This listing is for the Oldham Coupling that is fitted to all SOHC engines in the vertical shaft assembly.  Two of these are required per engine, and we sell them in various thicknesses.  This listing is for the Std 3/!6" thickness version which was always fitted on the bottom bevel - but could also be fitted at the top (depending on specific engine/cambox height).  See also item number 0684 for various other thicknesses (i.e. top coupling should alwasy be measured on the top bevel to suit the compression ratio chosen for that engine and can vary).

These couplings are CNC manufactured by ourselves from very hard EN24T steel to a high tolerance.  The length of the tangs are the standard Norton SOHC size having being copied from good condition (un-molested) original items.  Two of these are required per SOHC engine, one is fitted underneath the vertical shaft and one fitted above.

These couplings were originally available in different thicknesses, it being the width of the centre section that can vary - this was to allow for different compression ratio's, where the barrel height may have been amended to allow for a higher or lower compression ratio, in which case it is the top Oldham Coupling that could be changed.

It should be noted that the bottom Oldham Coupling should always be the same width - 0.187" (3/16") - this is important as the vertical shaft has a lip on it at its base, that means it can rest on the inner ring of the lower bevel bearing.  Therefore if a thicker coupling was used it would mean the vertical shaft lip would sit proud of the bearing (and I assume this could place extra strain on the lower bevel gears - although how much risk there is of this I am not sure of. . . but it is the way Norton designed it, so must have been for a reason).

However, we offer a selection of different width couplings (both slimmer and thicker than the 'standard' size 3/16" type) to allow for if you are building an engine and need to adjust the coupling to allow for higher/lower compression ratio.  This is also very useful if assembling an engine from parts of different years, as there seemed to be many minor permutations of barrel height/crankcase height/conrod length/head to barrel spigot etc etc.  

This listing (0683) is for the standard 3/16" type coupling, go to Item 0684 if you require a top coupling of a different width.

Please Note:  Original Norton Oldham Couplings it seems were normally supplied hardened - i.e. you cannot run a file over them (although I have stripped a number of engines with what looks to be hard - but unhardened couplings fitted).  However - as part of manufacturing these couplings - we found that almost every original Norton vertical shaft had a degree of tolerance in the slot - the result being that it is difficult to find an ideal tang width that is a reasonable fit into all vertical shafts - they would either be too tight, or be too sloppy.  Because of this we have machined these couplings from a very hard (but unhardened) steel - to the most suitable original tang width.  Ideally - the oldham coupling tang should just feed into the bevel gear/vertical shaft with firm finger pressure (or a light tap with mallet).  In reality, it is not unusual to have a coupling that drops into the slot with no resistence - but there should be no perceptable 'slop' or sideplay - this indicating a worn slot.  Being hard but unhardened - if too tight to go into a slot, it is possible to lightly 'stone' these couplings (i.e. a vice mounted fine sharpening stone used in conjunction with light oil), to mate the face of the tang to the slot in the vertical shaft/bevel gear.  With  this in mind - it should be appreciated that these couplings may be less tolerant of high mileages or heavy use than original couplings, and owners should make occasional checks whenever possible - i.e. when removing cambox or head for regular maintenance to satisfy themselves all is good.  The customeer must accept this design consideration as part of purchasing these couplings  (and if required may decide to have them Nitride hardened - if felt necessary).

Measuring The Required Width For the Top Oldham Coupling 

So when measuring your engine on assembly - you should loosely assemble the engine with head/barrel/cambox/vertical bevel assemblies all fitted - but no couplings or vertical shaft fitted.  Once everything is tightened down, you should then measure the distance between the top and bottom vertical bevel gears.  You then subtract the length of the vertical shaft, the width of the bottom Oldham Coupling (3/16" as explained above), then the remainder of the measurement should be the width of the top coupling you require. 

The final important thing to remember when taking this measurement is that it is essential to allow a 'clearance' gap on each Oldham Coupling to allow for expansion - I normally ensure a minimum of 0.015" (i.e. 15 thou) on each coupling - remember to account for this clearance in your calculations (i.e. a total of at least 30 thou gap for both couplings). 

To accurately measure the distance you might find it is easier to make a telescopic adjuster - similar to the one shown in one of the photos in this listing.  I made this many years ago by boring a steel cylinder approx 0.5" in outer diameter, to allow an aluminium 0.250" shaft to slide up and down inside it, and a knurled bolt screwed in from the side, so the shaft can be tightened in position when fitted, then with a scriber you can mark the position, as you will need to loosen it and allow it to be removed for accurate measuring.  A tool like this can be invaluable for accurately measuring.  

Email us on sales@racingvincent.co.uk if this is not clear or you require more inforation.

Last two points when ordering these couplings:

1. You should ensure the coupling slides into the 'female' tang of the vertical shaft completely, so that the top face of the shaft/vertical gear is fully touching the middle section of the Oldham Coupling.  If you find the tang of the Oldham coupling touches the bottom of the slot of the vertical shaft/bevel gear - then it is very probable that your original vertical shaft/bevel gear has been modified!! - this was not unusual and I have seen it done on many occasions, I would expect that this means at some point in the past a previous owner has had to change parts or compression ratio and found it caused the vertical assembly to be too long for the cambox - therefore has shortened the end of the vertical shaft or gear to account for this.  If this is the case with your bike, it is possible to carefully grind the length of the Oldham Coupling, to shorten it slightly so the base is again in contact - however I must point out - if you do this it is at your own risk! (although it was not an uncommon thing for old owners to carry out, I cannot recommend it).  We will shortly be selling our own manufactured vertical shafts to original length's and these will be being made to fit the original tang length - as per these couplings.   And for further information - later DOHC engines were normally fitted with couplings with shallower tangs - approx 0.300" in length seems common.  If your shaft ends have been shortened to allow Oldham Coupling tangs of this length, it may be because at some point it was mixed with DOHC parts.

2. Wear of your vertical shaft or bevel gears and the fit of the Oldham Coupling?:  It is very difficult to be hardfast about what tolerance of fit is acceptable when fitting Oldham Couplings into the verical shaft/bevel gears.  Over the years I have measured very many original Norton Oldham Couplings and vertical shafts - and even when they have clearly been unused, there tolerances have varied by up to 2-3 thousandth of an inch??!!  However, as a yardstick - when assembling an engine, I normally like it when an oldham coupling tang will push into the vertical shaft/bevel gear slot with a firm finger pressure.  It should not lock up, but neither should there be any perceptable play once in place at all.  If there is perceptable 'slop' between the tangs then I would suggest your shaft has excessive wear.  We have manufactured the tangs on our Oldham Couplings to be in tolerance of the most common standard fit - and we then fitted to a variety of original shafts, and know they will either slide in or just require a light tap.  Final point to note - it is not unusual when fitting these into original shafts/gears to find that one end of the slot on the shaft/gear is a 'looser' fit than the other.  This seems normal - I think it was a consequence of this engine design that one side of the tang slot wears slightly more than the other - just make sure there is no perceptable 'slop' or rattle, indicating there is too much wear.

Not a cheap item, but reflects the difficulty to manufacture

New Batch Back In stock: April 2024

This is the Oldham Coupling that is fitted to all SOHC engines as part of the the vertical shaft assembly.  Two of these are required per engine, and we sell them in various thicknesses.  This listing is for the none stanard type for different complression ratios - which we can offier in various thicknesses, but should only be used on the top bevel housing.  For the bottom bevel housing you should always fit a standard thickness 3/!6" thickness version (and were often fitted on the top bevel housing as well), which we also sell - see Item 0683 for these.

Update April 2024: New batch now in, and all sizes back available.  We have also introduced a new thickness: 0684-6 which has 0.240" extra deep middle section, as this had been requested by some customers (not sure if this was an originally supplied thickness - but believe it has been found necessary by some owners building engines from mismatched parts - a very common theme for this popular engine type). 

These couplings are CNC manufactured by ourselves from very hard EN24T to a high tolerance.  The length of the tangs are the standard Norton SOHC size having being copied from good condition (un-molested) original items.  Two of these are required per SOHC engine, one is fitted underneath the vertical shaft and one fitted above.

These couplings were originally available in different thicknesses, it being the width of the centre section that can vary - this was to allow for different compression ratio's, where the barrel height may have been amended to allow for a higher or lower compression ratio, in which case it is the top Oldham Coupling that could be changed.

It should be noted that the bottom Oldham Coupling should always be the same width - 0.187" (3/16")  which is Item 0683 - this is important as the vertical shaft has a lip on it at its base, that means it can rest on the inner ring of the lower bevel bearing.  Therefore if a thicker coupling was used it would mean the vertical shaft lip would sit proud of the bearing (and I assume this could place extra strain on the lower bevel gears - although how much risk there is of this I am not sure of. . . but it is the way Norton designed it, so must have been for a reason).

However, we offer a selection of different width couplings (both slimmer and thicker than the 'standard' size 3/16" type) to allow for if you are building an engine and need to adjust the coupling to allow for higher/lower compression ratio.  This is also very useful if assembling an engine from parts of different years, as there seemed to be many minor permutations of barrel height/crankcase height/conrod length/head to barrel spigot etc etc.  

This listing (0684) is for the non-standard thickness couplings - and the table below shows the different types we offer, both thinner and thicker than the standard type.  Go to Item 0683 if you require a coupling of the standard 3/16" width.

Please Note:  Original Norton Oldham Couplings it seems were normally supplied hardened - i.e. you cannot run a file over them (although I have stripped a number of engines with what looks to be hard - but unhardened couplings fitted).  However - as part of manufacturing these couplings - we found that almost every original Norton vertical shaft had a degree of tolerance in the slot - the result being that it is difficult to find an ideal tang width that is a reasonable fit into all vertical shafts - they would either be too tight, or be too sloppy.  Because of this we have machined these couplings from a very hard (but unhardened) steel - to the most suitable original tang width.  Ideally - the oldham coupling tang should just feed into the bevel gear/vertical shaft with firm finger pressure (or a light tap with mallet).  In reality, it is not unusual to have a coupling that drops into the slot with no resistence - but there should be no perceptable 'slop' or sideplay - this indicating a worn slot.  Being hard but unhardened - if too tight to go into a slot, it is possible to lightly 'stone' these couplings (i.e. a vice mounted fine sharpening stone used in conjunction with light oil), to mate the face of the tang to the slot in the vertical shaft/bevel gear.  With  this in mind - it should be appreciated that these couplings may be less tolerant of high mileages or heavy use than original couplings, and owners should make occasional checks whenever possible - i.e. when removing cambox or head for regular maintenance to satisfy themselves all is good.  The customeer must accept this design consideration as part of purchasing these couplings  (and if required may decide to have them Nitride hardened - if felt necessary).

Measuring The Required Width For the Top Oldham Coupling 

So when measuring your engine on assembly - you should loosely assemble the engine with head/barrel/cambox/vertical bevel assemblies all fitted - but no couplings or vertical shaft fitted.  Once everything is tightened down, you should then measure the distance between the top and bottom vertical bevel gears.  You then subtract the length of the vertical shaft, the width of the bottom Oldham Coupling (3/16" as explained above), then the remainder of the measurement should be the width of the top coupling you require. 

The final important thing to remember when taking this measurement is that it is essential to allow a 'clearance' gap on each Oldham Coupling to allow for expansion - I normally ensure a minimum of 0.015" (i.e. 15 thou) on each coupling - remember to account for this clearance in your calculations (i.e. a total of at least 30 thou gap for both couplings). 

To accurately measure the distance you might find it is easier to make a telescopic adjuster - similar to the one shown in one of the photos in this listing.  I made this many years ago by boring a steel cylinder approx 0.5" in outer diameter, to allow an aluminium 0.250" shaft to slide up and down inside it, and a knurled bolt screwed in from the side, so the shaft can be tightened in position when fitted, then with a scriber you can mark the position, as you will need to loosen it and allow it to be removed for accurate measuring.  A tool like this can be invaluable for accurately measuring.  

Email us on sales@racingvincent.co.uk if this is not clear or you require more inforation.

Last two points when ordering these couplings:

1. You should ensure the coupling slides into the 'female' tang of the vertical shaft completely, so that the top face of the shaft/vertical gear is fully touching the middle section of the Oldham Coupling.  If you find the tang of the Oldham coupling touches the bottom of the slot of the vertical shaft/bevel gear - then it is very probable that your original vertical shaft/bevel gear has been modified!! - this was not unusual and I have seen it done on many occasions, I would expect that this means at some point in the past a previous owner has had to change parts or compression ratio and found it caused the vertical assembly to be too long for the cambox - therefore has shortened the end of the vertical shaft or gear to account for this.  If this is the case with your bike, it is possible to carefully grind the length of the Oldham Coupling, to shorten it slightly so the base is again in contact - however I must point out - if you do this it is at your own risk! (although it was not an uncommon thing for old owners to carry out, I cannot recommend it).  We will shortly be selling our own manufactured vertical shafts to original length's and these will be being made to fit the original tang length - as per these couplings.   And for further information - later DOHC engines were normally fitted with couplings with shallower tangs - approx 0.300" in length seems common.  If your shaft ends have been shortened to allow Oldham Coupling tangs of this length, it may be because at some point it was mixed with DOHC parts.

2. Wear of your vertical shaft or bevel gears and the fit of the Oldham Coupling?:  It is very difficult to be hardfast about what tolerance of fit is acceptable when fitting Oldham Couplings into the verical shaft/bevel gears.  Over the years I have measured very many original Norton Oldham Couplings and vertical shafts - and even when they have clearly been unused, there tolerances have varied by up to 2-3 thousandth of an inch??!!  However, as a yardstick - when assembling an engine, I normally like it when an oldham coupling tang will push into the vertical shaft/bevel gear slot with a firm finger pressure.  It should not lock up, but neither should there be any perceptable play once in place at all.  If there is perceptable 'slop' between the tangs then I would suggest your shaft has excessive wear.  We have manufactured the tangs on our Oldham Couplings to be in tolerance of the most common standard fit - and we then fitted to a variety of original shafts, and know they will either slide in or just require a light tap.  Final point to note - it is not unusual when fitting these into original shafts/gears to find that one end of the slot on the shaft/gear is a 'looser' fit than the other.  This seems normal - I think it was a consequence of this engine design that one side of the tang slot wears slightly more than the other - just make sure there is no perceptable 'slop' or rattle, indicating there is too much wear.

Not a cheap item, but reflects the difficulty to manufacture

Below is the different width of top couplings we can offer (only for use on top bevels.  You would not use these widths on your lower bevel assembly unless your vertical shaft/lower vertical bevel gear has been altered): 

This is the steel collar that fits over the shaft at the end of the top or bottom bevel, its purpose being to contain the Oldham Coupling that fits into the tang at the end of the bevel gear shaft.

This is a 'Standard Fit' collar.  Price is each

Ideally the collar should be a 'nip' fit over the shaft, where it is lightly tapped on (I use an alloy drift with hammer, with the bevel gear bottom face sitting on an alloy/wood block). For the lower bevel gear this also seems to serve a second function, in that it stops the lower bevel gear dropping through gravity onto the crankshaft bevel gear.

Not sure if this was Norton's original intention (or actually if it makes any significant difference!), but for this reason, I always try and make the collar a nip fit on the shaft. Because there seems to have been a considerable variation of SOHC Bevel Gear shaft diameter variation (i have seen up to 1.5 thou variation on the quite considerable number of gears I have measured - even unworn shafts) we have made these collars to be a good fit over the bevel gears we manufacture - which we believe to be the most correct diameter - i.e. a nominal 0.7485" - 0.749".

If the collar is not an ideal fit over your own gear:- if too tight - you can carefully 'flapwheel' the inside diameter of the collar, until it taps on, or, if too lose - use a small quantity of 'Bearing Fit' to retain the collar. Note: we also sell a one thou undersize collar (Item 0470), so if you have an original bevel gear and you think the shaft diameter is less than above, then probably best to go for item 0470 (or buy one of each . . . and you can have a choice!)

This is the steel collar that fits over the shaft at the end of the top or bottom bevel, its purpose being to contain the Oldham Coupling that fits into the tang at the end of the bevel gear shaft.

This version is one thou (0.001") undersize on original fit, as the original shafts can vary fractionally with wear and usage.  Price is Each.

Ideally the collar should be a 'nip' fit over the shaft, where it is lightly tapped on (I use an alloy drift with hammer, with the bevel gear bottom face sitting on an alloy/wood block).

For the lower bevel gear this also seems to serve a second function, in that it stops the lower bevel gear dropping through gravity onto the crankshaft bevel gear. Not sure if this was Norton's original intention (or actually if it makes any significant difference!), but for this reason, I always try and make the collar a nip fit on the shaft.

Because there seems to have been a considerable variation of SOHC Bevel Gear shaft diameter variation (i have seen up to 1.5 thou variation on the quite considerable number of gears I have measured - even unworn shafts). This particular item is an alternative to item 0460, it being approximately one (1) thousandth of an inch tighter on the shaft than 0460 - i..e. ideal for bevel gears with a nominal diameter of 0.7475" - 0.748" or less. if the collar is too tight - you can carefully 'flapwheel' the inside diameter of the collar, until it taps on, or, if too lose - use a small quantity of 'Bearing Fit' to retain the collar. Note: If you think your shaft is a greater diameter than above, then item 0460 may be better - or if unsure buy one of each!

This is the very important twin row, self centering bearing that was originally fitted in both top and bottom bevel housings in all International and early Manx engines (SOHC and earlier DOHC engines).

They are self centering, because they allow for the vertical shaft to be moved off centre slightly, and therefore it facilitates the cambox being 'swivelled' out from under the top frame tube, when working on the engine.  It also allows for any small discrepancy in the cambox being out of line with the bottom bearing housing.  They were originally made by top UK bearing manufacturer RHP (previously known as Hoffman - in case you are removing an old bearing from an original bevel housing and find one of these bearings stamped 'Hoffman').

Update January 2024:  As I am sure most owners of SOHC Norton engines know - these bearings have been obsolete for many years now, and we have been relying on sourcing old stock at very high prices.

We sold the last of our current stock in July 2023, however, I have just managed to obtain a small batch of genuine new RHP bearings from the one supplier in the country who holds some - but they know how rare they are and therefore the price is very high - I am sorry this is the case, but there are no alternatives - and actually I have managed to negotiate and maintain the same price they were last offered at in 2022.

I am told these will not be made again by RHP (these are 'New Old Stock' which is quite usual for bearing suppliers - who always hold obsolete bearings in 'new' condition) - so once they are gone, they are gone.

Note: these bearings were originallly supplied in greaseproof paper in 'rolls of 5' - see the photograph of a previous batch we supplied, which were supplied to me in that way, in the old 1970's yellow RHP box, which we then split up.  Just like this latest 2024 batch, it is standard practice for bearing suppliers to unpack the rolls of 5 bearings - and wrap them individually in a plastic bag and a bearing box - as these are done.  This latest 2024 batch have been supplied pre-split into individual boxes - the box is marked 'HOF' (referring to the old makers name - Hoffman, but the bearings themselves are marked 'RHP', so  rest assured they are the genuine article!

Additional Information on SOHC (and early DOHC) Bevel Bearings:

Because they have not been available for many years, whatever stock is still out there is very expensive to obtain - the bearing suppliers know this!   So worth noting - for the top bevel housing, it is possible to use a single row 'none self centering' replacement of the same dimensions, which I can sometimes also supply (see Item 0006), however, it is really important that the correct twin row bearing is used on at least the bottom housing . . . failure to do this could mean you canot remove the cambox with the engine fitted in the frame! And if you can afford it, it is best to go for this bearing top and bottom.  You must accept though that if fitting a (cheaper) single row, non self-centering 0006 bearing in the top - movement off verticle of the cambox when removing from a frame may be slightly more restricted.  Both do the same job once in place though.

Final hint on fitting these bearings (because at the cost of them you dont want to waste them!!): I have fitted these bearings into housings many times over the years and I have found it is very important not to knock the inner bearing, or accidentally press it excessively, so that the inner race pushes 'out of centre' to the point where the balls totally lose touch with the outer race. Although the inner race will allow this . . . even with a brand new bearing, it is possible when pressing the inner race back into line that one of the small balls could be pushed out of its bronze cage - and be very difficult to get back in place, particularly if the bearing is now mounted in the bevel housing with no access to the underside. Therefore the message is - handle with great care!  It is also very important to fit the dished washer (Item No. 0007) under the lower bearing - which was designed specifically to capture any errant balls that do drop, so as to avoid them dropping into the bevel box and crunching the gears.  My old mentor Titch Allen told me that this design and bearing kept Norton's Service Department in business for many years!. Finally, whenever stripping the engine down, it is always worth checking this area (and bevel box) to make sure no loose balls have made their way out.  The best advice I can give is - always handle with care and never take them off centre any more than absolutely necessary!

- Unfortunately the original type Twin row self centering bronze caged ball bearing is now obsolete and no longer easily available (item no 0005), therefore extremely expensive. I can also supply this single row (non self centering) variety, also manufactured by RHP, as a cheaper alternative to fit to the  TOP cambox bevel housing only, instead of the original twin row type.

The bearing still performs exactly the same function - but as this bearing has a fixed track (i.e. it is not of the 'self centering' variety) it means the vertical assembly is slightly less flexible, and therefore more fiddly to remove the cambox when the engine is in the frame.  However, I have been told by other Norton friends and customers in the past that it is a comon/cheaper replacement and does still allow some movement.  

NOTE: this bearing should not be fitted in the bottom bevel housing, where it is essential the original twin row self centering type is used. Please bear in mind that if using this bearing in the top housing, you should be very careful not to move the cambox off centre any more than necessary when stripping down, as it will force the bottom bearing off centre 

Update April 2020:  Almost as hard to source now as the original twin row bearing 0005 (although normally much cheaper when I can get them), I have managed to obtain a handful more of these as well.  However - if you can afford it and we still have them in stock - I would still advise buying 0005 in preference to these, as they allow more movement when removing the cambox.

Essential when rebuilding your engine to ensure that the lower vertical bevel gear has the correct backlash and position in relation to the crankshaft bevel gear, these lower bevel shims fit between the timing case housing and the lower bevel housing

Fitted in conjunction with the timing case shim, the ideal positioning is acheved when the gears are in line and there is a just perceptable gap (backlash) between teeth.

This is for a complete set of 5 shims in the following sizes :

0.5mm//0.3mm0.2mm/0.1mm/0.05mm. Note - shim steel is now supplied in metric thicknesses, but these are offered in the nearest equivelant to the old Imperial sizes that were commonly used - i.e.

- 0.5mm = 0.021" or 21 thou (for some reason the actual thickness is 0.53mm which = 21 thou) 

- 0.3mm = 0,012" or 12 thou 

- 0.2mm = 0.008" or 8 thou

- 0.1mm = 0.004" or 4 thou

- 0.05mm = 0.002" or 2 thou (but see note below for these)

Packed in Duck Oil to protect from rusting. with slight saving when bought as set of 5 shims.

Update Feb 2020: All sizes now back in stock again - however, please note: the thinnest shim (0.05mm shim) has a slightly larger hole (i.e. the coarse bevel housing type, which has a slightly bigger centre hole - sold seperately as 0862) - as it is very difficult to produce in this thin size - my shim maker only makes this thickness of lower bevel shim in the one type - they work just as well as the others though in practice, as they locate by the stud holes.

Essential when rebuilding your engine to ensure that the lower vertical bevel gear has the correct backlash and position in relation to the crankshaft bevel gear, these lower bevel shims fit between the timing case housing and the lower bevel housing

Fitted in conjunction with the timing case shim, the ideal positioning is acheved when the gears are in line and there is a just perceptable gap (backlash) between teeth.

This listing is for a single shim which we can supply in the following 4 sizes :

0.5mm//0.3mm0.2mm/0.1mm/0.05mm. Note - shim steel is now supplied in metric thicknesses, but these are offered in the nearest equivelant to the old Imperial sizes that were commonly used - i.e.

- 0.5mm = 0.021" or 21 thou (for some reason the actual thickness is 0.53mm which = 21 thou) 

- 0.3mm = 0,012" or 12 thou 

- 0.2mm = 0.008" or 8 thou

- 0.1mm = 0.004" or 4 thou

- 0.05mm = 0.002" or 2 thou (but see note below for these)

Put a note stating which size you require when placing the online order.  We also sell complete sets of 5 shims (see listing 0326B)

Note: we do also have a few of the very thin 0.05mm thickness shims - but these have a slightly larger central hole (approx 51mm), which were of the type fitted to later DOHC Coarse Bevel housings.  They are still work just as well.  However, because these are limited in quantity - please email us for availability if you require one of this thickness.  See picture of 5 shims to see the 0.05mm shim

Update Feb 2020: All sizes now back in stock again 

Essential when rebuilding your engine to ensure that the upper vertical bevel gear has the correct backlash and position in relation to the camshaft bevel gear, these upper bevel shims fit between the cambox shell casting and the upper bevel housing -

Fitted in conjunction with the camshaft bevel gear shim, the ideal positioning is acheved when the gears are in line and there is a just perceptible gap (backlash) between teeth.

This is for a complete set of 5 shims in the following sizes :

0.5mm/0.3mm/0.2mm/0.1mm/0.05mm. Note - shim steel is now supplied in metric thicknesses, but these are offered in the nearest equivelant to the old Imperial sizes that were commonly used - i.e.

- 0.5mm = 0.021" or 21 thou (for some reason the actual thickness is 0.53mm which = 21 thou) 

- 0.3mm = 0.012" or 12 thou

- 0.2mm = 0.008" or 8 thou

- 0.1mm = 0.004" or 4 thou

- 0.05mm = 0.002" or 2 thou

It is common practice to measure initially with no shims fitted, then add one or multiple shims to reach the desired positive backlash, measuring each time shims are added or subtracted  

Packed in Duck Oil to protect from rusting, with slight cost saving over buying individually

Essential when rebuilding your engine to ensure that the upper vertical bevel gear has the correct backlash and position in relation to the camshaft bevel gear, these upper bevel shims fit between the cambox shell casting and the upper bevel housing -

Fitted in conjunction with the camshaft bevel gear shim, the ideal positioning is acheved when the gears are in line and there is a just perceptible gap (backlash) between teeth.

This is for a shingle shim in any of the following sizes (please state which size required when placing online order) :

0.5mm/0.3mm/0.2mm/0.1mm/0.05mm. Note - shim steel is now supplied in metric thicknesses, but these are offered in the nearest equivelant to the old Imperial sizes that were commonly used - i.e.

- 0.5mm = 0.021" or 21 thou (for some reason the actual thickness is 0.53mm which = 21 thou) 

- 0.3mm = 0.012" or 12 thou

- 0.2mm = 0.008" or 8 thou

- 0.1mm = 0.004" or 4 thou

- 0.05mm = 0.002" or 2 thou

It is common practice to measure initially with no shims fitted, then add one or multiple shims to reach the desired positive backlash, measuring each time shims are added or subtracted  

Sets of all 5 shim thicknesses also available as a set with slight cost saving - see Item 0327B. Packed in Duck Oil to protect from rusting