Framebuilders - Cutting miters in cro-mo/mang-mo with a hole saw?

I'm building my first frame, and as I was laboriously hand cutting and hand filing my top tube miters, I remember seeing pictures of someone using a bimetal hole saw to cut miters in steel tubing.

How many of you do this? What brand of hole saw do you use...I assume the Milwaukee hole saw I got to cut holes in plywood wouldn't be sufficient? Can a decent drill press be used to cut these miters, or do I need something more along the lines of a milling machine? Any other advice, or limitations on what type of tubing I could cut using this method? I'd assume that cro-mo would be fine, heat treated cro-mo would be tough but do-able, and super tough stuff like Reynolds 953 (which I am in no way even thinking about using) would be a no-go.

Thanks!

Pete

You can cut stainless with a holesaw: http://www.flickr.com/photos/couragebicycles/4178214876/

http://farm3.static.flickr.com/2735/4178214876_ed2942a9a7.jpg

Yes, I realize SS can be cut with a hole saw, but I'm wondering what can be done with a reasonable amount of equipment (for example, a good drill press).

Miter by hand until you can afford a Bridgeport. Setting up a press and the necessary vices you will need to cut the tubes are not worth it. Also you'll need to have a machine shop build you a jig to hold the tubing at the desired angles. :eek:

Well, I don't see a Bridgeport in my future, as I think the most I could justify spending (without my wife killing me, and this would be only after I've built a number of frames) is about $2k for the mill. Grizzly (http://www.grizzly.com/products/mach-specs.aspx?key=480000) has a number of them at around that price. Moreover, my workshop is in my basement, I have a walk-out, but I think the most I'd be able to manhandle in there (via beer and pizza fueled friends) is about 750 pounds. I'm sure a Bridgeport weighs more than that.

Pete

Something like this?

Harbor Freight tubing notcher - $49.99 (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=42324)

Harbor Freight tools are hit or miss, but for $50, it'd be worth a shot to see if it actually worked. I've always avoided their power tools ever since a guy at work bought a bench grinder from there, and the wheel would stop anytime you put a piece of metal against it.

Harbor Freight tools are hit or miss, but for $50, it'd be worth a shot to see if it actually worked. I've always avoided their power tools ever since a guy at work bought a bench grinder from there, and the wheel would stop anytime you put a piece of metal against it.

I hear you. I figured this is a pretty safe bet because: A) it's not a lot of money, and B) it doesn't have a motor; the motor is your electric drill. I ordered one after last week's framebuilding class at Tim Sanner's, so when it gets here I'll offer an opinion on the quality.

I ordered one after last week's framebuilding class at Tim Sanner's, so when it gets here I'll offer an opinion on the quality.

Thanks, that'd be really helpful.

mudboy.. yeah i feel your pain. I'm below ground as well. I had to pay two piano movers 100 bones to get my surface plate in.. my next purchase is shop space with a roll up door on ground level.

You should be able to find a mill, particularly horizontal for as little as 200 to 600 on Craigs, or Kijiji. Just keep looking. Griz stuff will work, but is more expensive, less quality, lower resale. Check lathes.co.uk to find out about models.

people do use regular hole saws, but the fine tooth saws are better. Starrett apparently makes some. I got mine from here (http://mo2ls.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=mpt&Category_Code=SCF), haven't set up my lathe to cut miters yet. Seems like those are the most popular hole saws on the frame mailing list. I got Paragon mandrels.

Years ago when I tried a regular hole saw in a drill press, the cutting forces pulled the chuck right off. You could probably mod one of the cheap Chinese tube notchers to use a better mandrel.

http://www.aircraftspruce.com/menus/to/tubing_notchers.html

http://www.aircraftspruce.com/catalog/graphics/12-30000.jpg

http://www.aircraftspruce.com/catalog/graphics/12-01107.jpg

http://www.aircraftspruce.com/catalog/graphics/12-01108.jpg

PaPa, I like the looks of that first one, as it would work well (mounted horizontally and using a 1/2" corded drill) with the tool mounting system I built for my workbench. Do you have any experience with that particular model?

Thanks,

Pete

Do you have any experience with that particular model?Pete,

No. Bare-in-mind, however, where the linked hole saws shown above are sold... from the same supplier offering 4130 chromoly tubing. I use either a cut-off saw or my 66 year-old South Bend lathe w/hole saws... depending on how fussy I am. Contrary to popular belief, I would never use a drill press - I've heard too many horror stories and know first hand, just how damaging it is to arbor bearings.

PaPa, I like the looks of that first one, as it would work well (mounted horizontally and using a 1/2" corded drill) with the tool mounting system I built for my workbench. Do you have any experience with that particular model?

Thanks,

Pete
I use it for bamboo. It does a fair job.

http://www.youtube.com/watch?v=TMA8X5pk2kI

Look around the 1 minute mark for how long it takes to hand miter a tube. If the miters are deeper use snips first.

"I've heard too many horror stories and know first hand, just how damaging it is to arbor bearings."

That's an OWT, lots of people use drill presses as mills without affecting the bearings. Even if it did, drill presses are cheaper that hand drills these days, so who cares. The real issue with drill presses is that they make bad mills, so why bother. That said the use of hole saws is drilling not milling so they wouldn't have a problem with that.

I wouldn't bother with the notchers. They have neither the versatility or accuracy of the mill, while keeping the slow set-up time. The aircraft biz is somewhat like the bike biz, but moreso. You get the weekend warriors who use a mill to cut tubes, and then you have the pros who use aircraft snips freehand...

here is another hand mitering video:

http://www.youtube.com/watch?v=KIxCdTRkRHo

I've been practicing mitring by hand, and with a rough cut (with the hacksaw) close enough to the scribe line and the proper size half-round file, it really does not take much time! Before investing in vert. or horiz. mills, I'd practice a bit more by hand. From what I hear a notcher + drill press is a false economy.

That's an OWT, lots of people use drill presses as mills without affecting the bearings. Even if it did, drill presses are cheaper that hand drills these days, so who cares. The real issue with drill presses is that they make bad mills, so why bother. That said the use of hole saws is drilling not milling so they wouldn't have a problem with that.In your dreams PP. Drill presses are NOT designed or built to tolerate high side loading - which is exactly what you impose on the arbor bearings when you take off-axis, single-sided cuts off the ends of tubes. Further, the lack of torsional rigidity between the headstock and the table promotes chatter and sudden lockups - often ripping the holder from the table or destroying a $15 stick of chromoly... or worse yet, dissecting a finger. I'm reminded of the bozo touting O/A gages are useless.

Contrary to popular belief, I would never use a drill press - I've heard too many horror stories and know first hand, just how damaging it is to arbor bearings.

Ive never used one, but it looks like the notching fixture being discussed has a shaft that transmits the torque from the drill arbor to the holesaw. The shaft is located in a sleeve of the fixture which should isolate most all of the side load from the drill press arbor bearings. No?

Ive never used one, but it looks like the notching fixture being discussed has a shaft that transmits the torque from the drill arbor to the holesaw. The shaft is located in a sleeve of the fixture which should isolate most all of the side load from the drill press arbor bearings. No?

Exactly. The notchers all have fairly long sleeves (most with a bushing) that should minimize side loading the hand drill or drill press bearings.

"In your dreams PP. Drill presses are NOT designed or built to tolerate high side loading - which is exactly what you impose on the arbor bearings when you take off-axis, single-sided cuts off the ends of tubes."

The machine isn't built to take those loads, but your ill informed if you think lots of people aren't doing it, or there aren't DVDs from well known machinists, on how to convert a drill to do it. I don't do it, I own two mills. I never did it in my past when all I had was a drill press, except for guitar bridges.

For that mater they sell drum sanders that mount in drill presses, they sell planer blades that mount in drill presses, they sell grinding stones. People drill uneven surfaces. Use reamers, use taps in the DP. These are all axial load tools. You don't know what you are talking about.

As far as tubing is concerned the main loads are in line with the quill when drilling a tube The axial loads are trivial.

Ive never used one, but it looks like the notching fixture being discussed has a shaft that transmits the torque from the drill arbor to the holesaw. The shaft is located in a sleeve of the fixture which should isolate most all of the side load from the drill press arbor bearings. No?Correct.

The notchers shown above have a shorter load path distance between the tubing fixture and the arbor - perhaps 6" or less and is usually heavy gage material. This prevents unwanted movement between the hole saw and the tubing - which in turn, prevents chattering and lockups due to torsional misalignment. The 'load path' distance on an 15" drill press is closer to 36", often more. While using the notcher (when mounted to the drill press table) still induces torsional loads on the drill press, the side-loading (or radial loads) is absorbed by the rigid notcher, and not by the drill press.

"The shaft is located in a sleeve of the fixture which should isolate most all of the side load from the drill press arbor bearings. No?"

It would be relatively easy to isolate those loads if you wanted to with a drill press. One could mount a bearing or two on something and take the load off the quill or shank to the column or the wall,etc... It would also be possible to mount the hole saw on a spindle that took the load off to the table, though that would limit the depth of cut. Not necessary really, but possible.

By the way, just to dispel a little of the panic on side loads here are two videos on milling in a drill press. Waste of time in a a KIjiji/craigs world with virtually free milling machines in every dumpster...

http://smartflix.com/store/video/90/Milling-on-the-Drill-Press

http://smartflix.com/store/video/43/Drilling-Tapping-and-Milling-on-the-Drill-Press

Waste of time in a a KIjiji/craigs world with virtually free milling machines in every dumpster...


You must have the same C.L. where the vintage guys keep finding top shape Japanese beauties for peanuts. I`ve seen a few machines on my C.L. that looked relatively cheap to me, but always 3-phase.

of course they are 3 phase. I shouldn't tell you this, but that really shouldn't stop you. It takes a day or two to learn enough to make a 3 phase work.

I haven't taken too many of the free ones, I generally have paid fairly high prices because I don't mind paying the same for old iron as new Chinese would cost, and usually it isn't even that expensive. I like smaller machines for the most part, and finding mint ones is worth the wait and money. Something I learned after buying others first. Soon I had bought so many I was virtually in the business (at least, I guess, in the minds of others). I started to get insane offers just for moving stuff out. I took up a few and then sold them, but I had to shut it down before it got out of hand because I already had a 24 foot boat taking up all the space in my shop.

I think the deals stories are like that. You have to blow your brains out first to get established. I vaguely know this guy who collects anvils. he has so many he has an anvil pasture with hunks just sitting out in the weather, as well as his inside the barn collection. I suspect he got started by sinking way too much in, now he is averaging down. He doesn't sell them, they are his "IRA". Every time he goes out antiquing he picks up more. For myself I can't find one (except the Peter Wright someone gave me so don't feel too bad) for less than 3x what they are worth, and that is before showing up and finding they have cracks...:lol:

There may be a simpler how to, but:

http://www.practicalmachinist.com/vb/forumdisplay.php/transformers-phase-converters-and-11.html?f=11

http://www.practicalmachinist.com/vb/showthread.php/rotary-phase-converter-designs-101231.html

http://www.youtube.com/results?search_query=phase+converters&search_type=&aq=f

Something like this?

Harbor Freight tubing notcher - $49.99 (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=42324)


Harbor Freight tools are hit or miss, but for $50, it'd be worth a shot to see if it actually worked. I've always avoided their power tools ever since a guy at work bought a bench grinder from there, and the wheel would stop anytime you put a piece of metal against it.


I hear you. I figured this is a pretty safe bet because: A) it's not a lot of money, and B) it doesn't have a motor; the motor is your electric drill. I ordered one after last week's framebuilding class at Tim Sanner's, so when it gets here I'll offer an opinion on the quality.


Thanks, that'd be really helpful.

Well, it arrived about a week ago and the fine tooth hole saws recommended by unterhausen arrived today, so I tried it out. I'm pretty happy with the results. All it took was a little filing to get a perfect 73° miter.

http://i32.photobucket.com/albums/d7/k4drd/Bicycles/Frame%20Tube%20Joining/CIMG6254sm.jpg

http://i32.photobucket.com/albums/d7/k4drd/Bicycles/Frame%20Tube%20Joining/CIMG6255sm.jpg

http://i32.photobucket.com/albums/d7/k4drd/Bicycles/Frame%20Tube%20Joining/CIMG6256sm.jpg

Cool. Did you need to file because the angle was a little off, because the cut was a little rough, or both?

Cool. Did you need to file because the angle was a little off, because the cut was a little rough, or both?

The angle was dead on, but the cut was rough, particularly the very last bit on the back side. I spent about two minutes with a half-round cleaning it up.

Thanks, Scooper. Looks like I'll make the trip to my local Harbor Freight this weekend...I needed some new one-handed wood clamps anyway.

Another frequently used tool in my shop is one of these:

http://www.wixey.com/anglegauge/index.html

I see Harbor Freight has one now too, but I'm not particularly fond of Cen-Tech stuff.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95998&xcamp=google&utm_source=googlebase&utm_medium=cpc&zmam=33951326&zmas=12&zmac=112&zmap=95998

Here's a photo of the 28.6 mm top tube mitered to the 31.7 mm head tube.

http://i32.photobucket.com/albums/d7/k4drd/Bicycles/Frame%20Tube%20Joining/CIMG6266sm.jpg

Big gaps dude, the miter is too narrow at the "ears".

Big gaps dude, the miter is too narrow at the "ears".Which usually indicates the hole saw was slightly too small in diameter. You can touch'em up with a file, or try different hole saws.

Which usually indicates the hole saw was slightly too small in diameter. You can touch'em up with a file, or try different hole saws.

Dumbest question ever, but you would use a 1 1/8" hole saw when mitering to a 1 1/8" tube, 1 1/4" hole saw when mitering to a 1 1/4" tube, etc., correct? A set of 3 saws, 1 1/8", 1 1/4", and 1 3/8" should cover me for most oversized steel frames with 1" headsets, right?

Thanks

Pete

One uses the hole saw of the size of the tube one is joining to, not the size of the tube being cut. I just compare the saw to the tube itself, remember that it will cut to the outermost set of the teeth, the largest possible radius. Saws can be trued with a grinder on a lathe or a cutter sharpener. one can adjust the fit on the tube by slightly ovalizing it. pinch it across and it will fit tighter, pinch it in the vertical, and it will be wider. This can be better since the length of the tube will not be affected as much as might well occur with a heavy fitting, of course a light touch should work also.

Yeah. The hole saw was 1 1/4" (31.7 mm) so the 28.6 mm top tube would fit snugly against the 31.7 mm head tube.

Yeah. The hole saw was 1 1/4" (31.7 mm) so the 28.6 mm top tube would fit snugly against the 31.7 mm head tube.Not all saws are equal and most are cheaply made - since most are open packaged, pack a caliper and measure individual saws prior to purchase. I've seen as much as .040" variance in the same labeled size. Remember, these are NOT precision tools.

Scooper,

Is that stainless tubing you're working with?

Scooper,

Is that stainless tubing you're working with?

Nope; it's Nova seamless double-butted 4130.