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. 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! Or as much skill for that matter! Has anybody any idea how I could get a couple made? Cheers
Measured with what OOI?
Few have these days.
It's mostly practice.
Any job like that is likely to cost more than the saw cost to replace (these days) so it's down to finding someone with one and some nylon stock that wants to do it for the S&G's.
I wonder how well some 3D printed ones would work? I'm only setup for PLA and they would be very easy to design / print [1] but it depends how much friction was on them and how hot they got as to how long they might last?
If we are confident in the dimensions I'm happy to print you some (4?) and stick em in the post?
Failing that, when I get round to the end of my own list and near my lathe ...
Cheers, T i m
[1] Open Sketchup Draw circle radius 2.5mm Draw concentric circle radius 6.5mm Delete inner 'hole'. Drag ring up 10mm to form tube. Export as .stl. Open Repetior Host and select previous file. Duplicate 1 to 4 off. Select 100% infill. Slice with Slic3r Save .gcode file to SD card. Put SD card in 3D printer and select file, print. 10 mins later, pick up 3d objects created out of nowhere!
badly >> worn and because of it's age replacement guide rollers appear
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-)
Any good?
That's the first reason ... ;-)
And the second. ;-)
And the 3rd. ;-)
4th ..Yes, if you were in the back of India or on a desert island I'm sure with enough material to work with you could eventually get a pair of rollers that are concentric and worked.
A lathe makes the whole process that much better / quicker. ;-)
I've probably got a stick of nylon that diameter that I could first bore out 50mm x 5mm, part off at 10mm lengths and be done before you had found the bolt that fitted nicely. ;-)
But then I have a lathe ... ;-)
Cheers, T i m
Thanks for 3 very constructive replies.
Tim, the o/d was measured with vernier caliper, but a fraction of a mm eith er way may not be critical as the roller o/d is not in contact with the bla de if set up correctly . The i/d is to suit a 5mm screw. Length again measu red with v. caliper but not critical. Thanks for the offer to print a coupl e which I will hold in reserve, see reply to Fredxx below.
Dave, yes I had thought of doing something like that on my wood turning lat he but was hoping to find something off the shelf.
Fredxx, thanks for the link. I had been searching for nylon bar or tube - i t didn't occur to me to search for "spacer"! They have some with 12.7 o/d x 5.6 i/d x 25mm long, so I've ordered a pack of 10 for a couple of quid. Ma y be a sloppy fit on the 5mm screw but could be OK.
Thanks again for your responses, I'll let you know how I get on.
Pete
ther way may not be critical as the roller o/d is not in contact with the b lade if set up correctly . The i/d is to suit a 5mm screw. Length again mea sured with v. caliper but not critical. Thanks for the offer to print a cou ple which I will hold in reserve, see reply to Fredxx below.
athe but was hoping to find something off the shelf.
it didn't occur to me to search for "spacer"! They have some with 12.7 o/d x 5.6 i/d x 25mm long, so I've ordered a pack of 10 for a couple of quid. May be a sloppy fit on the 5mm screw but could be OK.
Thanks for your further reply Tim. As I said, can I hold your offers in res erve in case the ones I've ordered turn out to be no good?
Cheers Pete
Understood. I was asking because I was wondering if something that old may have been made with Imperial measurement parts?
That might have been a 1/4"? If you had a digital vernier couldn't you get that on whatever the guide runs on as that sounds like it's the one part that might need to be a reasonably good (free to turn easily but not sloppy) fit?
Understood.
Of course. ;-)
Once we know we have the key dimension(s) it would be very easy to print as many as you need. ;-)
Cheers, T i m
p.s. I believe mine is a Burgess (I'll check when I go down the workshop next) like this one:
Wot he said (both DIY and eBay)
Ideally you want a bench stand for your drill and I'd probably make up two or three on a single length of bar, and then saw them up afterwards.
If you start with something larger in OD than you require, and drill the right sized hole in it, then it does not matter if you are a bit off.
I find its easy to get a very accurate and concentric ring of stuff using nothing more than a fixed disc sander, and a circle truing jig[1]
- which is basically a small bit of ply or MDF that you can fix your work to such that it can spin round a pivot, and can be offered to the sander.
Probably not allot in it TBH
[1] I made a "posh" version - a 8" square (ish) bit of 3/4" MDF with a bar fixed to the underside, that fits snugly into the slot on the disc sander's table so it will stay a fixed distance from the disc (the simpler version - just use a clamp).Then I routed a rebate perpendicular to the disc, and ripped a strip of wood that fits snugly into the rebate, flush with the top.
To use it, drill your blank, and then partly drill the strip of wood at the end with the same drill. Remove the drill, invert it and push it through the work and into the strip. Set it up on the sander and tap the strip toward the disc such that the corners of the work will touch the spinning disc. Turn the work through a full circle round the drill bit pinion, and then advance the strip. You will end up with a concentric part.
(the non posh version - bit of wood and a clamp or two)
Here using a Forstner bit as a pinion:
No, true, assuming you can then hold said eccentric object rigidly enough to bring the OD into concentricity.
Sure, anything 'can' be done but still requires quite a few tools and 'jigs'.
Eh? It's *the* tool for that job, if not injection molding, especially if you have to also make / setup jigs etc?
I just stick the stock in the 3jaw, face up the end, centre drill, drill ID, slide out to live centre, do OD, part off the lengths ... done and very true / concentric?
'Disk sanders table ...' ... ;-)
Router ... ;-)
Saw table ... ;-)
Peasy.
And you accurately control the od how?
Neat. I can see how it could work but question how good it might be for even nylon, compared with a lathe ... and especially for anything longer (tube V washer etc)?
Not that Pete's guide rollers necessitated any super high tolerance but if you have that to hand ...
I can't remember the exact setup but I was wondering if you couldn't find some suitable ID/OD bearings to fill the gap and let it run on them?
Cheers, T i m
I was referring to the speed aspect - and for the level of accuracy required. If you can tolerate a couple of thou, then you can sand to that.
Jigs can be *really* basic if only doing a one off job. I made posher versions because I need to true up a number of bandsaw cut cogs.
Indeed, I am familiar with a lathe :-)
As I said, scrap of wood, and a clamp will do it for a one off.
You are rotating the work on an accurate spindle (i.e. the drill bit that made the clearance hole though it) at a fixed distance from the sander. Once spun through 360 degrees, you will have a very accurate circle concentric with the pivot.
ISTR it was only 10mm required - should not be a problem.
Yup that was my first suggestion - its actually what my bandsaw uses anyway.
(...)
Clamp? that's posh...
I have done, for round bits of wood, i.e. tabletops, using an edge sander (a belt sander with the belt running horizontally):
Pinion is a bit of nail, not penetrating, just into the underside. The jig: the pinion is the finished radius from the (straight) edge of a largish bit of scrap wood. The workpiece sticks out over the edge. Offer the jig with the edge of the workpiece to the sander, and sand until the edge of the jig just touches the sanding belt. Then, holding the scrap wood in place, rotate the workpiece into the belt (into! otherwise the belt will snatch). Continue round.
This takes practice, but one hand controls the rotation and the other how close to the belt you are. So it allows you to sand off a lot, so you can zip around with the bandsaw and not have to hew to the line. And it is really fast to set up. Not using a clamp means that if it does snatch (and it will the second you get impatient and less than gentle feeding the material) everything just moves away a bit and nothing goes flying, nor does the belt break...
For the bandsaw, I'd look for a ball bearing, maybe: "Ball Bearing 695 ZZ 5x13x4 mm", and stack two with a bit of washer. First price I see is 0,81? per piece, if buying four.
Or look at a "drill bushing", and see if any suit.
Thomas Prufer
Sure, but I still question the concentricity (within the general tolerance etc). If you are rotating something by hand the rate at which (and to what depth) can vary as a function of how fast you present the work to the cutter. So, even if you rotate it several times there may be bits that may have been 'overcut' as you first presented them that are then lower than the surroundings. Not a problem of making a woodwork washer but might if concentricity could be relevant (like guide rollers that subsequently 'stick' in the same places and then gain further flats). I'm not saying your solution doesn't work, it obviously would / does, just that I wouldn't use it against turning or 3D printing (if either were available and the materials suitable etc).
Oh, I'm sure for certain scales and styles of work they can be more than adequate.
Just checking. ;-)
That will often have an element of slack on it and so wouldn't typically be used as a mandrel on any similar lathe based job.
'Very accurate' ... for that level of equipment / use. eg, I'm not sure NASA would use it for *anything*. ;-)
Knowing how even leaning on a toolpost can make a difference, and certainly any backlash on pretty well any of it, again I can't see that other than for an approximation of 'true'.
My metal cutting horizontal bandsaw certainly does but then they are twisting the blade though 45 degrees (and managing them back).[1]
I think on my small bench bandsaw (I believe a Burgess as per the OP's) the 'guides' are simply there to stop the blade wandering sideways (too far) in use. They don't hold the blade tight enough to stop it twisting a bit if you rotate the work too fast etc.
Cheers, T i m
[1] It was the 6" Clarke one from Machine Mart:Bought when I was making the 3 off 6' 6" steel doors and fame to replace the up-and-over that came with my sectional workshop.
It was doing really well till one of the blade management bearings failed and from inspection I found they were all 'cheap and nasty'. Replaced with SKF or similar and they have lasted 10x longer already. ;-)
I can't quite visualise how you would do that - if the pinion distance from the "cutter" is fixed and rigidly supported, then you can't cut any closer than that distance - same as with something spinning on a lathe and the cutter held on the tool post.
Sure a lathe will be more accurate, but if you ain't got one, and the sanding method is "good enough", then not much to worry about.
IME, if you use the shank of the drill for your mandrel, its close enough in wood.
(if worried and you have a set of tap drills, drill your holes 0.1mm undersized)
Perhaps for a guide bush on one of their bandsaws? :-)
Well that's true of any engineering. You use a three jaw chuck, or make a measurement with a caliper etc, or even make a cut on a hot workpiece those will also be approximations. The important question is will if be fit for purpose when done?
Yup, guides not actually touching the blade is generally best practice - they should only contact under cutting loads.
Yeah, MM stuff does seem to vary in quality from just about ok to not as good!
Awful things. I got one for free once. Eventually concluded the reason the blades snap so readily is nothing to do with the tighter radius of 3 wheels , but rather the absence of tyres plus absence of anything to wipe sawdust buildup off the blade. Wipe it very frequently in use & it was ok, though t he cutting capacity was pathetic.
NT
Except when the tool 'digs in' and draws the cutter harder into the job? As I'm sure you know, very little of what we consider 'rigid' actually is under all circumstances and so if when you rotate your piece against the sanding disk, given you will likely be doing so at slightly different speeds (stop start) and potentially with different amounts of material to remove, the 'machine' will give / flex slightly.
If you are turning then stop ... then carry on, you will see that line where you stopped because the tool with settle further into the work, cutting more than when the tool was moving over the job and being pushed away slightly as it does so (to every action there is an equal and opposite reaction). ;-)
Yes, if. If I was making a thin wooden washer to go behind a drawn knob in wood I might well use your technique because it would be adequate for that level of accuracy. If I was doing anything that was any level of engineering solution I think I would look for another solution if I didn't have a lathe. Maybe it's because I have one I now can't consider any other way (other than 3D printing etc).
Yes, agreed ... and maybe any other 'plastic' material that could close up / flex slightly whilst being drilled so the hole stays slightly small.
Check.
Hehe.
Quite.
Agreed.
Agreed.
TBF, most of the (possibly selected as to be 'likely to be ok') I've bought from there has been fine, or certainly reasonable VFM and before the same stuff (often re-badged) was available on ebay.
Things like magnetic welding clamps, the cast iron grinder pedestal, or even the 10 tonne hydraulic press where basic robust engineering are all that's required. The 6" bandsaw is still pretty 'tight', even after a fair amount of use but only after the supplied bearings were replaced with proper ones (about the only bit of it where they seem to or were able to cut corners).
Cheers, T i m
Or get quite a few made and flog the surplus on ebay?
Brian
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
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
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