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Posted by Richard Edwards on September 6, 2008, 2:12 pm
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On Sat, 6 Sep 2008 10:50:47 -0700 (PDT), jontom_1uk@hotmail.com wrote:
>On 6 Sep, 18:11, Richard Edwards
>> Since I have had my Denford Viceroy I have never been happy with the
>> belt drive. This is an A section Link Belt, a similar setup to the
>> Boxford.
>> The Belt suffers as Backgear oiling is preferred from points over the
>> gears, the oil therefore gets on the belt!
>> Even though the manual says oil I feel the best option for the future
>> is grease the layshaft and use gear spray on the gears from time to
>> time.
>>
>> I stripped it apart today and noticed that the belt is not sitting
>> down into either the top or bottom pulley grooves. In fact there are
>> one and a half link thicknesses standing proud. Theoretically three
>> link sides should always be in contact IMHO.
>> The belt that I removed shows polishing soley on about 8mm of the
>> thinner "tail", ie from the innermost part of the groove.
>> The pulleys appear to be original Denford (certainly the top pulley on
>> the backear setup) and an A section belt is supposedly the standard.
>> Groove angle seems to be 38 degrees from a quick check
>> I have done some calculations and it appears that an SPZ belt will
>> handle the loadings. Obviously the SPZ will sit fully in the groove
>> hopefully allowing a full drive.
>>
>> I suppose that a 13mm belt may have been fitted as opposed to an A
>> section, however I doubt that 12.7 compared to 13mm would make that
>> much difference.
>>
>> Has anyone seen anything similar before?
>> Can anyone suggest my best course of action?
>>
>> --
>>
>> Richard
>>
>> Email address is valid but remove burrs before sending!
>
>
>Richard
>
>I'm no expert on these belts but having just checked my Boxford the
>belt is slightly less than one link thickness proud of the pulley
>outer diameter on each pulley. It never slips and has run like that
>without problem for the last two years. It is dry though. The tension
>on these belts is critical and it almost sounds if yours does not have
>sufficient tension to pull the belt into the groove fully. If my
>memory serves me with an A link belt (new) when you put the belt round
>the pulleys to find the length you then remove 1 in 11 of the links to
>set the basic tension; the belt is in effect 9% shorter than the free
>length.
The problem on the Viceroy is then clipping it back together again!
>The other way is to measure the force to deflect the belt when
>fitted depending on the centre distance of the shafts. There is a
>chart about somewhere but I would need to find it for you.
No need you helped with a link a long while ago, I now have the pdf on
my system.
>I know that
>the (high in my opinion) tension when fitted to my S7 gave me some
>cause for concern and I returned to the standard belt. The belt on my
>Boxford is very tight but I am less concerned due to the spindle and
>layshaft bearing arrangement. The other issue I have had when fitting
>new link belts is that they require frequent re-tensioning as they
>settle in through the first few months of operation, depending of
>course how many hours they run. All assuming of course that your belt
>is in fact the correct section for the pulleys.
That is the thing that cocerns me most. The facxt that your Boxford
only shows less than one link indicates that I have something awry. I
will check a neighbors Boxford.
Regards
>
>Keith
--
Richard
Email address is valid but remove burrs before sending!
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> belt drive. This is an A section Link Belt, a similar setup to the
> Boxford.
> The Belt suffers as Backgear oiling is preferred from points over the
> gears, the oil therefore gets on the belt!
> Even though the manual says oil I feel the best option for the future
> is grease the layshaft and use gear spray on the gears from time to
> time.
>
> I stripped it apart today and noticed that the belt is not sitting
> down into either the top or bottom pulley grooves. In fact there are
> one and a half link thicknesses standing proud. Theoretically three
> link sides should always be in contact IMHO.
> The belt that I removed shows polishing soley on about 8mm of the
> thinner "tail", ie from the innermost part of the groove.
> The pulleys appear to be original Denford (certainly the top pulley on
> the backear setup) and an A section belt is supposedly the standard.
> Groove angle seems to be 38 degrees from a quick check
> I have done some calculations and it appears that an SPZ belt will
> handle the loadings. Obviously the SPZ will sit fully in the groove
> hopefully allowing a full drive.
>
> I suppose that a 13mm belt may have been fitted as opposed to an A
> section, however I doubt that 12.7 compared to 13mm would make that
> much difference.
>
> Has anyone seen anything similar before?
> Can anyone suggest my best course of action?
>
> --
>
> Richard
>
> Email address is valid but remove burrs before sending!