Tapered reamer for coring?
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Cody Cash
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Actually i was at bob's and have seen this first hand. There are several advantages such as tighter tollerances more glue options larger wall thickness of the core wood at the A joint (if you drill your hole into the forearm). I am still on the fence though if the benefits outway the extra work and tooling costs. I don't know if any of the small cue lathes could handle the task. Bob says it's pretty rough on his enco.
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That settles that.
No metal lathe, no go for some.
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The ability to use TiteBond wood glue is enough benefit to justify it to me. As for power, I'd think a proper pilot hole would eliminate any load stress on the machine. I cannot imagine any scenario where machining wood could bog down a machine lathe, unless the cutter is ridiculously dull.
I used to hear the same stuff about coring with gun drills.
Cody Cash
Registered
He is gundrilling all the way with .625 then partway with .75 then reaming. I don't think it's a power problem i think its a chatter problem. Over 13 inches hanging from the tailstock and removing a lot of wood where reamers are designed to remove small amounts of material
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Can't grab the drill and use hand as steady rest on this drill.
Sucker's gonna be tough.
Ah gotcha. That makes more sense than being power starved. In that case, chucking the back end of the blank while supporting the front with a bearing rest should go a long way in alleviating chatter.
Food for thought, but I see a potential flaw. It's tough to tell from the pic, but the relief angle on that reamer looks more conducive to metal cutting than it does wood. The relief angle for woodworking cutters is generally a lot steeper, allowing the edge to aggressively dig in and peel wood away. Metal cutter reliefs have less degree pitch. By comparison, metal cutters scrape where wood cutters peel. This could very well be the root of the chatter issue.
I have a sawmill. When I am cutting softer woods such as pine or cedar, I get the best cuts using a blade with 10* relief angle. For woods like maple I use 7*. For osage or dry white oak, 4* cuts best. Using 10* blades on an osage log won't work well because the teeth dig in and grab too aggressively, which not only causes the engine to bog but also very quickly dulls the blade. On the flip, using a 4* blade on pine is slow, clogs up the gullet with fine powder dust, and the resulting heat causes the blade to lose its set. Having the correct relief angle for the material being cut is critical in getting a clean, smooth cut and long blade life. This is nuts & bolts basic knowledge with saw milling, but not so much for cue making. A whole lot of the tooling we use is re-purposed machine tools & bits, and as such has a default grind for cutting metals. I regrind everything for a relief more suitable for wood. I wonder how many other builders do the same, or how many are either unaware of the difference or unaware of how significant the difference is. Having a custom cutter made by a shop who specializes in tool/die making would more than likely result in a tool that is ground for machining metal, not wood. You'd have to specify the relief you want or else trust that the machinist understands woodworking & will give it the proper relief. Otherwise you have a woodworking tool designed for metal.
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JC
Coos Cues
This consideration and others is why I'm thinking in terms of the smallest possible taper to achieve the goal of not wiping the glue away. The less wood to remove and least stress on the wood and equipment. I made some short mock ups with a boring bar and glued them up and decided that .030 over 14 inches is enough. you are only enlarging the big end .015 per side. I asked the fellow at the reamer company if he thought it would work and he told me he knows it will because he's already made "very similar" reamers for cue makers with no complaints. He also said they last "forever" in wood. His words not mine. Which gave me some comfort.
Here's a cross section photo of one I glued up with west systems and that particular taper. It slid together and locked with just a little twist spitting excess glue out of both ends.
I've decided to go ahead and try this. My order is in engineering but I can change the quantity still or tweak the dimensions if there's a compelling reason.
If anyone wants to try one here's what I'm having made.
Total length 16 inches. 14 inches of reamer. HSS 3 flute, right hand flutes, not air cooled. I figure if I need to I can blow air in the far end while reaming since it's not a blind hole. 1/2 inch shank, two inches long. Small end of reamer .647" Large end .677"
PM me if you want one. No guarantees, you know as much as I do about it.
8 weeks production time. Need to know by next week so I can order the correct quantity.
If on the other hand you would like to mock me and tell me how ignorant I am, I can take that too. No biggie
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Whenever you have asinine idiots that spout this ^ ^ ^ ^ nonsense, it's bound to happen.
My initial thoughts on the subject were based on your factual mock up.
Meaning basically....I don't believe the inner core taper needs to parallel the outer OD taper to become an effective construction technique.
Maybe one day I'll dive in to actual testing also.
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I think you are forgetting something. A drill is cutting only at the end a tapered reamer is cutting along the entire length of the reamer. In our case that is over 12", that means you have a huge surface engaged with the cutter. So yes having a rigid and strong machine is the way to go. In your example the long tapered reamer is taking a much larger cut than your 3/4" drill.
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JC
Coos Cues
You can have them made in any dimensions you desire.
Can you elaborate on why 7* would be ideal?
Never mind I didn't see your previous post. Duh!
Thanks,
JC
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This can also be a detrimental factor, when I first started fooling around with tapered cores I cracked a few just from the hydraulic pressure when gluing in the core. If you have a reamer with to aggressive tool geometry you will be splitting forearms like crazy because the reamer is going to want to self feed into the piece.
JC
Coos Cues
A machinist with much more experience than I suggested that if cutting became an issue at the large end you could always bore some out down there first as far as you can comfortably reach with your bar to ease the stress and minimize the contact until approaching the finished surface and even turn it around and take some out of the small end. Hoping not to have to do that but there is comfort in a plan "B"
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JC
Coos Cues
The Reamer
Finally received this thing. It actually works better than I could have hoped. With the small taper it cuts the hole fast without too much heat on moderately hard wood. On softer wood it cuts like butter. Took about a minute to ream the Pau Ferro in the video. I put a vacuum at the bore outlet at the left end of the head stock to draw air to cool and clear the flutes of dust.
No dry spots going to happen here. Can let the west systems soak in for a while first. Or even use titebond I guess. I plan to put the "A" joint at the small end to lock things in so to speak. We'll see how long it stays sharp.
Finally received this thing. It actually works better than I could have hoped. With the small taper it cuts the hole fast without too much heat on moderately hard wood. On softer wood it cuts like butter. Took about a minute to ream the Pau Ferro in the video. I put a vacuum at the bore outlet at the left end of the head stock to draw air to cool and clear the flutes of dust.
No dry spots going to happen here. Can let the west systems soak in for a while first. Or even use titebond I guess. I plan to put the "A" joint at the small end to lock things in so to speak. We'll see how long it stays sharp.
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