Ted's daft question of the week ?

[McCabe-Thiele (Ted)]

I really am not getting to grips with Honda metric bolts & threads.

The sump has some 11 bolts listed in the parts manual as Bolt, Flange, 6 x 40 part number 95700-06040.

My sump bolts do not have a flange (if that's a built in washer) on them or a loose washer so they may have been repaced or it's a superseded part number.

I assume 6 x 40 is the thread size and length. Is that automatically m6 fine thread?

Is the length 40mm from the flange base to the end of the thread or is it the overall length including the bolt head.

It looks to be as cheap to fit new SS bolts as having the old ones Zinc Plated your comments & observations welcome please ??

[Bryanj]

M6 will be m6x1 and the length is measured from under the head(or flange) to the end of thread. NOTE:- when purchasing,
BOLTS  have a none threaded portion under the head
SETSCREWS are fully threaded

[McCabe-Thiele (Ted)]

M6 will be m6x1 and the length is measured from under the head(or flange) to the end of thread. NOTE:- when purchasing,
BOLTS  have a none threaded portion under the head
SETSCREWS are fully threaded

Thanks Bryan that means presumably as its's a smallish diameter it's automatically a coarse metric thread?

[Bryanj]

Not really Ted under the iso system each diameter has a prefered or standard pitch and then one or two alternatives.
A lot of the smaller metric are 1mm till you get right down then its 0.75

[McCabe-Thiele (Ted)]

Not really Ted under the iso system each diameter has a prefered or standard pitch and then one or two alternatives.
A lot of the smaller metric are 1mm till you get right down then its 0.75

I have the idea in my head that a fine thread would be in steel with coarse in alluminium so clearly not the case then?

[Bryanj]

Fine thread usualy to help stopping loosening ina vibration prone area but also in general courser threads in soft metal for a stronger root

[philward]

M6 will be m6x1 and the length is measured from under the head(or flange) to the end of thread. NOTE:- when purchasing,
BOLTS  have a none threaded portion under the head
SETSCREWS are fully threaded

Thanks Bryan that means presumably as its's a smallish diameter it's automatically a coarse metric thread?

Ted, don't worry too much about M6, in my experience of the 500/750 sump bolts is that they are standard M6 x 1mm pitch (not fine)
I personally haven't come across anything other than standard M6 on the bikes I've built. There is probably an odd m6 fine application but it will be rare I think. M8 tend to be standard pitch, its M10 upwards that I have found is the metric fine.

[McCabe-Thiele (Ted)]

Ted, don't worry too much about M6, in my experience of the 500/750 sump bolts is that they are standard M6 x 1mm pitch (not fine)
I personally haven't come across anything other than standard M6 on the bikes I've built. There is probably an odd m6 fine application but it will be rare I think. M8 tend to be standard pitch, its M10 upwards that I have found is the metric fine.

Thanks Phil I will try to remeber that for future.

It seems cheaper to replace the sump bolts with SS ones than have the originals Zinc plated that's why I asked about the threads.

[Spitfire]

Don't know if this will help but I found it when I renewed a lot of bolts on my 750F1, it was from the Custom Fasteners website.

IMPORTANT - PLEASE READ BEFORE ORDERING METRIC BOLTS.
Metric bolts in M4, M5, M6, M7 and M8 diameters are suitable for both European and Japanese motorcycles and cars.

However, M10 in the standard 1.50 pitch are only suitable as replacements on European machines. They will not fit Japanese vehicles which use their own specialised fine thread. Please see the next section in the catalogue for our specially produced range of M10 and M12 fine thread bolts for Japanese vehicles.

M10(1.25 pitch) and M12(1.25 pitch) FINE THREAD METRIC BOLTS
For use on Japanese motorcycles and cars. M10(1.25) bolts have a 17mm spanner size, M12(1.25) bolts have a l9mm spanner size. The Japanese often
use a smaller size head on their bolts, so please check there is sufficient clearance for the standard size head we supply, before ordering.


 NOTES ON METRIC BOLTS
M4 fits spanner size 7mm. M4 thread pitch is 0.70mm.
M5 fits spanner size 8mm. M5 thread pitch is 0.80mm.
M6 fits spanner size 10mm. M6 thread pitch is 1.00mm.
M7 fits spanner size 11mm. M7 thread pitch is 1.00mm.
M8 fits spanner size 13mm. (Japanese M8 bolts use 12mm spanner size). M8 thread pitch is 1.25mm.
M10 fits spanner size 17mm. M10 thread pitch is 1.50mm.

Cheers

Dennis

[philward]

Thats what I have done - standard and flanged SS bolts are available cheaply.
If you want to go for originality on the engine covers you can see, try megapack on ebay, they do SS JIS (japanese 'philips' headed screws) - I've used these thoughout the builds I've done wherever there was originally a cross headed screw - here's an example

https://www.ebay.co.uk/itm/324584873287?hash=item4b92c41d47:g:JUYAAOSwnVVZmAnR

To save having to buy a pack with more in than I need of one length, I normally buy the longest I need and cut them down - and remember to use a specific JIS (Japanese Industry Standard) screwdriver. Back in the day, as a teenager, I used to butcher the screw heads using ordinary Phillips screw drivers - and blame the 'cheapo jap metal'!
Megapack have a range of other interesting bits and pieces
Standard caveat - use copper grease on the SS bolts
Not what you asked but hope it helps!

[fogrider]

As well as the advice to use copper grease on SS bolts, I was told decades ago to not put stainless steel nuts on SS bolts. Have one or the other in mild steel ( ZP no problem ). A  vehicle restorer, he told me SS has a grain, SS on SS 'rags' when you try to undo them. It's true, I found out by experience, having forgotten his advice. The SS nuts with SS bolts on my old lorry mudguard brackets would NOT come off, they ragged up and I had to cut them all off, some expensive bolts too !

Some copper grease these days is rubbish too, I've taken to using silicone grease which is not too expensive from plumbers merchants. Invisible too....

[McCabe-Thiele (Ted)]

Don't know if this will help but I found it when I renewed a lot of bolts on my 750F1, it was from the Custom Fasteners website.

IMPORTANT - PLEASE READ BEFORE ORDERING METRIC BOLTS.
Metric bolts in M4, M5, M6, M7 and M8 diameters are suitable for both European and Japanese motorcycles and cars.

However, M10 in the standard 1.50 pitch are only suitable as replacements on European machines. They will not fit Japanese vehicles which use their own specialised fine thread. Please see the next section in the catalogue for our specially produced range of M10 and M12 fine thread bolts for Japanese vehicles.

M10(1.25 pitch) and M12(1.25 pitch) FINE THREAD METRIC BOLTS
For use on Japanese motorcycles and cars. M10(1.25) bolts have a 17mm spanner size, M12(1.25) bolts have a l9mm spanner size. The Japanese often
use a smaller size head on their bolts, so please check there is sufficient clearance for the standard size head we supply, before ordering.


 NOTES ON METRIC BOLTS
M4 fits spanner size 7mm. M4 thread pitch is 0.70mm.
M5 fits spanner size 8mm. M5 thread pitch is 0.80mm.
M6 fits spanner size 10mm. M6 thread pitch is 1.00mm.
M7 fits spanner size 11mm. M7 thread pitch is 1.00mm.
M8 fits spanner size 13mm. (Japanese M8 bolts use 12mm spanner size). M8 thread pitch is 1.25mm.
M10 fits spanner size 17mm. M10 thread pitch is 1.50mm.

Cheers

Dennis

Thanks Denis that is very useful I've saved the info on a Word document for future reference.

[McCabe-Thiele (Ted)]

As well as the advice to use copper grease on SS bolts, I was told decades ago to not put stainless steel nuts on SS bolts. Have one or the other in mild steel ( ZP no problem ). A  vehicle restorer, he told me SS has a grain, SS on SS 'rags' when you try to undo them. It's true, I found out by experience, having forgotten his advice. The SS nuts with SS bolts on my old lorry mudguard brackets would NOT come off, they ragged up and I had to cut them all off, some expensive bolts too !

Some copper grease these days is rubbish too, I've taken to using silicone grease which is not too expensive from plumbers merchants. Invisible too....

Here it's termed differetly but same issue!
https://www.essentracomponents.com/en-gb/news/product-resources/how-to-prevent-galling-on-stainless-steel-bolts