Screwing into aluminium.

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John Milford
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Screwing into aluminium.

Post by John Milford » Sun Feb 14 2021 20:19

I plan to fit vertical bars for drop arm alarms on the aluminium clamps of my boat rod holders.

I've got some 8mm aluminium bar and P clips to attach it with, but I was wondering if I need to tap a thread for a machine screw for the P clip, or whether the metal is soft enough to put a self-tapping screw staight into after just drilling a pilot hole?

Anyone tried it? :shrug:
"He's some sort of lure savant. Or just has an unhealthy addiction to old lures. We are not quite sure . . . . . "

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Andrew Croft
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Re: Screwing into aluminium.

Post by Andrew Croft » Sun Feb 14 2021 20:26

John Milford wrote:
I plan to fit vertical bars for drop arm alarms on the aluminium clamps of my boat rod holders.

I've got some 8mm aluminium bar and P clips to attach it with, but I was wondering if I need to tap a thread for a machine screw for the P clip, or whether the metal is soft enough to put a self-tapping screw staight into after just drilling a pilot hole?

Anyone tried it? :shrug:
Used to drill a lot of self tapers in to ali, thin sheets though and 4mm steel. 8mm might need a pilot hole eh. Used to break a s**t ton of the screws
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Re: Screwing into aluminium.

Post by John Milford » Sun Feb 14 2021 20:36

Andrew Croft wrote:
John Milford wrote:
I plan to fit vertical bars for drop arm alarms on the aluminium clamps of my boat rod holders.

I've got some 8mm aluminium bar and P clips to attach it with, but I was wondering if I need to tap a thread for a machine screw for the P clip, or whether the metal is soft enough to put a self-tapping screw staight into after just drilling a pilot hole?

Anyone tried it? :shrug:
Used to drill a lot of self tapers in to ali, thin sheets though and 4mm steel. 8mm might need a pilot hole eh. Used to break a s**t ton of the screws
The hole won't be 8mm Croftus, that's just the diameter of the bar and size of the P clip.

I figured if I drill a pilot hole just slightly smaller than the screw thread size, a steel screw would cut its own thread?

The danger of snapping off the screw was the thing I was most concerned about! :eek:
"He's some sort of lure savant. Or just has an unhealthy addiction to old lures. We are not quite sure . . . . . "

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Re: Screwing into aluminium.

Post by Andrew Croft » Sun Feb 14 2021 20:44

John Milford wrote:
Andrew Croft wrote:
John Milford wrote:
I plan to fit vertical bars for drop arm alarms on the aluminium clamps of my boat rod holders.

I've got some 8mm aluminium bar and P clips to attach it with, but I was wondering if I need to tap a thread for a machine screw for the P clip, or whether the metal is soft enough to put a self-tapping screw staight into after just drilling a pilot hole?

Anyone tried it? :shrug:
Used to drill a lot of self tapers in to ali, thin sheets though and 4mm steel. 8mm might need a pilot hole eh. Used to break a s**t ton of the screws
The hole won't be 8mm Croftus, that's just the diameter of the bar and size of the P clip.

I figured if I drill a pilot hole just slightly smaller than the screw thread size, a steel screw would cut its own thread?

The danger of snapping off the screw was the thing I was most concerned about! :eek:
Self tappers were a bloody nightmare. Made a nice bracket to hold my repurposed window wiper steering mechanism for my rc car last screw head comes clean of it 🤬 pulled the heed of it many times 🤪

Maybe try do the last turn by hand
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Re: Screwing into aluminium.

Post by Cyprio » Sun Feb 14 2021 20:47

8mm self tapper :laughs:

I would say you're be ok. Like you mentioned match the drill to the screw.
When I mounted my Scott'y bases to the Ali side of my boat I did tap a thread and fitted stainless bolts
my thoughts were it would make a stronger mount.
Depends how much metal you have to drill into. If it's not to wide use rivets :wink:
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Re: Screwing into aluminium.

Post by John Milford » Sun Feb 14 2021 21:29

Cyprio wrote:
8mm self tapper :laughs:

I would say you're be ok. Like you mentioned match the drill to the screw.
When I mounted my Scott'y bases to the Ali side of my boat I did tap a thread and fitted stainless bolts
my thoughts were it would make a stronger mount.
Depends how much metal you have to drill into. If it's not to wide use rivets :wink:
The clamp I'm drilling into is about 10mm thick Andy I think I'll risk it.

I plan to modify three rod holders. If it doesn't work on the first one, the worst that will happen is I'll have a snapped off screw to file flush and then re-think. :shrug:
"He's some sort of lure savant. Or just has an unhealthy addiction to old lures. We are not quite sure . . . . . "

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Re: Screwing into aluminium.

Post by Mike J » Mon Feb 15 2021 12:03

John Milford wrote:
Cyprio wrote:
8mm self tapper :laughs:

I would say you're be ok. Like you mentioned match the drill to the screw.
When I mounted my Scott'y bases to the Ali side of my boat I did tap a thread and fitted stainless bolts
my thoughts were it would make a stronger mount.
Depends how much metal you have to drill into. If it's not to wide use rivets :wink:
The clamp I'm drilling into is about 10mm thick Andy I think I'll risk it.

I plan to modify three rod holders. If it doesn't work on the first one, the worst that will happen is I'll have a snapped off screw to file flush and then re-think. :shrug:

Do it once a do it right.
Tap a thread or drill a clearance for bolt, lock washer and nut. :thumbs:

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'No Man Ever Fishes The Same River Twice, .... For It Is Not The Same River, .... And He Is Not The Same Man' Heraclitus of Ephesus

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Re: Screwing into aluminium.

Post by John Milford » Mon Feb 15 2021 13:15

The rod holders are a set of four I purchased recently - the superb old school 'Taylor Engineering' ones, de riguer for the lads fishing W**r W**d, back in the day. :cool:

That's why my other perfectly good boat rod holders went in the 'For Sale' section - to offset my extravagant purchase! (One set still available!. :wink: ).

My regular fishing pal is a garage door engineer. He might have a set of taps to do a pukka modification.

(In case anyone is wondering, the adaptation to fit back alarms is not necessarily for boat fishing. I also plan to use the holders on the front board of some particularly tight platforms I sometimes fish from).
"He's some sort of lure savant. Or just has an unhealthy addiction to old lures. We are not quite sure . . . . . "

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Re: Screwing into aluminium.

Post by spincityfan » Mon Feb 15 2021 13:32

Mike J wrote:
John Milford wrote:
Cyprio wrote:
8mm self tapper :laughs:

I would say you're be ok. Like you mentioned match the drill to the screw.
When I mounted my Scott'y bases to the Ali side of my boat I did tap a thread and fitted stainless bolts
my thoughts were it would make a stronger mount.
Depends how much metal you have to drill into. If it's not to wide use rivets :wink:
The clamp I'm drilling into is about 10mm thick Andy I think I'll risk it.

I plan to modify three rod holders. If it doesn't work on the first one, the worst that will happen is I'll have a snapped off screw to file flush and then re-think. :shrug:

Do it once a do it right.
Tap a thread or drill a clearance for bolt, lock washer and nut. :thumbs:

.
That's what I would do too.

Self tappers can be hit and miss going into anything other than thin sheet IMO

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Re: Screwing into aluminium.

Post by davelumb » Mon Feb 15 2021 13:35

Can you not effect a 'no screws' solution using Jubilee Clips or something? Or would that offend your tackle tart's sensibilities? :giggle:

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Re: Screwing into aluminium.

Post by John Milford » Mon Feb 15 2021 13:47

davelumb wrote:
Can you not effect a 'no screws' solution using Jubilee Clips or something? Or would that offend your tackle tart's sensibilities? :giggle:
I'm having palpitations at the very thought . . . ! :afraid:
"He's some sort of lure savant. Or just has an unhealthy addiction to old lures. We are not quite sure . . . . . "

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Re: Screwing into aluminium.

Post by davelumb » Mon Feb 15 2021 13:48

John Milford wrote:
davelumb wrote:
Can you not effect a 'no screws' solution using Jubilee Clips or something? Or would that offend your tackle tart's sensibilities? :giggle:
I'm having palpitations at the very thought . . . ! :afraid:
You don't fancy the gaffer tape solution? :joker:

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Re: Screwing into aluminium.

Post by andrew_nagel » Tue Feb 16 2021 01:08

Maybe these are something to consider John. These are A2 M5 stainless (come in a range of sizes) and are used in welding when you need to fasten on a threaded component. The lugs are tacked in place and the threaded tubular section can either sit proud or be recessed through a drilled hole. I've used them a lot in my boats as a 'flush nut'. For example when fastening things to the helm with bolts, if a standard washer and nut was used I'd end up with nuts standing proud on the cabin ceiling to cut my head on! I just cut the bolts to length drill and insert one of these from the underside of the helm and bolt into it from above. It makes a flush fastening - very neat.
I've also used them from one side only by drilling a hole in the material to match the outer dia of the tubular section. Then epoxied them in place. When set I can bolt into them. Just a thought...
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Re: Screwing into aluminium.

Post by Bucks Andy » Wed Feb 17 2021 09:53

John Milford wrote:
I plan to fit vertical bars for drop arm alarms on the aluminium clamps of my boat rod holders.

I've got some 8mm aluminium bar and P clips to attach it with, but I was wondering if I need to tap a thread for a machine screw for the P clip, or whether the metal is soft enough to put a self-tapping screw staight into after just drilling a pilot hole?

Anyone tried it? :shrug:
John. What size thread are you looking to tap. I have a box full of taps and can send whatever you need.

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