Can I ask where do you get your FINETOOTH hole saws in Europe?
I’ve had good success with these ones: Spezial M42 Bi- Cobalt Vario 8/12 Lochsäge
They come in most sizes, have the same thread as the starrett ones (although it says otherwise in the data sheet) and they’re reasonably priced. Tooth pitch varies between 8 and 12 teeth per Inch
I am using these: https://mandrex-system.com/product/finexcut-m42/https://mandrex-system.com/product/finexcut-m42/ Available through a lot of webshops over here.
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The Coba-Tech fine tooth saws from Stakesys in the UK are good.
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Actually I Just came across this problem. I also have eu made bsa BBs. And there is a solution: starret makes this one in 39mm. You just need to get rid of the rim.
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Sorry, it’s time for me to bail on the forum.
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Thats what I would think if I did not test it. It actually cuts pretty good (and much better than I’d expect). I’ve tried higher rpms ~600 to 930. This tube in the pic is 0,8mm (just scrap beeing test cut so it’s not even centered).
I guess the thing is - a wholesaw of this tpi would probably rip the tube apart. But: this is not a wholesaw. The difference is that a wholesaw is never round, so it needs to be high tpi not to catch material. This one has teeth that are brazed and than sharpened so each of them follows the same circle thus greatly reducing risk of cathing. They are like lathe knives.
Only problem is that this things’ thread is just a bit different and it does not fit paragon arbours.
Edit: one more thing. For those who are concerned about heat and might want to research this further: when using regular wholesaws oil is burning. Here - no smoke at all, so my guess is there is less heat. Just cut this one:
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Sounds all good.
Would be an other solution to skim off 1mm of the bb. To 38mm?
Sorry, it’s time for me to bail on the forum.
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Interesting! This cutter might be working like a coldsaw:
Cold sawing uses a circular blade to remove material while transferring the generated heat to the chips that are created by the saw blade. A cold saw utilizes either a solid high-speed steel (HSS) or tungsten carbide-tipped (TCT) blade turning at low RPMs.
I am glad it works, it looks like a really nice solution. Was this the one you got?
Is that without coolant?
More less this one. Now I’ve figured out that there is one version for deeper cutting (I got the shallow one of course and had to cut in 2 go’s…).
@Smoothsailor If I had a lathe - probably yes. But this way I have a thicker bb and I find it better for welding.
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I use these hole saws: https://www.ultratools.fr/Fine-pitch.php Fine pitch (10 tpi) in imperial sizes. Downside: they are shipped from the factory in India, so much additional costs. But make very nice and fitting cuts. Bimetall-Lochsägen HSSE-Co 8 mit Feinverzahnung 126057 | Lochsägen makes fine pitch holesaws, too.
For my 39 mm bbs I use a core drill, but it is a mess. I ruined some tubes by too much feed, now I go real slow. Real slow means real slow: almost fifteen minutes, but I get a perfect cut …
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ATI41323 they look nice and not super expensive…
farr make arbors for ati hole saws that look slick
Would grinding down one of these work they are not 300 bucks ?? I just came across this problem with a Bike fab supply intergraded BMX head tube.
115MM LENGTH - 39MM OD HEAD TUBE BMX SHORT TAPER IS42/42 -4130 — BICYCLE FABRICATION SUPPLY .
to make it work at the moment I hit it with a file and wrapped a bit of sand paper around head tube in question and sanded it through… its not perfect Instagram photo quality but ok…
just when you think you have all the stuff to make stuff you need to buy more or make more stuff for making stuff…
I’ve gone the other way around after this enlighting topic. Either I use 40mm shells or I turn down the center of a 39mm shell to 38mm. Works great and looks nice too.
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