Grip length

[fly_tornado]

I am bolting 2 bits of alloy bar and angle together, the bar is 3/8" thick and the angle is 1/4" thick.

 

This is a total thickness of 10/16" but I can only get -9 or -11, no problem as I need to use a washer.

 

Is that correct? An AN960-516 washer is 1/16" thick?

 

 

[pudestcon]

I am bolting 2 bits of alloy bar and angle together, the bar is 3/8" thick and the angle is 1/4" thick.This is a total thickness of 10/16" but I can only get -9 or -11, no problem as I need to use a washer.

 

Is that correct? An AN960-516 washer is 1/16" thick?

I'm not sure what you are asking exactly ft, but don't forget the nut!!

Pud

 

 

[fly_tornado]

sorry, Ill try and make my question a bit more clearer the an5-10 bolt has a 9/16" grip length and the an5-11 has a 11/16" grip length. How much shorter should the grip length of a bolt be under the thickness of the material you are joining, in this case 10/16"+ washer thickness?

 

Does the bolt stretch much?

 

 

[facthunter]

Less than 1/2 millimetre I would think. You don't want it to bottom on the thread before you achieve your tension.. . I would try for the thread to be below the surface of the top piece of alloy. by this amount. Tighten it without a washer and observe whether it binds, then add the washer. then you have the washer to give you the extra allowance that you need. Half a mm. is 20 thou. ( almost). The less thread in the Al pieces the better. Presume it has some sheer load. Nev

 

 

[Ultralights]

you want minimum 1 thread and max 4 thread showing after the nut is fitted. you can use max 2 washers of any thickness on any one side of the fastener. (general aircraft structural engineering principles)

 

 

[old man emu]

I am bolting 2 bits of alloy bar and angle together, the bar is 3/8" thick and the angle is 1/4" thick.This is a total thickness of 10/16" but I can only get -9 or -11, no problem as I need to use a washer.

 

Is that correct? An AN960-516 washer is 1/16" thick?

POINT 1:

 

AN bolt sizes are given in increments of 1/8". They refer to the overall length of the bolt from underneath the head to the far end of the thread. Therefore for a bolt with an overall length of less than 1", the figures used are between -3 and -7 (called Dash3 and Dash7). Once the bolt has reached 1", the length is given as -10. In other words, 1 inch and no eights. After 1" you use the numbers -11 to -17. Then you are at 2" so you go from -17 to -20.

 

There is no such thing as a Dash 9. It is a Dash 11 (9/8 = 1" + 1/8)

 

POINT 2:

 

The thickness of the material you want to bolt together is 5/8" (0.625"). In general, you can only have the unthreaded part of the bolt in the material that is being bolted together. So that means that your Grip Length has to be greater than the length of the hole through the material. But you have to be able to get the bolt torqued down on the surfaces to get the materials properly fastened together. You cannot use more than two washers.

 

The closest Grip Length that would do the job in an AN5 bolt is an AN5-11, which has a Grip Length of 0.688".

 

POINT 3:

 

Describing washers as AN960 is soooo last week. They are now known as NAS1149F-(size).

 

There are three possible thicknesses you can use:

 

0516, which is 0.016" thick

 

0532, which is 0.032" thick, and

 

0563, which is 0.063" thick.

 

Now, the thickness of the washer you will need is: Grip Length - Material Thickness = 0.688 - 0.625 = 0.063.

 

Therefore you need an NAS1149F0563 washer.

 

POINT 4:

 

The overall length of the AN5-11 bolt is 1.219", which leaves 0.531" of thread for the nut to run down on. You did not specify where these pieces are going, but if you are going to bolt them together, I imagine that you don't want any movement in the joint. Therefore you could use an AN315-5 nut, or an MS21044N5 nyloc nut.

 

This nut and bolt combination should be torqued to 100 - 140 lb-in.

 

Old Man Emu

 

 

[fly_tornado]

building a variation on this

 

http://www.titanaircraft.com/manuals/tornado_instruction_manual/96-INS-0796-B.pdf

 

 

[old man emu]

Thanks for posting the plan. It helps.

 

I was going to mention another designation for bolts. This is the NAS system, which is a later system than the 1940's AN system.

 

The main difference between the two systems in sizing is that AN increases sizes by 1/8", and the size describes the overall length of the bolt. You have to work out the Grip Length by referring to a Table of Grip Lengths. This is OK if you have access to the book, like I do.

 

NAS sizing describes the Grip Length in increments of 1/16". There are two families of NAS bolts : NAS62xx and NAS66xx. The 62's have shorter thread lengths than the 66's, otherwise the two families are the same.

 

To fasten material 5/8" thick you could use an NAS6205-10, or an NAS6605-10 bolt.

 

After looking at the plan you supplied, I was wondering how hot it will get around that mount. You have to remember that the MS21044N5 nyloc nut only has the ability to with stand a maximum temperature of 250F. If it is going to get hotter than that, you could use an MS21045N5 which can take up to 450F.

 

OME

 

 

[fly_tornado]

I have been relying on http://www.aircraftspruce.com/catalog/hapages/an5.php

 

 

[old man emu]

I find it a lot that people are not aware of all the hardware that is available. I suppose when hardware is your business you should know a bit about it.

 

OME

 

 

[fly_tornado]

Theres masses of nuts and bolts. Imperial really sucks if you have been raised with metric.

 

So what is the difference between the AN364 and AN365 nuts?

 

http://www.aircraftspruce.com/catalog/hapages/an363_1.php

 

 

[Yenn]

AN365 is a standard elastic stop nut,

 

AN364 is a shear elastic stop nut, designed to work as a stop nut but is shorter than 365 and not designed for tension loads

 

AN363 is a metal stop nut, for higher temperatures

 

AN310 is a standard castle nut

 

AN320 is a shear castle nut

 

Get yourself a Wicks or Aicraft Spruce catalogue and just about anything you need will be described.

 

 

[old man emu]

Some of the part numbers given above are out of date

 

AN365 is now MS21044N(XX)

 

AN364 is now MS21083N (XX)

 

AN363 is now MS21045- (XX)

 

I have a reference book that I use daily to identify and order hardware. I also have it as a pdf file on CD-ROM. If anyone is interested in obtaining a copy, I am happy to send a CD-ROM for the cost of postage and packaging only. That's about $2.50. Just contact me via the Conversations facility of this forum.

 

Old Man Emu

 

 

[fly_tornado]

someone might fnd this torque guide handy

 

TORQUE VALUES FOR AIRCRAFT BOLTS.pdf

 

TORQUE VALUES FOR AIRCRAFT BOLTS.pdf

 

TORQUE VALUES FOR AIRCRAFT BOLTS.pdf

[spacesailor]

I agree "fly-tornado" Metric sucks when speaking english rather than french!

 

Bryan

 

 

[spacesailor]

I,m getting material from USA but the postal cost are out of hand now

 

(eg: pito tube $16 + post $ 40 from Spruce ).

 

So working in Imperial, US & Aussie is easier for this want to be eagle.

 

bryan

 

 

[fly_tornado]

and just to add that bit of extra complexity I find this article today!

 

http://www.sportaviationonline.org/sportaviation/201202#pg98

 

 

[old man emu]

This is what the Mechanic's Toolbox says:

 

The fit of bolts and holes can be defined by differences in diameter or by the amount of friction between the bolt and hole. The Air-Force-Airframe-Repair-Course (obsolete) defines a tight fit as "one in which a sharp blow of a 12 or 14 ounce hammer is required to move the bolt.

 

A bolt that requires a hard blow and sounds tight is considered to fit too tight.

 

A light drive fit is one in which a bolt will move when you hold a hammer handle against its head and press by the weight of your body.

 

A bolt which moves when pushed with your thumb is considered too loose.

 

For all modern repair work, diameter differences are the only reliable method to establish reliable fit.

 

Looks like the clearance of a lot of bolts is too loose.

 

OME

 

 

[fly_tornado]

Its a bit weird, as far as I can tell no one sells these drill sets the author mentions.

 

 

[old man emu]

I've got a drill set that contains Number drills, Letter drills and standard size drills in Imperial sizes. You can get them from any supplier of industrial tools.

 

OME

 

 

[spacesailor]

I have a drill set in 1/64", no probs with getting a tight fit, BUT now "they" say my hole aint round !, use a "reamer".

 

How many "reamer's in a 1/64" drill set 1/8" to 1/2"?

 

bryan

 

 

[old man emu]

Guess you've got to buy some reamers separately.

 

OME

 

 

[spacesailor]

After LOTS of years drilling holes, the only ragged ones were in thin material with large dia bit's, an easy fix with smaller dia drillbit & finish with half round file.

 

bryan

 

 

[facthunter]

All my life I've had the problem of 5 sided holes in sheet metal. The other day I sharpened the drill bits carefully with very little clearance angle at the cutting edge. Perfect.... the drill can't pull itself in too quick. After all those years.. Nev