On Thursday, August 20, 2020 at 11:33:19 PM UTC+1, petek wrote:
On Thursday, August 20, 2020 at 10:08:22 AM UTC+1, Brian Gaff (Sofa) wrote:
It could be true that they are some kind of standard product, but do be
aware that Nylon comes in different harnesses too, and unless you know what
they used it might not last long if it was user filable, if that is a word.
Do they have to be Nylon? I'd have thought metal ones would outlast the
device.
Brian

--
--
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Dave Liquorice" wrote in message
...
On Tue, 18 Aug 2020 21:50:02 +0100, T i m wrote:

The blade guide rollers on my c.40 year old Burgess bandsaw are
badly worn and because of it's age replacement guide rollers
appear
unavailable. They appear to be made of nylon, 13mm o/d, 5mm i/d,
10mm long.

Measured with what OOI?

I'm sure Steve on "The Repair Shop" would just turn up a suitable bit of
nylon in the wink of an eye, but I haven't got a lathe like he has!

Few have these days.

Why do you need a lathe?

Get hold of a suitable short length of rod (eBay?) of say 15 mm dia,
cut a 10 mm length, carefully drill a 5 mm hole in the centre, fit a
snug bolt and nut through the hole with washers each side. Firmly fix
some abrasive paper on to a hard flat surafce. Put end of bolt in
power drill and with the drill running rub the nylon squarely on the
abrasive until you have the desired dia. Perhaps starting quite
coarse if you have a lot to remove then progressively finer to the
finished dia.

If you have a pillar drill with a table that can rotate fixing the
abrasive to the vertical table that can be swung against the
nylon/bolt in the chuck should produce a very good result. With less
agro than trying it handheld.

Or even have good dig about on eBay for rollers. Perhaps intended for
some thing else, garage doors? But I think they are nearer 20 mm dia
and not sure how they are fixed to the bar. You get the idea though.
B-)

--
Cheers
Dave.



The replacement rollers ("spacers") I ordered on Ebay haven't arrived yet so I thought I'd clear up one or two queries in the meantime.

I'll try to describe the guide roller arrangement for those who are not familiar with 40 year old Burgess bandsaws! They are quite simple and I have seen more sophisticated arrangements on more recent bandsaws.

The top and bottom guide assemblies are identical. Each one comprises a rear roller and a front roller whose longitudinal axes are perpendicular to the blade.
The rear roller is steel and has a concentric groove. the blade runs in this groove and the back edge of the blade runs against the bottom of the groove thus supporting the blade against the thrust from the work piece. The sides of the groove are in close contact with the sides of the blade and help to prevent the blade twisting. These rollers on my saw are OK.

The front roller is made of Nylon or a similar plastic and when set up correctly runs very close to, but not touching, the teeth of the blade. If set up correctly it does not rotate as it is not in contact with the blade. It's purpose is to maintain the blade in position in the groove in the rear roller. Over the years this roller has been set incorrectly, too close to the blade, and has been chewed up somewhat by the teeth. (I should add that the saw had a previous owner). Indeed one of the rollers has been cut into two. These are the rollers I'm trying to replace, during a general clean up and refurb of the saw.

While the dimensions of the nylon rollers don't appear to be critical, I don't fancy trying to turn them up on my woodturning lathe in view of their size and the thickness of the skin on my fingertips. I'll only have a go at this in the last resort. I'm hoping that the ones I've ordered will do the job.

With regard to Tim's comments about imperial/metric sizing of the rollers I am surprised that they appear to be metric given the age of the saw, 1970/80's, and it's (I think) British design. The measurements I took with my vernier caliper seem to be exact multiples of millimetres rather than imperial equivalents.

Cheers
Pete
Well, to all those who are still interested after my rambling post yesterday, the new spacers I ordered turned up (forgive the pun) in the post this morning and I'm pleased to report that they do the job exactly. A bit sloppy on the id but should be OK. I had to buy a min order of 10 and only needed 1 so I've now got 9 going spare. If there are any Burgess BBS20 owners out there who would like one or two, please get in touch.

Thanks again for all the help and constructive messages.

Cheers
Pete