Extreme grip size

[tnreefguy]

Is the Extreme grip a 14-4 I cant remember and my manual is not with me.

[Peter]

yep sure is.....

[Jerry]

Recently manufactured grips (18-20 months or so) have a 5mm bolt hole.

Jerry

[Peter]

True ,, I drilled mine to 5mm.......

[tnreefguy]

Thanks, I was away from my home and I wanted to order me a new set of Vs and I was unsure of the grip width.

[marked23]

I just bought some grips from HProz and they were 4mm.

-Mark

[DavidH]

Which part number did you order?

0317 Plastic grip with 4mm bolt hole
120-18 Main Blade Mount- M5 Blade Bolt

There is two plastic grips. 0317 is on the models up to 60 size. 120-18 with the 5mm bolt hole comes on the Extreme and Stratus.
They are the same other than the size of the bolt hole for the blade.

David

[marked23]

I ordered the 0317. My Extreme came with the 0317 so I didn't even know the 120-18 was an option. I don't have a problem with the 4mm, so I'm not likely to drill them out anyways.

-Mark

[DavidH]

I don't have a problem with the 4mm, so I'm not likely to drill them out anyways.


You start turning the head 1900 plus with 710-720 mm blades that weigh 185 grams plus. And I think you will see why the 5mm bolts are nessecary. I was bending the 4MM bolts regularly in F3C competion turning 1950 on the rotor headd with 195 gram blades. That was one of the reason MA went to 5MM bolts in the plastic grips.

David

[Knud Pedersen DENMARK]

My 4mm bolt are bend to - running SAB223 /1800rpm...... :shock: ...but is still flying with these slightly bend bolts :lol: :lol:

Is it okay just to drill up the 4mm hole to a 5 mm hole, in my plastic gripper??
:?:
ChopperKnud

[DavidH]

Knud,
The plastic grips I have I drilled out myself with a hand drill. I used numbered bits and just took a little material each time till I got to the size needed. I would suggest getting the 5mm bolts and measuring the diameter of the shank before drilling out the grips. The shank of 5mm is not quiet 5mm. You don't want the bolt loose in the grip, you want it to be like a press fit by hand. If I remember, the last bit I used to enlarge the hole in the grips was like 4.75mm. I swapped to 5mm bolts in the plastic grips before MA came out with the 5mm hole in the grips. I also use the same process to drill the holes in the blades. I use 3 different size bits and just take a little material with each one.

David

[marked23]

I run just 1750 headspeed. -Mark

[tnreefguy]

Thanks for the info David. I was thinking of trying a set of 710 mains. I didnt know of the issue with bending the grip bolts.

[Dr.Ben]

Something that needs to be understood RE the blade bolts bending-

There is no question that the 5mm bolt size eliminates this issue and represents the safest installation. What many guys are unaware of is that it is the flexing of the plastic grips under flight loads that bends the 4mm bolts and not simply the centripetal load of the blade. The bolts experience a shear kind of load as the grips flex up and down and this is apparent by the "s" shape that the bend takes on. The reason I know this to be a fact is that I've run 200 g blades at 1900+rpm for multiple season on MA heads with metal blade grips, and the 4mm bolts have NEVER bent. All of my heads have now being swapped out for 5mm inserts. I was, incidentally, bending 4mm bolts in plastic grips even with 680mm or smaller blades at as low as 1800 rpm. At the time, I immediately replaced the bolts when I saw them to be bent. After I realized that each set would bend in basically one flight, I stopped worrying about it until I had the option to swap hardware with the 5mm drag inserts.

Ben Minor