engine mount holes

If you have to redrill engine mount holes, what can be used to refill the holes. Or do you have to rip out the wood and start over?
Reason is one of the holes is off.
I need a drill press.
Thanks
Paul

Epoxy a hardwood dowel in the offending hole. Let it cure and tomorrow drill again.

A very handy gadget for spotting the holes is made by great planes.

A "Dead Center Engine Mount Hole Indicator"

http://www.greatplanes.com/accys/gpmr8130.html

>Epoxy a hardwood dowel in the offending hole. Let it cure
>and tomorrow drill again.
>
>A very handy gadget for spotting the holes is made by great
>planes.
>
>A "Dead Center Engine Mount Hole Indicator"
>
>
>http://www.greatplanes.com/accys/gpmr8130.html

You can also spot the holes with the oil ana talc method:

spread over the ounts a thin film of oil, can be machine oil, castor, or even cooking oil.

Put the engine in place, and fill the screw holes with talc.

When you remove the engine the place to drill them is very visble.

I've used JB Weld to fill old engine mount holes. The regular stuff (not the JB Kwik) seems to work best. If I can put a piece of tape on the bottom of the hole then fill it (actually overfill it) when I hit it with a heat gun it will flow in very nicely.

I let it set up for about a day then I can drill a new hole as close to the old one as needed.

You really need a drill press. Before I had one, I use a wiring drill bit to make the holes. Its a bit with a very long shaft, about 12". This allow me to drill a straight pilot hole while the engine is in place.

The hardest part of using a drill press is holding the airplane in place.

OF COURSE I'm just kidding!

Thanks guys!
I am not sure where to find "hard wood dowels" so I the JB weld is looking good. I will stop by H.D. this afternoon and see if they have the non-Kwik flavor. I don't have a heat gun but the wife has a MAJOR hair dryer. How much heat will it take?
Thanks
Paul

Your local hardware store, lumber yard, craft store, should have hardwood dowels in various sizes. I think the JB Weld will do the job just fine. I have a drill mounted on a stand type cheapie drill press which works ok. I took a small piece of motor mount and drilled some holes in it of various sizes and use that to get perpendicular holes on things I can't get into the 'drillpress'. I remember when I was poorer and had no drill. I would heat nails on the stove to burn holes in the motor mounts. Good old days?

Another hint is to not drill all 4 holes at once. I drill the first one, then tighten the engine down, and check to see if it is still pointing forward, , then mark the other 3. Take off the engine, and drill the next, bolt down and check to see if the marks still line up, etc. etc.

Sometimes it is hard to use the drill press, especially if the mounts are already in the plane. And as someone mentioned, a transfer punch to mark the holes, and keep the drill in the right location is a good idea too.

If you get a really tight fit with your dowels (I taper them ever so slightly, when filling in holes, and pound 'em in), you can weep in thin CA to hold them in place. Instead of epoxy, which works, but if the fit is too tight, it sometimes get scrubbed off.

LAST EDITED ON Jan-26-04 AT 10:56 PM (CDT)
 
A free source of small dowels that will fill the hole is those round toothpicks for free at the cash register at Cracker Barrel junk store and restaurants. It works for me. I always take ten or more each time. Don't buy the package of them, just take the free ones.

Another reason many holes wind up out of place is that drill bits made for metal tend to wander in wood. Try "pilot point" drill bits by dewalt (I think) or brad point bits. They will yield much better results if you have to fill a hole and redrill half of it. In this case, filling the hole with wood works the best. If it's more than a diameter away, about anything will work, at least has for me.

Tools

A center punch, awl or icepick can be a handy device to have when you only have the older plane jane drill bits. Put some kind of indentation there and your bit wont skip.

LAST EDITED ON Jan-27-04 AT 03:01 PM (CDT)
 
Great idea Mike and so obvious I over looked it for years. Too many years boring holes in metal. So this afternoon I went to the new Home Depot and got a set of drill bits with pilots. Uuhrah.

After looking it over I did not like the other 3 holes so I filled them all back in with JB weld. (Man the heat gun tricked work well!!)

My question is can I move the engine just in front of the old holes? Or does the enging have to sit all the way back in the slot?

Thanks
Paul

PS - I got a small drill press to mount my hand drill in.

Yes, you can move the engine forward. Main things to consider are spinner fit (if it's an issue at all), and balance. If it's not really nose heavy to begin with, shouldn't be a huge problem.

You might also want to consider making little engine plates to go between the engine and the mounts (if the height of the plates isn't a problem). Just like are used on profiles, but without the taper.

Tools

Good News.. Thanks Mike
BTW this is a profile plane. And I have no spinner.

>Try "pilot
>point" drill bits by dewalt (I think)

That is what I use.

My method for marking engine holes was stolen from Winfred. Chuck a 1/8" copper tube in a hand drill. Hold the engine in place and place the tube in each hole and spin it. It will leave perfect circles.

Centerpunch the circles and drill.

Never thought of that, great idea!

Here's a method I'm curious if anyone here ever tried. Dad said when he was in Turkey in the service in the mid 60's, they "drilled" engine mount holes by heating a nail cherry red and shoving and twisting it through the hardwood. Would take several attempts for each hole, and not a trivial amount of time getting the nail hot enough using a zippo lighter or a kerosene heater! He didn't own a drill. From what I'm told, longevity wasn't really a concern!

Tools

Other then looks and the use of a starter is there another reason for a spinner?

Yes. They can sometimes save your crankshaft when you crash. When the spinner explodes it absorbs a lot of the force.

If you are drilling your mounting holes while the engine is in place. Always remember to tape off the exhaust port surface so the side of the drill doesn't rub against it and damage it.