The mighty miter

So I’m to a point were I am ready to purchase some sort of mitering setup. Ideally I would buy a small knee mill but I’m not ready for that type of investment yet and they are hard to come by around here.

I have been looking at more compact mill drill type machines and also “Tube notchers”

So far I am leaning towards purchasing this:

Sync180Jr

Mostly because it seems to find the right balance between cost and rigidity. I would be using this with a hand drill for the time being while I build my first couple frames and decide if I want to invest in a mill.

My questions:

  • Does anyone have experience with this particular notcher?
  • Can anyone suggest a better setup that costs the same or less?
  • Can anyone share their experience using a smaller desktop style hobby mill or even a drill press for cutting miters?

Thanks!

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I’ve used something very similar in the past. It did cut pretty nicely. However the biggest problem is keeping the miters in phase with one another. It’s a problem that is probably pretty easy to solve though.

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First couple of frames? Straight up, just use mitre templates and a file. Its pretty quick once you have done a few plus the filing skills you learn doing it pay dividends when you move on to other areas of the bike. Look at it as a mini apprenticeship that builds a skill foundation.

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I’m not opposed to hand cutting, if I go that route I would 3d print the templates which would be fine for a bit. I’m just starting to TIG some practice joints and would rather spend the time on TIG than filing at the moment.

I went through the same thing not along ago. Didn’t want to spend time filing just for practice joints. I bought the cheapest notcher I could find to use for practice joints, knowing I would still be hand filing for actual frames.

I also did some exercises where I would use the notcher with a saw 1/8th too small and practice hand filing the rest of the way to get a perfect fit.

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Joint jiggers/tube notchers can work great (including that one) if:
-You’re mitering softer (no heat treated) tubing.
-You have a decent variable speed drill to run the saw.
-You have somewhere solid to mount the notcher.
-You are somewhat creative about improving the clamp. You can replace it entirely, you can sleeve the tube to spread the load, etc, etc. The stock clamps will either slip or damage the tube in most cases.

-Walt

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Why 3D print? Just use paper prints. Your hole saws aren’t going to cut for tapered head tubes and I’ll guarantee filing in will mess with you inless you are handy with it. :+1::blush: Takes about 5 mins to cut out the template, cut the tube and file it in once you are good at it.

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@BS_Industries I have that exact notcher. I’ll sell it to you for $200 + shipping.

With sharp hole saws, it works really well. Faster and more accurate than hand filing if you don’t have lots of hand filing muscle memory.

I bought it years ago to get away from hand filing, which I hated. It’s probably only mitered a few frame’s worth of tubes.

If you’re interested I can send a photo of it.

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@manzanitacycles Sold! That would be great, I’ll mesage you to arrange payment.

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Paper templates are so 2000! I don’t have anything against paper but i actually don’t have a paper printer. I do have two 3D printers that i need to justify so that is much more approachable for me.

I do still need to pick up some real files though, can you recommend any styles that are particularly useful for mitering?

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Lol. Fair enough. I use a mix of both templates and hole saws depending on what I need to do.

Just buy a quality brand, I’m loving my Bahco’s and Pferds, plus have a couple Nicholsons and some I don’t know what they are but have turned out to be quality. Get a mix. Bastards, mediums, fine. Flats, rounds, half rounds. I have about 50 files in the workshop and the majority of them get used. Chainsaw sharpening files are execellent for getting into tight spaces. Sharp half rounds make very short work of mitres.

Unless you have designed everything perfect and comes to you already cut and shaped before you stick it all together you are going to need to file just about every joint. Even if it’s just to clean the fluff off from hole saw cut.

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I copied this from The Bicycle Academy awhile back.

5" flat 2nd cut file with handle - with one safe edge this file is great for creating sharp lines and hard edges
6" half round bastard cut file with handle - great for creating the small mitres on a seat stay break bridge
8" half round bastard cut file with handle - a radius that closely matches a 25.4mm diameter tube
10" half round 2nd cut file with handle - a radius that closely matches a 28.6 or 31.8mm diameter tube
12" half round 2nd cut file with handle - a radius that closely matches a 35mm diameter tube
14" half round 2nd cut file with handle - a radius that closely matches a 46mm diameter headtube
16" half round bastard cut file with handle - a radius that closely matches a T47 bottom bracket

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I’m glad I am not the only one :rofl:

FYI, here is another thread about tube miter solutions: Anvil Tube Mitering Jig

I think a framebuilding-specific jigger would be a great addition to the frame builder toolset. A horizontal mill is going to be better, but realistically space is going to be harder and harder to find. When I have more time I will try to take on that project

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That’s a pretty good start. You end up with a big bunch of different ones and definitely get some needle and rifling files when you can.

I have had really good cuts with the hole saws @Carl_Snarl at metal guru carries.
Cuts a lot smoother than others I have tried

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I just bought a printer after not owning one my whole life. It’s a total game changer - best investment in tooling I’ve made this year, but don’t tell that to Joe at Cobra :wink:

I will agree with folks that the paper template + hacksaw + file process is surprisingly quick after you get the hang of it! If your mitering setup isn’t super dialed, it’s probably faster than futzing with a mill. And you can re-use them if you’re careful.

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To add to the simplification conversation- you really don’t need paper templates, especially for practice joints where you only have one miter on a tube. 8" bench grinders also work well for cutting miters- a practice joint on a thin-wall tube only takes a few minutes on a bench grinder.

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The problem with tube notchers is they vibrate a lot cutting thin wall tubes. For .035” tube 4130 it’s mostly fine. Once you get into the thinner diameters of like .9mm and thinner, there is more vibration. So, you need something rigid. There no comparison with a mill, either vertical or horizontal. The bigger, the more rigid. What happens sometimes when cutting thin diameter wall thickness tubes, is that the vibration leads to the hole saw tearing out a chunk of tube that totally messes up the miter. Bam! Wasted tube.

I had a nice tube notcher. They kinda suck, but they work even with thin tubes if you do some extra things. First, mount it horizontally on a stand or something that can bolt to the floor preferably. Second, run it at really super fast speeds. This is unconventional and goes against the normal operation of low speeds and even pressure if you were using a mill. However, I found that light pressure and high RPMs work better for tube notchers due to lack of rigidity on the notcher. Third, those things that are sold out there to add temporary wall thickness to a tube. What’s it called? I think it’s sold by the name of TWITS, thin wall tube supports. Those things work really really well. You could probably make your own or do a google search and buy what’s out there.

…or instead of tube notchers, or in addition to them, the advice with files is spot on. You’re going to need some anyway just to clean up the burrs that the hole saw notcher leaves.

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Great suggestion, I’ve never heard of TWITS, what a great name :rofl:


image

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Wow! You guys don’t even own a paper printer?! How would you even print a CAD drawing, even just a miniature one?

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