Thread: Preston 30" Bandsaw Guides

Hi Vann,
I take it you want some new ones.
The round one could possibly be swapped over or end for end.
The other metal ones could be ground on a grinder, or make some wooden ones out of really hard wood.
They will work just as good.

Originally Posted by issatree

Hi Vann,
I take it you want some new ones.
The round one could possibly be swapped over or end for end.
The other metal ones could be ground on a grinder, or make some wooden ones out of really hard wood.
They will work just as good.

Hi issatree. I don't really know what I want yet . I guess I'd like to know if I can get spares. There are a couple of ring-in thumb-screws I might want to replace, and some of the wear strips are worn or broken ('though still useable).

aPresGstrips1.jpg aPresGstrips2.jpg three of these strips go in each guide - i.e. there are a total of 12 strips in the machine.
I thought these might be graphite (like carbon brushes) but they seem to be plastic. A hard timber would probably work - I wish I'd been able to score some lignum vitea.

I'm trying to find out all I can about the guides. I understand how to set them up, with the exception of the round piece, which appears to be a magnet within a sleeve . Does a magnet have any attracting force on a blade passing at 4000 ft/min.? Should it be in contact with the blade, or just clear? There are wear marks at both ends, so the magnet has been changed, end-for-end, in the past.

Cheers, Vann.

Originally Posted by Vann

aPresGstrips1.jpg aPresGstrips2.jpg three of these strips go in each guide - i.e. there are a total of 12 strips in the machine.
I thought these might be graphite (like carbon brushes) but they seem to be plastic.

quite probably they're made from Bakerlite -- which was a very common "plastic" from about 1900 through to 1960. If you remember the black light switches and power points they were made from Bakerlite. (my spelling may be off and it's Bakerlight )
Sorry, I don't know if it's still available.

I'm trying to find out all I can about the guides. I understand how to set them up, with the exception of the round piece, which appears to be a magnet within a sleeve . Does a magnet have any attracting force on a blade passing at 4000 ft/min.? Should it be in contact with the blade, or just clear?

my first guess is just clear

Originally Posted by ian

quite probably they're made from Bakerlite -- which was a very common "plastic" from about 1900 through to 1960. If you remember the black light switches and power points they were made from Bakerlite. (my spelling may be off and it's Bakerlight )
Sorry, I don't know if it's still available.

my first guess is just clear

Bakelite is a brand name for a type of thermo-setting plastic. So called because it uses temperature to set the plastic into a fixed shape and heating will not re-soften the polymer. Thermo-setting plastics are still in use and still available but are much less used today due to the more useful properties of thermo-hardening polymers, your more common plastics.

Does the plastic look to be fibre reinforced, can you see a woven pattern in it?

Looking in more detail at those photos they definitely look like termo-setting plastic aka Bakelite. I think hardwood would work a treat. You can get a tap of the same size as the screw and tap the hardwood for your screws.

John

Originally Posted by DSEL74

Does the plastic look to be fibre reinforced, can you see a woven pattern in it?

Hi DSEL. No, there's no woven pattern. I think ian and Yanis are on to it - it looks like they could be good olde breakie Bakelite .

It seems likely that the guides are of European origin, as the threads are metric, and New Zealand, like Australia, was all British Standard threads until the early 1970s, while Canada used mostly USA threads.

I've now renewed my search for lignum vitae (just in case).

Cheers, Vann.

There is similar material that looks like Bakelite sometimes used for gears and pulleys which has embedded fibre. I thought it might be that stuff.

I've got strip of lignin vitae in the stash somewhere Vann.
What size are you after? From memory this is a small roughed out bearing strip from a shipyard.
I can cut a bit off and send it with the brass buttons.
The old lawn bowls were lignum but although I have two I won't be cutting them up yet.
H.

Originally Posted by clear out

I've got strip of lignin vitae in the stash somewhere Vann.
What size are you after?

They're 10mm x 30.6mm cross section, and look to have been a maximum of 90mm long. I've been looking for an old bowling ball for a year or two, but always seem to miss out.

Cheers, Vann.

Originally Posted by DSEL74

There is similar material that looks like Bakelite sometimes used for gears and pulleys which has embedded fibre. I thought it might be that stuff.

Is that the "mica" board they use for electrical switchboards?

Originally Posted by Vann

I've been looking for an old bowling ball for a year or two, but always seem to miss out.

I just won an auction for a wooden bowling ball (finally). I hope that, whatever version of "lignum vitae" it is, it has the properties I want for bandsaw guides. Now if only I had a working bandsaw to cut it on...

Cheers, Vann .

Originally Posted by DSEL74

There is similar material that looks like Bakelite sometimes used for gears and pulleys which has embedded fibre. I thought it might be that stuff.

The product is called Novasteen. http://www.modeng.com.au/Products/Novasteen . Google 'Novasteen', you should find plenty of suppliers.

Alan...

Originally Posted by Vann

just won an auction for a wooden bowling ball (finally)...

My bowling ball arrived yesterday. It looks great in the sellers photographs...

aLignum.jpg

...but in the flesh it's only 100mm diameter . Next auction I'll ask the seller just how big the damn thing is .

However, I asked the same question about these guides on the UK forum, where a couple of posters said they looked like Chaco guides (Swiss).

I emailed Chaco and they said...

Originally Posted by Barbara @ Chaco

It seems like an old version of a CHACO bandsaw guides.
We can still deliver elements as per attached pictures. These are made of CHACO low friction material.
Please check if dimensions are correct. Width is given, because it is a pressed part. For the 90° ones you can have a different lengths if necessary.

aChacoGuide.jpg aChacoGuide90.jpg

As for the other spare parts, could you please name what you need and we will have a look if we have some left in stock. Pictures of the individual parts with dimension will always help...

So, if the prices aren't too high (Swiss , yeah right ) I may be able to afford some OEM parts.

Cheers, Vann.

Originally Posted by Vann

Is that the "mica" board they use for electrical switchboards?

Cheers, Vann .

No. Mica is a naturally occurring silicate that was extremely popular in the early days of electrical manufacture for use as an insulator in circuits and in capacitors (then called condensors). It was gradually replaced with synthetic materials. It is quite fragile and plastics were more durable and in the end had better electrical properties.

As a point of interest mica was also used in some places for windows before glass became a cheap commodity.

John