Jump to content
Strawberry Orange Banana Lime Leaf Slate Sky Blueberry Grape Watermelon Chocolate Marble
Strawberry Orange Banana Lime Leaf Slate Sky Blueberry Grape Watermelon Chocolate Marble
Sign in to follow this  
Tom Veck

M11 bolts? Do they even exist?

Featured Posts

The bolts at the rear of our prop shaft recently sheared off. We went to buy some new bolts for it and were told we needed 60mm high tensile M11 bolts. They didn't have any, so we have fitted M10 for now and she is running okay. I cannot for the life of me find any M11 bolts anywhere online or elsewhere. Does anyone know where I can get them, or what I should do?

 

Thaks

Tom

Share this post


Link to post
Share on other sites

They do exist, but they are a special, so will be vastly more expensive than either an M10, M12, or 7/16"

Check with your local nuts and bolts supplier - they will probably have to buy a thousand to supply your handful, and will charge you accordingly....

Share this post


Link to post
Share on other sites

The bolts at the rear of our prop shaft recently sheared off. We went to buy some new bolts for it and were told we needed 60mm high tensile M11 bolts. They didn't have any, so we have fitted M10 for now and she is running okay. I cannot for the life of me find any M11 bolts anywhere online or elsewhere. Does anyone know where I can get them, or what I should do?

 

Thaks

Tom

Depends how much you trust the person telling you this. I'm inclined to agree with RLWP. Far more likely to be 7/16" imperial bolts.

 

Are you related to Tom Vek?

 

 

MtB

Share this post


Link to post
Share on other sites

I've never seen an 11mm (M11) bolt. I wouldn't say there's not one. I too would go with 7/16 easy to get and much better fit than 10mm.

Share this post


Link to post
Share on other sites

When I was in engineering screws/bolts such as these were always described as "b*stard size" for obvious reasons, go with 7/16 it will do the job.

 

Phil

Share this post


Link to post
Share on other sites

The bolts at the rear of our prop shaft recently sheared off. We went to buy some new bolts for it and were told we needed 60mm high tensile M11 bolts. They didn't have any, so we have fitted M10 for now and she is running okay. I cannot for the life of me find any M11 bolts anywhere online or elsewhere. Does anyone know where I can get them, or what I should do?

 

Thaks

Tom

 

 

M11 bolts exist, but this is not a recommended size, so only really big users will be able to get them easily. (Automotive companies have their own reasons for using non-preferred sizes!)

 

As has already been said 7/16" is close (11.11 mm) so may well fit. If not I'd either stay with 10mm and keep an eye on it or enlarge the holes to take 12mm which is another preferred size. The drive force should not be transmitted by the bolts, but by friction between the two halves of the coupling. The bolts are only there to clamp the halves together and produce enough friction.

 

N

Share this post


Link to post
Share on other sites

M11 bolts exist, but this is not a recommended size, so only really big users will be able to get them easily. (Automotive companies have their own reasons for using non-preferred sizes!)

 

As has already been said 7/16" is close (11.11 mm) so may well fit. If not I'd either stay with 10mm and keep an eye on it or enlarge the holes to take 12mm which is another preferred size. The drive force should not be transmitted by the bolts, but by friction between the two halves of the coupling. The bolts are only there to clamp the halves together and produce enough friction.

 

N

 

Some couplings, especially older ones, rely on the bolts to locate the coupling halves together. Ideally these should have 'fitted' bolts with precision shanks. Modern couplings generally have a locating spigot and corresponding recess on the two halves, so loose fitting bolts are perfectly OK.

If the OP's coupling doesn't have this locating spigot he really should try to find the right size of bolt. I agree, much more likely to be 7/16" than M11.

If it really is M11 (I would be amazed), then he could get some 7/16" bolts skimmed down to that size, there should still be enough strength left in the threads.

 

Tim

Share this post


Link to post
Share on other sites

This has been really helpful so thank you everyone. I will get some high tensile 7/16" bolts and try fitting them on instead of the M10's which may only be stainless anyway.

 

Persumably I can use locking nuts and tighten as much as possible to stop this happening again?

Share this post


Link to post
Share on other sites

This has been really helpful so thank you everyone. I will get some high tensile 7/16" bolts and try fitting them on instead of the M10's which may only be stainless anyway.

 

Persumably I can use locking nuts and tighten as much as possible to stop this happening again?

 

Yes Locking nuts, and plain washers either side, but do check the alignment of the coupling- the two halves need to be parallel before the bolts are tightened. If not there will be a cyclical variation in load and the bolts may fail from fatigue, especially if they are very tight.

 

 

To check pull the coupling up by hand (no bolts) and insert a feeler gauge at the top, from the bottom and from either side. The gap should be the same all round within a thou or so. If not the coupling is out of line.

 

If there is a flexible coupling the test still applies- everything will last longer if it's all in line (except possibly needle roller bearings in a propshaft).

 

 

N

Share this post


Link to post
Share on other sites
On 10/04/2013 at 23:45, Biggles said:

I've never seen an 11mm (M11) bolt. I wouldn't say there's not one. I too would go with 7/16 easy to get and much better fit than 10mm.

7/16" looks like 11.11mm, so fairly close to M11.

Share this post


Link to post
Share on other sites

Clearly the bolts exist, they're building a new junction onto it this year and they've got to make sure it holds together:

https://www.essexhighways.org/highway-schemes-and-developments/highway-schemes/m11-junction-7a.aspx

 

Maybe the bolts are made in Harlow, after all they say this new junction is:

"supporting business growth in the area"

Hardly ever been on the M11 myself, I'm from south of the river guv.

  • Happy 1

Share this post


Link to post
Share on other sites

I wonder if the M10 bolts lasted the last 7 years, or if he ended up with 7/16...

  • Horror 1

Share this post


Link to post
Share on other sites
16 minutes ago, WotEver said:

I wonder if the M10 bolts lasted the last 7 years, or if he ended up with 7/16...

According to his profile, the OP joined on 10/4/13, last logged in to CWDF on 11/4/13 and posted twice, so I doubt we shall ever know. Life is full of these little mysteries!

Jen

Share this post


Link to post
Share on other sites
5 hours ago, Peter X said:

Clearly the bolts exist, they're building a new junction onto it this year and they've got to make sure it holds together:

https://www.essexhighways.org/highway-schemes-and-developments/highway-schemes/m11-junction-7a.aspx

 

Maybe the bolts are made in Harlow, after all they say this new junction is:

"supporting business growth in the area"

Hardly ever been on the M11 myself, I'm from south of the river guv.

 

The ones they'll be sourcing at the moment, will be "lockdown" bolts.

 

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.