Drilling a straight 20mm hole through 250mm oak gate post.

[PearlyKing]

I am replacing a rotted gate gate post. It is 250mm square and 2100mm high,above ground, 2800mm overall,. I am trying to work out how to drill the hinge bolt holes keeping them straight and parallel to the ground.

I don't want to drill them before I install the post as I don't believe that I can position it accurately enough to be level with the other gate post hinges.

One thought was to screw on a pipe holding base/wall flange as per attached photos, with the grub screw removed; it is 30mm deep, which I am hoping is enough to keep the drill bit straight. Any criticism or other thoughts and suggestions very welcome.

 

[RichardG]

A few suggestions.

Find a spot on your drill where you can attach a tiny bubble level so it’s level when the drill is horizontal, that will sort out one axis.

Drill the same size hole through a piece of >100mm timber using your pillar drill. Use this as a guide to start the drilling. Once you’re in as far as you can you should be ok to remove it and then complete the hole.

You could add a drill guide to your tools, e.g. Drill Guide

 

[Sheffield Tony]

How accurate is needed ? I'd go for a Scotch eye auger, and an assistant standing back to judge level. But you might prefer a 21st century method ...

 

[PearlyKing]

A few suggestions.

Find a spot on your drill where you can attach a tiny bubble level so it’s level when the drill is horizontal, that will sort out one axis.

Drill the same size hole through a piece of >100mm timber using your pillar drill. Use this as a guide to start the drilling. Once you’re in as far as you can you should be ok to remove it and then complete the hole.

You could add a drill guide to your tools, e.g. Drill Guide

Thanks. I really like the second idea.

 

[PearlyKing]

How accurate is needed ? I'd go for a Scotch eye auger, and an assistant standing back to judge level. But you might prefer a 21st century method ...

Pretty accurate so that the two driveway gates will line up. I had to Google "Scotch eye auger", never seen one before but that does look a lot easier to control than a power drill. Thanks

 

[Doug71]

Can you just level a line around the post and drill in from both sides, I'm sure you won't be that far out and will be able to make the holes line up with a bit of jiggling?

 

[PearlyKing]

Can you just level a line around the post and drill in from both sides, I'm sure you won't be that far out and will be able to make the holes line up with a bit of jiggling?

That sounds doable. Thanks.

 

[novocaine]

Washer trick.
Put a washer over the shank of the drill, if you are level as you drill it will stay still. Angled up it will slide backward, angled down it will slide forwards.

Only video i can find.

 

[AdamM]

I am replacing a rotted gate gate post. It is 250mm square and 2100mm high,above ground, 2800mm overall,. I am trying to work out how to drill the hinge bolt holes keeping them straight and parallel to the ground.

I don't want to drill them before I install the post as I don't believe that I can position it accurately enough to be level with the other gate post hinges.

One thought was to screw on a pipe holding base/wall flange as per attached photos, with the grub screw removed; it is 30mm deep, which I am hoping is enough to keep the drill bit straight. Any criticism or other thoughts and suggestions very welcome.

I drilled a gate post last week. This seemed to work OK (1) I used my pillar drill tthrough a piece of was 2x4 as a guide (2) clamped this to the hinge side
of the gate-post as a guide (v impt) (3) started drilling (4) removed the bit of 2x4 and completed the hole. Seemed work OK.

 

[pe2dave]

Washer trick.
Put a washer over the shank of the drill, if you are level as you drill it will stay still. Angled up it will slide backward, angled down it will slide forwards.
Only video i can find.

What a brilliant (simple) idea! Physics is a wonderful thing!

 

[Jackbequick]

I am replacing a rotted gate gate post. It is 250mm square and 2100mm high,above ground, 2800mm overall,. I am trying to work out how to drill the hinge bolt holes keeping them straight and parallel to the ground.

I don't want to drill them before I install the post as I don't believe that I can position it accurately enough to be level with the other gate post hinges.

One thought was to screw on a pipe holding base/wall flange as per attached photos, with the grub screw removed; it is 30mm deep, which I am hoping is enough to keep the drill bit straight. Any criticism or other thoughts and suggestions very welcome.View attachment 93630

You can readily (after drilling the holes, adjust post height before fixing it into the ground, in alignment with the other post....That's a common way of doing the job however if averse to it as it seems and some good suggestions have come through for use one or all together..!!...

250mm isn't much and if you use an auger (in good nick) it will draw itself through.

It's all in the preparation... Your post might not end up exactly vertical anyway in the way you are doing things. By the way, and not knowing your bolt size.,. you could use coach bolts (tapered, hex headed galvanised with suitable washer ) and end up only having to drill 3 inches if that makes it easier.

If you are at the correct and comfortable working height and doing it your way you should have no problem keeping the holes straight. DO NOT drill above your head, drilling should be done at elbow level...not chest chin or eyes or higher...

Another method If the other post is reasonably close...say 6-8 feet away, fix your post securely in the ground. Bear in mind that cement will trap water in the timber and help it rot,. If just if using soil...when filling arond the post...and keep the level on it...stamp it down hard every few inches of fill......Don't fill the hole around the post THEN stamp it with the knob on a spud bar , that will let the post loosen up...Nail a batten horizontally between the posts with the batten edge just below the existing hole, then do the same again on the opposite side...Now you can confidently drill using them as guides. Fix the hinge with one bolt, mark the other holes remove the hinge and drill keeping wits about you...don't'wander off'

Use an auger for 250 mm not a speed-bore or HSS but for the short distance if using coach bolts sharp HSS correct for the coach bolt, will be ok.

 

[PearlyKing]

You can readily (after drilling the holes, adjust post height before fixing it into the ground, in alignment with the other post....That's a common way of doing the job however if averse to it as it seems and some good suggestions have come through for use one or all together..!!...

250mm isn't much and if you use an auger (in good nick) it will draw itself through.

It's all in the preparation... Your post might not end up exactly vertical anyway in the way you are doing things. By the way, and not knowing your bolt size.,. you could use coach bolts (tapered, hex headed galvanised with suitable washer ) and end up only having to drill 3 inches if that makes it easier.

If you are at the correct and comfortable working height and doing it your way you should have no problem keeping the holes straight. DO NOT drill above your head, drilling should be done at elbow level...not chest chin or eyes or higher...

Another method If the other post is reasonably close...say 6-8 feet away, fix your post securely in the ground. Bear in mind that cement will trap water in the timber and help it rot,. If just if using soil...when filling arond the post...and keep the level on it...stamp it down hard every few inches of fill......Don't fill the hole around the post THEN stamp it with the knob on a spud bar , that will let the post loosen up...Nail a batten horizontally between the posts with the batten edge just below the existing hole, then do the same again on the opposite side...Now you can confidently drill using them as guides. Fix the hinge with one bolt, mark the other holes remove the hinge and drill keeping wits about you...don't'wander off'

Use an auger for 250 mm not a speed-bore or HSS but for the short distance if using coach bolts sharp HSS correct for the coach bolt, will be ok.

Many thanks for the suggestions. I have to use the existing hinges as they were custom made for the shape of the gates. The lower hinge uses a spiked bolt, about 140mm (and I have bought a new one) but the upper hinge has a threaded bolt that goes all the way through the 250mm post. It is a pair of gates, 78 inches each. Once I have dug out the old post, I will see how comfortable I am manoeuvring the new one, it may well be that I feel quite confident with it and decide to drill it on the flat. I have a laser level so I should be able to line up the two hinges.
Thanks again.

 

[Jackbequick]

just a rounding...at that top hinge height these are not farm gates and could be steel aluminium of timber, so weight is uncertain. The coach bolt may do the job quite well...I've used them into timber strainers on 12 ft 6 farm gates.

Using bolts...If you don't want any break-in...sink the nut into the timber about 30mm..., cut the bolt about an inch (25mm) longer than needed to fill the nut then pin-punch or even put touch of weld on the end of the bolt thread. Having the end of the bolt level with the edge of the post will stop hack-sawing it off.

 

[Bm101]

A couple more suggestions... Get a waste bit of timber of similar size. Chuck it in a vise. Drill 19 holes in it as if it was the real thing. By the 20th you should be bang on. Drill your post right then not two days later.
When drilling I I check whatever vertex my head is not leaning over first. Thats normally 'up and down' to 90ish degrees. I concentrate on keeping that line. Left and right is easier to see as you drill because you don't have to move your head (and therefore your body).
If you can drill a few mill over on a bolted gate this will give you a little play.
If you have a mate with a pillar drill get them to drill you a template in a 3" bit of waste... Screw that to your post. Jobs a goodun.

 

[Jonm]

Some years ago I replaced the posts on a pair of sturdy solid timber gates, each one about 6ft by 5ft. Did a thorough job with strong concrete both under and around the posts. Posts did not move until about 15 years or so later when they rotted through. The posts in the ground were complete mush, the concrete was superb, perfectly watertight, I had created a waterproof pond for the posts to sit in. So I agree with jackbequick about concrete and posts rotting.

I would overdig the base of the hole and fill to the underside of the post with sharp sand and gravel to provide drainage and it will compact easily. If you decide to pre drill the holes you could set out the top level of the sand and gravel with your laser level. As for backfill around the sides of the post, I think I would still go for concrete or part fill with sand and gravel then top off with concrete. unless movement of the post is acceptable. A bag or two of postcrete initially around the post will set quickly and hold the post in place then you can top off with concrete.