Making A bolt for my motocycle

A bit of advise need

I need to make a bolt for my motorcycle that secures the engine to the frame... It is a Flange Bolt, M12, 1.25 Fine Thread. Thread Length of 56mm with a smooth shaft of 126mm, (Over all length of 194mm), Flange of 24mm and a 16mm Hex Nut on the end...

The reason I need to make this bolt is because because I want to add some brackets on to the bike and there is not enough bolt length on the original bolt... These bolts are unique to Triumph....

The bolt will need to be able to deal with Heat, Vibrations, Weather and being Torqued up tight...

So My Questions are:

1) I have had it mentioned that it will need to be made from High-Tensile Stainless Steel HSS..... Is this correct?
2) How easy is this material going be to machine?

3) Will normal cutting tools on a laithe and large amatuer milling machine cope dealing with this material?

4) Will a standard die be able cut a thread on this material?

5) It has been suggested that as the bolt is used with a flange nut I could use a length of round bar and thread both ends. Then thread the flange nut on the bar, followed by welding the flange nut on one end? Is this a feasible idea or will it be an inferrer compromise?

6) Where would be the best place to get 12mm round HSS Bar?

All advice welcome... Thanks

Personally I would use EN16t for the bolt and make some stainless dome nuts, easy to make, or if you do want to reproduce the original but a little longer use A2 304 Stainless,light cuts are not recommended with stainless, it has a tenancy to work harden, if your timid it will know! and fight you all the way, I find it better when threading this stuff with a die, to go at it quite quickly but stop every two turns or so to let the die cool or maybe use coolant, even so your dies will have a reduced life...

M Machine in Darlington usually have it

HTH

Shaun

I've replaced a few M10 and M12 bike engine long mounting bolts and used stainless as have loads of other people I know with no problem. They are usually M10x1.25 and M12x1.5 fine threads but I just bought standard thread ones, used a penny washer turned down to the OE diameter if need be instead of a flange and nyloc nuts to secure. Never had one loosen or cause any problem.

They are hard to find at that length I get mine from Steve's stainless, you should be able to get a 200mm long one then cut to length and add any extra thread length with a die.

**LINK**

Hi Jamie

En57T is a high tensile stainless that is commonly used. it's no more difficult to machine than En16T/En24T and of similar strength. I bought some from M Machine, some other ME suppliers also supply this material.

Edit - I have not had any problem cutting threads using standard high speed steel dies using a good cutting lubricant. For turning I have used carbide tools but high speed steel can be used at low speed.

Nigel

Edited By tractionengine42 on 22/07/2014 08:35:44

Jamie,

For clarity HSS is 'high speed steel' and is for making cutting tools. It is relatively brittle and totally unsuitable for fixings.

There are both high-carbon and stainless steels that will suit you purpose that can be turned with suitable tools as folks have described above.

Another option is to buy an over-length bolt with a suitably long smooth section and cut it to length.

There are specialist suppliers of bike bolts and nuts who may have what you want off the shelf.

Neil

Thanks for the responses so far...

I am struggling to find M12 x 200mm or longer A2 304 Stainless Bars...

Does anyone know of any online businesses?

I work in an area where there is no mobile signal and can't get hold of anyone during the day

Hi Jamie,
Here is just one on many Ebay sellers . I used the search phrase "threaded rod stainless M12"

Les.

Aluminium warehouse supply stainless steel 304 and 316 see **LINK** for 304

Bob

There has been a lot of discussion with regard to the use of stainless on classic bike forums. I would suggest a visit to your bike specific forum. It has been known for "replaced with stainless" bolts to fail in "hard work" situations. Cosmetic issues over practicality?

Mike

.

A very good point, Mike

It would certainly be wise to check the specification of the original bolt.

Jamie: You gave a good physical description in your opening post ... but are there any markings on the bolt head? [maybe 8.8 or some-such].

MichaelG.

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Edit:

Jamie; a quick look here suggests that the grade might be 10.9 ... in which case I would be very wary about any stainless substitute.

Edited By Michael Gilligan on 25/07/2014 09:42:09

Personally I would not use stainless on critical mounting bolts unless of the same strength as the original ones.

Be wary of so called high tensile bolts unless they have the strength markings on the head at least equal to the replaced ones.

Paul

I think the HSS was a slip of the digit for HTS Neil. I changed all the fastenings on my Moto Guzzi Le Mans to stainless including some that had to be manufactured (in the workshop) many years ago without detriment. The main ones for engine to frame were supplied by a bolt manufacturer who forged the head onto stainless rod/bar the threads then being machined onto the end so it was a BOLT and not a SETSREW.

The design of the bike means that the engine is cradled in the frame as opposed to being underhung or part of the frame design (A La Vincent) so in the event of a failure (??????) the engine can't drop out, loading being in the shear stress plane rather than tensile stress.

There are grades of high tensile stainless steels used for fastenings (500 series) BUT, they do rust so beware.

You haven't mentioned what bike you are working on but if it is of far eastern design, beware of the head sizes, in some applications they have done a "Model ingineer" by using a head hex size for the next lower diameter fastner - M8 Hex on an M10 bolt etc..

Regards Ian.

I believe that he said "unique to Triumph"?

Mike

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... of which there are many models.

MichaelG.

Replacing HT fixings on things like suspension and brakes I can see the point and though I've never done it myself I know of plenty that do on classic and modern machines and I've yet to hear of a failure on any of the many bike forums I visit.

Engine mount bolts clamp up tight with spacers with no free length to stress a particular area of the bolt ,I have and would still use stainless for them in a cradle frame.

Jamie - ring Steve's stainless as I posted earlier, he does the long bolts.

Here is a handy reference sheet for the common head-markings.

MichaelG.

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Jamie ... Are you still there, or have you deserted us for another forum.

The third post on that thread appears to answer my question.

Quote: "There is also no markings on the bolts"

MichaelG.

Edited By Michael Gilligan on 26/07/2014 08:43:59

I have used EN24T recently for some stressed parts on bikes and on machines. It machines very nicely using carbide tools or HSS tools. I have cut threads, rather than use a die, mostly because of the nature of the thread I required, but a HSS die will work. The steel would need further heat treatment afterwards, to give it the hardness/strength characteristics to match a high tensile bolt, and while the machining is easy, getting the heat treatment done is a pain.

Stainless is not an appropriate material for a highly stressed job, as it is "softer" and less strong than most of the EN16/24/57 steels. Stainless sets up corrosion against steel and aluminium. I see lots of fasteners in stainless, now, including many small diameter fasteners, but I don't believe it's a good choice for every situation, especially small (M2) fasteners with an internal hex (like a grub screw). Some grades of stainless are not corrosion-proof.

Marcus

It's never a good idea, whenever possible, to use highly stressed bolts as a mounting for extras. I mean things like cylinder head bolts holding a coil bracket or engine mounting bolts holding an exhaust bracket.

Hi

Still here..

There are no makings on the bolt...

The bike is a Triumph Thruxton (Modern versions of Triumph Bonnevile that has a cafe race style fairing)

I have tried to up load some pictures to my album but it won't let me post them into this thread.. I have uploaded picture of the bolt, nut, bolt in location and a picture of a simular bike with a fairing with location of bolt and fairing bracket market on it. So please view my album here : http://www.model-engineer.co.uk/albums/member_album.asp?a=32181

Edited By Jamie Jones on 26/07/2014 10:00:47