and are very short and stiff. Usually center drilling is not required for these smaller sizes. The two sizes will provide clearance for the 4-40 brass shear screw and the 8-32 nut and bolt. If the blade you have is already work hardened you might want to start over with some 1/4 hard .050 S.S.

 

[Bill Gibson]

Cobalt, carbide, even Ticn HSS bits....slow, wet, cool, easy pressure....overheating ruins the day!

 

[Patrick M]

Darin-

I've used carbide burs similar to the McMaster #4284A24 to start the hole. Dimple each side until it breaks through using low speed and side pressure (not straight in), then open up with the proper sized drill bit using the correct speeds and feeds. It works on both high carbon and stainless knife blades. You may want to invest in more than one.....

 

[Darin Jordan]

Thanks for the tips and tool links, etc... Really helps!

I'll let you know what I end up making work... Need to find a supplier of stuff locally here, as I'm running out of time. SAWs are in a couple weeks (Nov 8,9,10)...