Darn knobs - I give up

[Ukastronomer]

Almost impossible to find replacement knobs for mounts so making mine.

Anyone remember the great film Shane.............

This is my tree stump

2" alloy rod, harder to cut than you think

[brian nordstrom]

:question: Don't cut your finger off !!! .

Anyway look for an electronics store that sells ' Radio / Stereo Knobs ' you will find what you need .

Brian.

[Ukastronomer]

I have but I want them 2.5" across and can't find any that wide :(

[alval]

It looks a bit dry. Try using some wd40 or similar on the blade and work and it will stop the alloy sticking to the teeth clogging up the blade. Also use the coarsest tooth blade you can find. Still its a monumental effort, that cut is generally what they make machines for. But sometimes you goto do what you goto do to get things done.
Al

[mental4astro]

In the spirit of Al's post, I rub the saw blade across a cake of soap before cutting, and periodically pul out blade, clean of grit, re-soap and keep cutting. The soap is a little less messy than WD40 or other oil lube.

I do the same to files with soap when filing aluminium. File teeth are much easier to clean with a wire brush and the quality of the file cutting is restored.

[Saturnine]

If it is any consolation Jeremy, a few months ago I hacksawed through an 4", 102mm solid aluminium round bar, for a tripod pier extension project. Took me about 2 hours all up and used an 18T blade and the occasional spray of WD40 to help lubricate the cutting action. Was good exercise for the arms and shoulders, so it can be done with perseverance and a bit of a rest now and then.

[Ukastronomer]

WOW! for the hint. I have THREE more to do today

Will try that

[Ukastronomer]

Thanks both, appreciated.

I didn't know about lubrication, I thought it may simply mean the saw stopped working as it cut out the friction

Thanks all

[alval]

I noticed in your other post you are tapping these as well. Wd40 or similar is good for that too. Back in the day kerosene was the lubricant for machining, tapping, drilling aluminium, but Wd40 in a can is just easy to apply in small doses gives a better finish on threads and holes.
Al

[Ukastronomer]

Thank you, I stopped using WD40 because it is not good on bikes and started using others, but I have some and will try it later when I do three................THREE more, .............. wish I had a lathe :(

[Ukastronomer]

First of all thanks for the great advice.

Now I have a question.

I bought these, as mentioned above I got blades as what i had were old, but they are so smooth almost as if there are no teeth, combined with WD40 I cut another in less than a THIRD the time of yesterday.

How?

[alval]

Aluminium is soft and tends to stick and clog up the cutting edge along the tooth, the lubricant prevents this allowing a full depth chip cut each pass of the material. The blades you are using are good quality but 24 teeth per inch, it says it on the blade, they are more suited to thinner or harder material, if you had a coarser 18 teeth per inch blade you would cut through faster again taking more material each stroke.
Stuff that thick I use an angle grinder with a 1mm cut off blade and bees wax as lubricant, it is however very messy and a dust mask is a must, there is a technique to it, but a two inch bar only takes a minute or less.
Al

[Sunfish]

New blades are definitely the key . Sharper on the cutting edge and lubricant keeps them cooler and sharper.

A much coarser blade is quicker. A metal worker friend gave me a large bow hack saw with a very coarse blade to cut a 250x200x8mm flat plate and it did not take too long and was fairly straight. He uses windex. A little old school fun and less messy than the ss blade in a grinder or an aluminium blade in a drop saw.

You can finish on a belt sander or bench disc after filing flat.

[Sunfish]

The other kind of replacement knobs are chromed knurled guitar knobs. Solid brass with a set screw.

[LewisM]

If you'd let us know the knob shaft diameter, I am positive we could have found many alternatives. I regularly buy thumb screws, bolts, knobs etc from eBay or Alibaba.

Here's a start: https://www.ebay.com.au/sch/i.html?_from=R40&_trksid=p2057872.m570.l1313.TR11.TR C1.A0.H0.Xequipment+knobs.TRS0&_nkw=equipment+knobs&_sacat=0

[Symon]

Just stumbled upon this because of your mods this gentleman uses gt2 pulleys and belts I see them readily available on eBay
regards
Symon
https://youtu.be/im7DV2O4Eh8

[Ukastronomer]

Much more engineering though as compared, if you can find a knob then 70% of the work on mine is already done, you just need to do brackets.

[Ukastronomer]

Thank you

[Ukastronomer]

Thank you all, your advice has made it much easier, appreciated

[Exfso]

I know this might sound gross, but when I was an apprentice Electrical mechanic with Otis Elevators, we used to have a lot of metal conduit in the lift shafts then, and I found that one of the best lubricants for the dies cutting the conduit threads was simple spit when one ran out of cutting oil. :eyepop:

[Ukastronomer]

which is one thing that opticians say is the BEST thing to use on contact lenses if you are out and need to re insert them, hygienic as well from the body

[speach]

normal paraffin is the excepted cutting oil for aluminium