Author Topic: Wooden brake blocks  (Read 7037 times)

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Offline Chris

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Wooden brake blocks
« on: 12 Jul 2016 at 12:36 »
Over the years there has been mention of wooden rear brake blocks for use on belt rims on early Douglas models and from comments made they can apparently be quite effective. In one previous post there is mention of mahogany but from experience can anyone recommend the best type of wood to use for this purpose and how and say how it compares in terms of braking performance with the slab rubber material sold by the VMCC. Chris

Offline Black Sheep

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Re: Wooden brake blocks
« Reply #1 on: 12 Jul 2016 at 13:03 »
I have heard mahogany mentioned. The VMCC slabs wear alarmingly quickly. I too will be investigating a wooden brake block in due course.

Offline ian scott

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Re: Wooden brake blocks
« Reply #2 on: 12 Jul 2016 at 22:39 »
Chris you might recall I made a wooden brake block for my 2&3/4 on the Australian 100 year rally. It works really well. It is progressive but not powerful however. I made the timber block longer as my problem with the rubber block was that it was jamming on switch like through the servo effect. That first timber brake block has not worn out yet. It does show some wear though. I simlpy got a scrap of hard timber of unknown species from the local hardware. I can say with some certainty it some type of eucalypt.

Offline Ian

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Re: Wooden brake blocks
« Reply #3 on: 13 Jul 2016 at 04:24 »
From memory the one on mine we made from Jarrah - has been on the whole time we have used the bike and works quite well.

Offline graeme

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Re: Wooden brake blocks
« Reply #4 on: 13 Jul 2016 at 10:15 »
It is jarrah Ian - I remember the conversation at the time

Offline ian scott

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Re: Wooden brake blocks
« Reply #5 on: 13 Jul 2016 at 11:19 »
I think most Australian hardwoods, due to their extreme hardness and lack of oiliness would work well.

Offline Chris

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Re: Wooden brake blocks
« Reply #6 on: 14 Jul 2016 at 07:28 »
Thanks for comments so far. Jarrah, from a search of the ineternet seems to a be a uniquely Australian timber and only available in the UK from ebay in the form of polished plaques, boxes and souvenirs from Australia. However, the description of Jarrah being a reddish close grained hardwood does suggest a similarity to mahogany; so in the absence of further advice  I am tempted to give that a try. Chris.

Offline ian scott

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Re: Wooden brake blocks
« Reply #7 on: 14 Jul 2016 at 12:06 »
Jarrah is much harder than most mahoganies Chris.

Offline Chris

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Re: Wooden brake blocks
« Reply #8 on: 14 Jul 2016 at 17:08 »
Thanks Ian and others. I have also had a personal message suggesting that cherry and apple woods have been used in the past with good results. Chris.

Offline shuswapkev

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Re: Wooden brake blocks
« Reply #9 on: 14 Jul 2016 at 21:17 »


I have stacks of it here in queensland
 easy enough to post ...  a block to play with...there are different types of gumtree....some are a lot harder than others...  while apple and other stone fruit trees wood are similar in some ways to Aus. type hardwood......  I reckon gum type timber would be far better....  used to live in British Colombia...  made lots of stuff from both timbers...  have to cut thru a lot of fruitwood to get a good block...
  I used to like making artsy type stuff out of wood...until I started wasting my time on greasy old murdercycles...

Offline John Simpfendorfer

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Re: Wooden brake blocks
« Reply #10 on: 14 Jul 2016 at 21:58 »
Hi Chris,
An excellent timber to make brake blocks out of is " Tallow wood ". This timber was used for door treads and window sills ,in the building industry .It is hard wearing  and a little oily in texture. Use a darker colour hard wood for your brakes, as the pink and lighter coloured timbers are mostly softer.
John.

Offline Alan

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Re: Wooden brake blocks
« Reply #11 on: 14 Jul 2016 at 23:55 »
Many years ago a TS I found in a shed (in the UK) and unused for decades,had a wooden rear brake block...Even after restoration
of the bike I continued to use the block and was still progressive and effective..Was a dark hardwood ( type unknown).

Offline Bob M

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Re: Wooden brake blocks
« Reply #12 on: 15 Jul 2016 at 00:14 »
Machinery's Handbook, (the engineers bible) recommends poplar as the best for wooden brake blocks. To quote, "Poplar gives a high coefficient of friction, and is little affected by oil". It then goes on to list in order of effectiveness, poplar, oak, beech and elm but warns elm drops off if affected by oil. It is also careful to say "In all case the motion is in the direction of the fibres in the wood."

Of course it's a US/English publication and all of these are common Northern Hemisphere woods that their engineers would have no problem sourcing with no mention of Australian hardwoods.

Can I ask why no one seems interested in the blocks of 'Retarding Medium' the English VMCC sells? Apparently they had legal issues if they called it brake block material.
 
Cheers, Bob

Offline John Simpfendorfer

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Re: Wooden brake blocks
« Reply #13 on: 15 Jul 2016 at 03:40 »
Hi Chris,
I forgot to mention , in my previous e-mail, that if I was in USA. I would use Hickory.
This timber was used a lot for wheel spokes in sulkies, buggies. Also for steam bending of hood bows and shafts.
John.

Offline Black Sheep

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Re: Wooden brake blocks
« Reply #14 on: 17 Jul 2016 at 06:55 »
The VMCC retarding medium has a poor reputation. Rapid wear and not a lot of friction being mentioned. I did mention brake blocks for the 2 3/4 to our local veteran guru and he recommended wood rather than retarding medium. Must spend a happy hour with the band saw.

Offline tck

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Re: Wooden brake blocks
« Reply #15 on: 18 Jul 2016 at 07:14 »
My 1925 2-3/4 has a mahogany brake block made out of a chair arm made longer to prevent 'overcenter' locking I only wish the belt drive rim was more concentric-a job for the winter...?

Offline Jim47

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Re: Wooden brake blocks
« Reply #16 on: 29 Jul 2016 at 12:45 »
"The Vintage Motorcyclists' Workshop" by Radco (pg 34) suggests poplar and beech.  Radco prefers beech.  On this basis I have used English Beech (sourced from a member of a specialist wood working group here in Australia) and it seems to work as well as expected in retarding the progress of my CW.

Offline douglas1947

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Re: Wooden brake blocks
« Reply #17 on: 02 Aug 2016 at 12:00 »
I would use NOT a hard wood!
Im shure the choise of POPLAR have good results. A soft wood has a better friction than a hard one!
I restored for cariages and had allways good results with poplar brake "pads".

Michael