 |
|
24 June 2017, 09:19
|
#1
|
|
Member
Country: USA
Town: Usa
Boat name: mgmak
Make: mgmakGD
Length: 3m +
Engine: mgmakGD
MMSI: 2192
Join Date: Oct 2016
Posts: 79
|
What size pilot holes when using screws on consoles?
Hi
Just fitted a new plotter and managed to chip off some of the gelcoat when tightening the screw. 
Now I think this was caused by being too near the edge and also the pilot hole was maybe too small as I needed quite a lot of force to turn the screw.
I went small on the pilot hole as I was paranoid that if it was too big, the screw would not grip and not cut into the GRP properly.
Can anyone suggest any guidance, e.g. 6mm screw - 4mm pilot hole?
The Lowrance installation manual didn't specify a size.
__________________
|
|
|
|
24 June 2017, 09:48
|
#2
|
|
Member
Country: UK - England
Town: South Yorks
Boat name: Black Pig
Make: Ribcraft
Length: 5m +
Engine: DF140a
MMSI: 235111389
Join Date: Feb 2008
Posts: 12,178
|
What size pilot holes when using screws on consoles?
Ooh a hole drilling thread, I've haven't done one of these yet[emoji6] GRP is very unforgiving, for a 6mm screw I'd go 4.5-5mm pilot. Also counter sink the pilot hole just to clear the gel coat, this will stop it from spalling off.
__________________
Rule#2: Never argue with an idiot. He'll drag you down to his level & then beat you with experience.
Rule#3: Tha' can't educate pork.
Rule#4: Don't feed the troll
|
|
|
|
|
25 June 2017, 06:58
|
#3
|
|
Member
Country: USA
Town: Mercer Island, WA
Make: Rendova 12 & 16
Length: 5m +
Engine: 40 & 90
Join Date: May 2017
Posts: 11
|
Quote:
Originally Posted by Gobuchul
I went small on the pilot hole as I was paranoid that if it was too big, the screw would not grip and not cut into the GRP properly.
Can anyone suggest any guidance, e.g. 6mm screw - 4mm pilot hole?
|
I don't trust screws in GRP. In fact just today I replaced 4 of them with #10 t-nuts that I epoxied in so I can use real fasteners.
__________________
|
|
|
|
|
25 June 2017, 22:01
|
#4
|
|
Member
Country: UK - England
Town: southampton
Boat name: TOP CAT 2
Make: Scorpion 8.1
Length: 8m +
Engine: 250hp HO
Join Date: Aug 2003
Posts: 1,827
|
Seems to be a very tricky compromise between to small a hole that snaps screw or rounds it off to a hole to big that doesn't bite
By eye I make sure drill bit is no bigger than the non threaded element of the screw. If that makes sense. I don't know if it's correct but seems to work for me
__________________
|
|
|
|
|
25 June 2017, 23:02
|
#5
|
|
Member
Country: UK - Scotland
Town: north ayrshire
Boat name: charlie girl
Make: S/R5.4/regal3760
Length: 10m +
Engine: Suzukidf70 2x6lp 315
Join Date: Jul 2009
Posts: 4,027
|
Stainless screws snap like carrots best to use a steel screw to cut the thread then replace with stainless the same size
__________________
|
|
|
|
|
26 June 2017, 08:16
|
#6
|
|
Member
Country: UK - England
Town: Retford
Boat name: Spy-sea-one
Make: Excel 435
Length: 4m +
Engine: Suzuki Outboard/25/4
Join Date: Oct 2011
Posts: 7,532
|
use self drilling screws and tape over the screw hole before drilling i find works well
__________________
|
|
|
|
|
26 June 2017, 09:09
|
#7
|
|
Member
Country: UK - England
Town: Wild West
Boat name: No Boat
Make: No Boat
Length: under 3m
Join Date: Jan 2008
Posts: 5,306
|
Simple...
Unless it's absolutely unavoidable (ie retro fitting or access issues)...Don't use Screws..whatever flavour!..AT ALL! 
On My Rib Craft build I used 100% Domed "Allen Key" Stainless "Nylock" Nut and bolts with washers...which are available in ALL sizes..
IMO makes for a Far superior job,ALOT stronger,better torsion control ,much less chance of cracking Gel Coat,easier to remove,..looks so much better/neater too 
Just pick a the size bit (a slightly worn one is better as it won't snag in the gel coat) to suit the Bolt!
__________________
A clever Man learns by his mistakes..
A Wise Man learns by other people's!
The Road to HELL ..is Paved with "Good inventions!"
|
|
|
|
|
26 June 2017, 15:23
|
#8
|
|
Member
Country: USA
Town: Mercer Island, WA
Make: Rendova 12 & 16
Length: 5m +
Engine: 40 & 90
Join Date: May 2017
Posts: 11
|
Another option might be to mount a piece of teak, perhaps even using 5200, and screw to that. Through-bolting is preferred all around but sometimes the back is inaccessible, though a strategic deck plate can assist.
__________________
|
|
|
|
|
26 June 2017, 19:04
|
#9
|
|
Member
Country: UK - England
Town: Wild West
Boat name: No Boat
Make: No Boat
Length: under 3m
Join Date: Jan 2008
Posts: 5,306
|
Quote:
Originally Posted by Pikey Dave
Ooh a hole drilling thread, I've haven't done one of these yet[emoji6] GRP is very unforgiving, for a 6mm screw I'd go 4.5-5mm pilot. Also counter sink the pilot hole just to clear the gel coat, this will stop it from spalling off.
|
Just how many "Self Tappers " Did you use Black Pig Dave!?? 
...Not many I bet! 
__________________
A clever Man learns by his mistakes..
A Wise Man learns by other people's!
The Road to HELL ..is Paved with "Good inventions!"
|
|
|
|
|
26 June 2017, 23:15
|
#10
|
|
Member
Country: UK - England
Town: South Yorks
Boat name: Black Pig
Make: Ribcraft
Length: 5m +
Engine: DF140a
MMSI: 235111389
Join Date: Feb 2008
Posts: 12,178
|
Quote:
Originally Posted by Maximus
Just how many "Self Tappers " Did you use Black Pig Dave!??
...Not many I bet!
|
Aye not many, I would've had to buy em[emoji6]
__________________
Rule#2: Never argue with an idiot. He'll drag you down to his level & then beat you with experience.
Rule#3: Tha' can't educate pork.
Rule#4: Don't feed the troll
|
|
|
|
|
27 June 2017, 09:30
|
#11
|
|
Member
Country: UK - England
Town: Wild West
Boat name: No Boat
Make: No Boat
Length: under 3m
Join Date: Jan 2008
Posts: 5,306
|
Quote:
Originally Posted by Pikey Dave
Aye not many, I would've had to buy em[emoji6]
|
Atta Boy!
__________________
A clever Man learns by his mistakes..
A Wise Man learns by other people's!
The Road to HELL ..is Paved with "Good inventions!"
|
|
|
|
|
27 June 2017, 19:38
|
#12
|
|
Member
Country: UK - Scotland
Town: Fort William
Make: Ribcraft 585
Length: 5m +
Engine: Yamaha F115
Join Date: Mar 2012
Posts: 2,919
|
Quote:
Originally Posted by Pikey Dave
Aye not many, I would've had to buy em[emoji6]
|
Get away!
Don't tell me there aren't several boxes of s/s screws in that shed...
__________________
There is a place on this planet for all of Gods creatures.........right next to my tatties and gravy.
|
|
|
|
|
27 June 2017, 19:56
|
#13
|
|
Member
Country: UK - England
Town: South Yorks
Boat name: Black Pig
Make: Ribcraft
Length: 5m +
Engine: DF140a
MMSI: 235111389
Join Date: Feb 2008
Posts: 12,178
|
Quote:
Originally Posted by A1an
Get away!
Don't tell me there aren't several boxes of s/s screws in that shed...
|
Might be[emoji6]
__________________
Rule#2: Never argue with an idiot. He'll drag you down to his level & then beat you with experience.
Rule#3: Tha' can't educate pork.
Rule#4: Don't feed the troll
|
|
|
|
|
27 June 2017, 20:12
|
#14
|
|
Member
Join Date: Jun 2010
Posts: 2,934
|
ach...just rattle them right in
__________________
|
|
|
|
|
27 June 2017, 21:53
|
#15
|
|
Member
Country: UK - England
Town: Lincoln
Boat name: Zoom
Make: Zodiac
Length: 3m +
Engine: Mariner 10
Join Date: Sep 2016
Posts: 80
|
Is that how they fitted your new seats [emoji6]
__________________
|
|
|
|
|
28 June 2017, 09:43
|
#16
|
|
Member
Country: UK - England
Town: Wild West
Boat name: No Boat
Make: No Boat
Length: under 3m
Join Date: Jan 2008
Posts: 5,306
|
Quote:
Originally Posted by Xk59D
ach...just rattle them right in |
At least HE missed the Trailer Bunks!
__________________
A clever Man learns by his mistakes..
A Wise Man learns by other people's!
The Road to HELL ..is Paved with "Good inventions!"
|
|
|
|
|
28 June 2017, 10:03
|
#17
|
|
Member
Country: UK - Scotland
Town: Girvan & Tayvallich
Boat name: Breawatch
Make: Ribcraft
Length: 5m +
Engine: Mercury 150 F/stroke
MMSI: ex directory!!
Join Date: Sep 2008
Posts: 6,203
|
Quote:
Originally Posted by Xk59D
ach...just rattle them right in |
Ok Paul spill the beans what was the event that resulted in that horrendous botched job?
__________________
jambo
'Carpe Diem'
Member of the ebay Blue RIB cover club
Member of SABS ( Scottish West Division)
|
|
|
|
|
28 June 2017, 10:15
|
#18
|
|
Member
Join Date: Jun 2010
Posts: 2,934
|
I seen it ages ago on another forum. Btw the owner done that to both sides of the boat so it would at least sink squarely.
__________________
|
|
|
|
|
28 June 2017, 10:31
|
#19
|
|
Member
Country: UK - England
Town: Retford
Boat name: Spy-sea-one
Make: Excel 435
Length: 4m +
Engine: Suzuki Outboard/25/4
Join Date: Oct 2011
Posts: 7,532
|
Quote:
Originally Posted by Xk59D
ach...just rattle them right in |
i looked at this a few times thought it was a pi55 take the screws look massive more like coach bolts they stick in telegraph poles
__________________
|
|
|
|
|
29 June 2017, 19:38
|
#20
|
|
Member
Country: UK - England
Town: Leicester
Length: 5m +
Engine: 135hp Mercury
Join Date: Sep 2013
Posts: 1,431
|
At least it should keep the barnacles at bay....
__________________
|
|
|
|
|
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
BLACK PIG
Piglet
spy-sea-one
Red Mist
Breawatch
