Drilling pushrod woes ..

bkervaski · #1 04-02-2018, 11:18 AM

I'm down to installing pushrods into my wings and then I get to close them up, take them to the hangar, and final assembly!

This weekend, drilling pushrods and subsequently getting a rivet in them straight proved to be quite a challenge.

Here is a pic of my .. ahem .. practice piece. I can't keep the bits from roaming from one side to the other. I've tried short and tall bits and have tried scoring the location with a punch, etc. No luck, every other attempt to drill wonders off to one side or the other.

There has to be a better way to drill these things .. hoping I'm missing something simple.

I have the press set to its lowest rpm.

Any advice appreciated!

TShort · #2 04-02-2018, 11:22 AM

One thing I have found is to use a bit that is as short as possible, and insert it fully into the chuck ... that looks like a 12” bit, and those things will wander all over, especially in #30 and #40...

rv7charlie · #3 04-02-2018, 11:22 AM

Here you go:
https://www.google.com/search?ei=kGb....0.CceTZJ1i2T0

You can get a usable set from Harbor Freight; fine for drilling aluminum.
edit:
https://www.harborfreight.com/center...-pc-60381.html

Center punch, then use the smallest bit from the above set to start the hole. Finish with the correct numbered bit.

bkervaski · #4 04-02-2018, 11:25 AM

Quote:

One thing I have found is to use a bit that is as short as possible, and insert it fully into the chuck ... that looks like a 12? bit, and those things will wander all over, especially in #30 and #40...

Yep, I tried the short bits too.

Quote:

You can get a usable set from Harbor Freight; fine for drilling aluminum.

These rods are steel .. but I don't mind tearing a couple bits up if I can get them drilled properly.

Mark Dickens · #5 04-02-2018, 11:29 AM

I just take my hand drill and very carefully drill a #40 pilot hole on one side. Then put it in the jig and drill it through to the other side with the drill press. It's always worked for me.

rv7charlie · #6 04-02-2018, 11:50 AM

Quote:

Originally Posted by bkervaski

Yep, I tried the short bits too.

These rods are steel .. but I don't mind tearing a couple bits up if I can get them drilled properly.

I've used mine on steel quite a few times without noticeable issues. Don't expect them to last like hi-$ stuff, but you're not going to use something like this for production work.

wirejock · #7 04-02-2018, 12:04 PM

I center punch. Then use a tiny bit like #50 to drill a hole and move up incrementally. Tiny bit is less likely to wander from a punch mark. A V-block helps but not necessary.

Bavafa · #8 04-02-2018, 12:05 PM

Quote:

Originally Posted by Mark Dickens

I just take my hand drill and very carefully drill a #40 pilot hole on one side. Then put it in the jig and drill it through to the other side with the drill press. It's always worked for me.

Plus 1 for this method. All you need is a small pilot hole and light pressure on your drill press, throttle the arm of your drill press.

If this is the aileron push rod, the more challenging part is the riveting part. Go really slow with the rivet squeezer or better yet use your vice on the table (if you have one) to get the rivet set and then the rivet squeezer to finish it.

scard · #9 04-02-2018, 12:07 PM

Spot drill

RV7A Flyer · #10 04-02-2018, 12:10 PM

You could try this

http://www.aircraftspruce.com/catalo.../drillrite.php

although I seem to recall that the advice here, all taken together, was all I needed...short bit fully stuffed up into the arbor, start small, go VERY slowly, and make sure your workpiece is firmly clamped so it doesn't move. It's key to get the desired location dead nuts under the bit *and* at the very top of the tube...any off-to-the-side positioning will start the bit wandering.