The only hint they seem to give is in the ‘Troubleshooting’ section:

Bad cuts (not cutting square)
1. Feed pressure too great
1. Reduce pressure by increasing spring tension of the saw

… apart from that, it’s just

“• Let the weight of the saw provide the cutting force.”

MichaelG.

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Ref; __

https://www.clarkeservice.co.uk/manuals/woodworker/CBS45MD_Bandsaw_ISS_5.pdf

Edited By Michael Gilligan on 28/04/2022 06:47:33

Although there will be an optimum it depends on more than the cutting pressure: material, number of teeth per inch. and saw-speed come to mind.

I don't think the arm weight is critical: sufficient to cut rather than rub is 'good enough', and not so much pressure that teeth are forced deeper than their cutting depth. Also bad to apply so much force that the blade bends, breaks teeth, slips on the drive wheels, or stalls the motor!

In theory, I should change the blade and switch pulleys to increase or decrease blade speed to suit the material: Aluminum is much faster than Steel. In practice, I don't bother! Instead the bandsaw is set for mild-steel and allowed to get on with it. I don't fine tune the saw because I cut a variety of metals and diameters rather than a single size and material, and the benefit to me is taking the fag out of handsawing, not maximising production or minimising blade wear.

The bandsaw is the unsung hero of my workshop. Wartiest tool I own and I just take it for granted, yet it saves me lots of time and energy.

NDIYs suggestion of experimenting is probably the best way of adjusting the saw if you must. Rule of thumb is 1HP will remove 1 cubic inch of mild steel per minute. So, with a wattmeter on the input and a large lump of mild-steel in the saw, measure the volume of metal cut per minute. Arm weight is adjusted until the wattmeter shows the motor is near maximum rating, and then blade speed is adjusted for maximum metal removal. Comparing metal removed with the cubic inch per minute rule shows if the saw is cutting efficiently or not.  Note a sharp saw behaves differently to a blunt one!

Unfortunately, this optimises cutting efficiency by brutalising blade and machine. Cooling and lubricating the sawblade is mandatory when cut rate is maximised by industry, but not really worth doing on a small Clarke bandsaw. Instead, the life of the blade is extended by slowing down and decreasing arm pressure. This reduces the cutting load on the teeth and allows them plenty of time to cool down between cuts. It's also much kinder to the motor, which is unlikely to be continuously rated on less expensive saws. The saw's default setting should be fairly close: arm pressure somewhere in mid-range, not too light or too hard.

Industry put massive effort into optimising cutting efficiency, but my feeling is it's rarely necessary in a home workshop. Tools last reasonably well provided the operator avoids rubbing, mincing swarf, and gorilla cutting.

Dave

Edited By SillyOldDuffer on 28/04/2022 09:49:21

Hi Andrew, yes it is a little guess work, but if you cut a flat bar say 50 x 6mm, with it clamped in the vice by the 6mm dimension, you will need to have less pressure on the blade than you would if you held it in the vice by the 50mm dimension, not having enough pressure on the blade this way will give the effect of the teeth rubbing rather than cutting. You have be aware that these machines are a bit of a compromise, compared to an industrial machine, where the pressure can be controlled by hydraulics even during the cutting process, so in the case of large diameter round bar on an industrial machine, you can start of with a fairly light weight cut and then increase it as it gets towards the middle section and then back the weight off once it has past the middle section, thus prolonging blade life, but in my experience, nobody really does that in a work environment, as they just what to cut things off as quickly as they can and don't worry about how many times the blade has to be changed.

Regards Nick.

Edited By Nicholas Farr on 28/04/2022 13:08:44

likes along with smilies are an abomination + mess up usual technical notation, personally I’d also get rid of atavars – the site is IMO better for being significantly text based – leave childish things to the nursury.
The album mechanism has one significant benefit – the image is served from the same place as the text – too many ‘free’ image hosting sites disappear or revert either to charging or making their money by tracking individuals for future advertising purposes (obvious really as there is no such thing as a free lunch – this site gains because the users generate enough eyes to keep the advertisers happy)

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I do not wish to speak for Frances, but will respond to that question for myself:

The use of ‘Auto Smilies” on this forum is utterly crass, and yes we are forced to ‘use them’

[ or at least to use tedious work-arounds to avoid them ]

… They could be switched-off in software, but our hosts refuse to do so.

MichaelG.

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Probably a misnomer on my part, but they are the automatic substitution of a smiley for a perfectly innocent sequence of characters.

Try typing 1” in parentheses, without spaces

MichaelG.

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(1&rdquo

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But as gesture of goodwill, I will point you to a discussion elsewhere: **LINK**

https://www.mig-welding.co.uk/forum/threads/clarke-cbs45md-6×4-metal-cutting-bandsaw-modifications.58019/page-5

MichaelG.

I think Hopper summed it up nicely. As most of us are unlikely to make more than two similar cuts in a row its best to just find a setting that works reasonably well on the type of cuts you make and stick with that. For a single cut its likely to take as long to look up and change settings to suit blade, material, section, etc than it is to make the cut.

Luckily my Femi has constantly variable manual feed pressure so I don't have to worry about weights and springs.