Correcting a Toe In rear drill

oobigfish
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Posts: 336

Correcting a Toe In rear drill Apr 10, 2020 16:01:42 GMT -5 via Tapatalk

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Post by oobigfish on Apr 10, 2020 16:01:42 GMT -5

I’ve been noticing a consistent slight toe in issue on my rear drill using the clear jig.

When I test the jig, it seems flawless, no issues with taps side to side, but after I drill there’s always a slight toe in.

Is there something I can do to prevent this? The block is snug in the block and I am using snug bits in the jig. I use a pin gauge to keep the block in place after the first drill and use a clamp to hold the block and jig stationary.

I’ve tried it with a hand drill and pin vise and I clear the wood as I drill.

I’d fill and redrill, but I’m not confident the drill would be any better on the second attempt.

Any suggestions on figuring out which side of the drill is off?

Ember
Overlord

If you play with fire, you might get burned.

Posts: 1,499

Correcting a Toe In rear drill Apr 10, 2020 16:17:26 GMT -5 Cherokee Chuck and oobigfish like this

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Post by Ember on Apr 10, 2020 16:17:26 GMT -5

There is always some amount of play in the bushings, my GB jig is the same way. After you learn your jig, you may need to slightly bias the drill one way or another while drilling. I've screwed up far more bodies with a pin vise than I have using a battery drill.

You can straighten a slight toe issue with a reamer. Once you know which way to bias the reamer you can straighten the hole a small amount.

If the body is straight and square you can use 123 blocks, a machinist square, or even a piece of graph paper to see which side(s) are giving you trouble.

Never trust an atom, they make up everything !

Professor Moriarty
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Correcting a Toe In rear drill Apr 10, 2020 18:11:01 GMT -5 oobigfish likes this

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Post by Professor Moriarty on Apr 10, 2020 18:11:01 GMT -5

It could be a result of your test... There are many ways to go wrong with the test that will skew the results.

Another possibility is...

The height of your front drill in relation to your rear drill...

I always mark the side of the body where I want to drill the front hole... then I will shim up or flip the body over or do whatever is needed to hit that mark.

It’s about to kick off...

oobigfish
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Posts: 336

Correcting a Toe In rear drill Apr 10, 2020 19:18:29 GMT -5 via Tapatalk

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Post by oobigfish on Apr 10, 2020 19:18:29 GMT -5

I did some more checks with a 123 block, and rear of the back axle is not 100% square. It seems like forward of the axle the block is square.

I used a cut down BSA block. Going to have to order some better blanks before I start another build.

Ember
Overlord

If you play with fire, you might get burned.

Posts: 1,499

Correcting a Toe In rear drill Apr 10, 2020 19:35:15 GMT -5 Professor Moriarty likes this

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Post by Ember on Apr 10, 2020 19:35:15 GMT -5

As long as the block was tight in the jig and didn't move, the two rear drills should be perfectly in-line with each other, even if that line is not square to the block. Think of a solid straight axle going across the back of the car, something like this top view l--l If the axles are inline, but not square to body, something like this /--/ If both rears were severely toed in, something like this ...l V l.

Last Edit: Apr 10, 2020 22:18:56 GMT -5 by Ember

Never trust an atom, they make up everything !