lejo

So, i have built a setup for my lathe. Waiting for my tubes from Reynolds. The Headtube is 46.5mm OD and BB should be 38mm OD. The top and bottom tube are 28.6mm OD. What kind of saws are you guys using for nothing. The 38mm is ok and easy to get but 46.5 not. The closest i get is 46mm or 48mm. Guess 46 is the best choice and then file the rest…?

unterhausen

A holesaw will cut a little large unless you do something about it. But I would expect to file a little anyway. Most people face the mounting surface of the saw. If you leave it, it will wobble more

I had a lot of trouble with my lathe doing this and gave up and went back to hacksaws and files. But then I figured out what was wrong with my lathe and fixed it. So maybe I'll try again.

lejo

Thanks and of course you are correct. So 46mm will do. The lathe seems ok for now but i will certainly look into the surface. It is not wobbling much now. Just a little.

Doug Fattic 

A couple of tips using hole saws to miter tubes. 1st they work better if you get the Paragon hole saw holders. The ones that are supplied are a bit flimsy. Unterhausen already mentioned to face the mounting surface of the hole saw. My second tip to get a perfect size is to use 2 hole saws. The 1st one would be the 46 to hog away most of the material. The 2nd hole saw you squeeze the teeth of another 46 a little to make it a bit more oval. This is by trial and error. Of course now the hole saw is cutting on only 2 or 3 teeth instead of more but it works great to get a perfect size that is slightly larger. They won't be cutting too much if you have 1st cleared away most of the miter with a slightly smaller hole saw.

All hole saws are not the same. The best ones have more teeth. Someone else will have to tell you where they can be bought. I don't remember now. With my setup I can always get great miters without ever having to use a file for correction.

lejo

Thank you. Good tip. I’ll check this out.

lejo

One more thing. Do you use saws with hard metall teath or bimetall?

mikeread

If you have a lathe it is dead easy to make your own drum sanders to exactly the right diameter (allow for the thickness of your abrasive)

Rough out the miter with a hacksaw and file and then finish up on the drum. As long as you clamp the tube well you get a perfect miter very easily.

I put the drum in the lathe chuck and clamp the tube to the toolpost.

It wouldn't be much good for a production environment as you have to change the abrasive a few times but for a one off or occasional frame it works a treat.

lejo

Thank you. That is a new idea/consept for me. I’ll think about that.

Andrew R Stewart 

I have an abrasive mitering set up that I don't use. Anyone interested?

It's all fine and dandy to seek hole saw mitering (and I agree with the advise given) but some minor touch up filing is often needed. To fine tune the angle of miter diameter as common reasons. I generally cut (on a mill with hole saws) my tubes a couple of mms long and fine tune to fit. This actually takes as long or longer then a hand miter. I used my bench grinder to rough out miters ,followed by file tuning, for years. But having big tools means one can use big tools

Missouri Precision Tools, Inc.: Rockhard HSS BiMetal Fine Tooth Hole Saws (mo2ls.com)

Mist Tools (mist-tools.com)

These are two sources for fine toothed hole saws. Andy

mikeread

If you go the sanding drum route - make them longer than I did if you can. More abrasive = fewer changes

unterhausen

If you use sanding drums on a lathe, my recommendation is to get a big sheet of rubber to catch all the dust and protect the ways. And don't use air to clean off the ways afterwards, use a vacuum.

lejo

Thanks but i think i will stick to hole saw for now at least. Just ordered a couple of saws. Mandrex superXcut that i hope will do the trick. I’ll also make a custom anchor for these to my lathe.

JohnDThompson 

Mike Appel used a similar arrangement with a bench mounted belt sander, several appropriately sized drums, and a cross-slide machinist's vise to feed the tube into the drum.

duanedr 

The superXcut shown below (Orange) isn't what you want. It looks like Mandrex has a 'FineXCut' M42 shown below (white) that should work. It's hard to tell how they attach to the arbor. It is better if they are welded to a thick plug that is threaded for the arbor rather than those held onto the arbor by a nut from the inside. Either way, you have to face the saw where it interfaces with the arbor. Then trim off any teeth that are weird shaped or might snag. You can do that with a file or even just run them up against a belt sander real quick. These wayward teeth leave grooves when retracting the tool from the cut. Doug has a great tip and I'll definitely try that one!

The fine pitch (10t/inch) ones from Missouri Tool that Andrew linked to are quite accurate and durable. They also have a nice thick arbor mounting plate for added rigidity. I recently got an ATI in 1-1/8" and I'm really impressed other than the arbor threads are pretty small for the saw diameter and the saw isn't very deep.

lejo

Thanks again. Yes, i had a look at the Missouri tool and that looks quite good. Doesn’t seem like they have any dealers in Europe, UK or Noeway though. I might still order one but would be expensive with shipping and tax to Norway.

lejo

Thinking about the sanding method some more. I might try that. I guess the round bars needs to be the OD of: Headtube, BB, seat tube including paper. What size of the square bar is suitable? My tubes are 28.6mm mostly. One is 31.something. Would 40x40mm profile be enough?

unterhausen

When I bought saws from Missouri tool, they were made in Spain. I think I would just get a high quality fine tooth bimetal hole saw. Does Bahco make them?

duanedr 

My Norwegian is pretty poor - even worse than my Finnish - so I was looking only at UK sites (some say my English is pretty poor as well but I manage).

These look like possible options. It looks like there's good thickness that the arbor threads into.
Coba-Tech 8-12 TPI Fine Tooth Holesaws (stakesys.co.uk)


These are a step up in price and probably accuracy. They have a 46mm one as well.
Fine & Course Tooth Hole Saws - AET (aetools.co.uk)

unterhausen

The AET ones look nice. It seems like there is another name for that kind of hole saw, which has conveniently slipped my mind.

dsaul

Those are similar to an annular cutter, except they don't have chip clearing flutes on the sides. They work better in thicker walled tubing. They tend to catch and tear thin walled bike tubing.

unterhausen

Thanks, I was tryin' to think, but nothing happened.

duanedr 

These are different from annular cutters. I tried one of those and they don't work well for cutting thin walled tubing - .maybe for thick walled tubing of like 0.125" walled....

The AET look very similar to the ATI ones that are available here in the US
ATI413 SERIES, FINE TOOTH (atitoolstore.com)

They work really well but, they seem to err on the side of too small threaded arbor hole for the bigger saw diameters. I'd like anything above a 1" cutter to have 1/2-20 threading. Peter Farr sells arbors for these similar to the Paragon ones but with ATI threading. The ATI are very similar to the ones Torch and File sell other than depth it seems. The T&F ones are longer (I ended up with a couple from a bulk purchase) so they cut through a full tube. The ATI ones require you to cut the tube pretty close to the length as measured at the ends of the ears or clear them out half way through the tube with plyers. The ATI ones leave a really nice cut edge that I rarely get with the others though. 6 of this, half dozen of that.... Also, the ATI style has wider (thicker?) teeth so requires more rigidity in the arbor, machine and work holding otherwise it chatters a bit.

unterhausen

David was just addressing my comment about another name for thick walled hole saws. Annular cutter was what I was trying to think of without success

Those ATI look like they have fewer teeth than the AET saws. I thought AET was available here from somewhere, but the mounting hole would be a problem.

"Thick wall hole saw" isn't a good search term for some reason. And "heavy-duty hole saw" just gets you plain old hole saws, because of marketing puffery.

duanedr 

I just wanted to make sure no one got the idea that annular cutters were a viable solution. In my attempts they weren't.

I wish someone would come up with a variable diameter hole saw that changes diameter as you're mitering for tapered headtubes!

unterhausen

The sanding mandrels pictured in this thread made me wonder about a tapered one for tapered headtubes. Might have to go to little strips of sandpaper. Or glue