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Old June 12, 2019, 23:27   #1
Orion the Hunter
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Hole Size vs. Pin Size

Greetings!

I have a FN Para Knuckle that has a 13/64ths hole in it (where the old Pin use to go). I plan on installing a new Para-Stock Assembly which requires me to take a 13/64ths Drill Bit and (using the previous holes in the Knuckle as a Pilot) Drill through the arms of the Para-Stock so they can be pinned in place.

The Question: What is the correct size of “Spring Pin” to use for that size hole (13/64ths)?

Thanks!
Orion the Hunter
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Old June 13, 2019, 05:37   #2
yovinny
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No machinist handbook ??
Google 'spring pin fitment chart',,,it will give you sizes and recommended hole range.
You may well be dealing with a metric size, as 13/64 rings no bells for me.
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Old June 13, 2019, 06:16   #3
Grahamneall
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Oh no.....another roll pin thread !!
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Old June 13, 2019, 08:06   #4
gunplumber
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Drill 5mm hole.
Instal 5mm roll pin (or coil pin)

Unlike interference fit solid pins, the roll pins are already (over) sized for the hole. That's the point of them.
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Old June 13, 2019, 11:17   #5
mountainman
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Quote:
Originally Posted by Orion the Hunter View Post
Greetings!

I have a FN Para Knuckle that has a 13/64ths hole in it (where the old Pin use to go). I plan on installing a new Para-Stock Assembly which requires me to take a 13/64ths Drill Bit and (using the previous holes in the Knuckle as a Pilot) Drill through the arms of the Para-Stock so they can be pinned in place.

The Question: What is the correct size of “Spring Pin” to use for that size hole (13/64ths)?

Thanks!
Orion the Hunter
Measure the pin at various points. Take the biggest diam you obtained and subtract about .009" from that. That is the drill size you need ( drilled holes always end up around .003" bigger than the drill unless reaming and other tight procedures are used). Use a drill chart to find the closest drill to that. Don't forget to give the hole a slight countersink after done drilling.
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Old June 15, 2019, 19:52   #6
lysanderxiii
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Quote:
Originally Posted by gunplumber View Post
Drill 5mm hole.
Instal 5mm roll pin (or coil pin)

Unlike interference fit solid pins, the roll pins are already (over) sized for the hole. That's the point of them.
^^This.^^

A 13/64 hole is 5.16 mm in diameter. The actual diameter of a 5mm slotted spring pin is 5.4mm to 5.6mm and are designed to fit in holes 5.00mm to 5.12mm.

EDIT: There are no US Standard spring pin that fit 13/64", you get 3/16" (.187" to .192" holes) 7/32" (.219" to .224") holes.

Last edited by lysanderxiii; June 15, 2019 at 19:58.
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