OldTools Archive
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276628 | Darrell <larchmont479@g...> | 2022‑11‑26 | knockdown shelf project continues to entertain me |
Galoots, I stopped to take a few pictures of my Work In Progress. It isn't my design, and isn't what I would build for myself, but it is what my friend wanted. I tried to load the photos on the groups.io site, but when one tries to acquire a link to the individual pictures you get really strange looking URLs. So I just included the link to my album. You'll have to dig up the pictures and try and match them to my words. Here you go... https://groups.io/g/oldtools/album?id=267353 I decided to use a 10 degree wedge for the tusk tenons. that seems to be small enough to stick and large enough to unstick without having to hammer the heck out of it. I've made this kind of thing before, so I rummaged around for the 10 degree paring block I recall having made. There it was, along with the sample wedges. 10, 11, and 12 degree wedge blanks, but only the 10 degree paring block. 'Cause that's what I ended up using last time. I dunno why, intuition or inspiration, but something moved me to stick the wedge against the block and slide a square up against them. Not square. Out came the protractor. The wedge is a neat 10 degrees, but the paring block was 12. Despite having "10" literally written all over it. Should I switch to 12 or start a fight with the tools to fix this thing? I could hear you all out there chanting 'fight! fight! fight!', so I pulled out some really precise tools and set about adjusting the paring block to match the numbers on it. That end grain red oak is tough but it behaves quite nicely, so I soon had an actual 10 degree paring block. yay. So. What was I doing? Right, wedge mortises. I set a double square to make the layout easy and proceeded to make a sample out of an offcut. I used a very nice #8 auger bit to clear the bulk of the waste from the mortise, then pared it square. The paring block was clamped on to guide the final cut. The sample was really good, so I proceeded to botch the cutting of the first real mortise. Luckily, the wedges I made up (neanderbuddy work, not shown here) are big enough to do the job even on the mis-cut mortise. Once I figured out which way was UP, the layout and cutting of the rest of the mortises was quick and easy. The shelf unit is mostly done now, apart for some finish. That will probably be orange shellac. Darrell uh oh, now I have to start on that lying press. -- Oakville ON Wood Hoarder, Blade Sharpener, and Occasional Tool User |
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276629 | Chuck Taylor | 2022‑11‑27 | Re: knockdown shelf project continues to entertain me |
Darrell asks about wedge angles: ==== I decided to use a 10 degree wedge for the tusk tenons. that seems to be small enough to stick and large enough to unstick without having to hammer the heck out of it. ==== Degrees work pretty well in math class, but for woodworking I have found that "rise and run" ratios are easier to use. For Krenov-style plane wedges I was taught to use a ratio of 1:10, which works well for me. YMMV. Here are some ratios that cover a reasonable range for wedges and their equivalents in degrees: 1:4 is about 14 degrees 1:5 is about 11.3 degrees 1:6 is about 9.5 degrees 1.7 is about 8.1 degrees 1:8 is about 7.1 degrees 1:9 is about 6.3 degrees 1:10 is about 5.7 degrees 1:11 is about 5.2 degrees 1:12 is about 4.4 degrees I find that ratios are easier to mark out and reproduce consistently. YMMV. Cheers, Chuck Taylor north of Seattle USA |
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276633 | Darrell <larchmont479@g...> | 2022‑11‑27 | Re: knockdown shelf project continues to entertain me |
On Sat., Nov. 26, 2022, 8:36 p.m. Chuck Taylor, |
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276644 | gtgrouch@r... | 2022‑12‑01 | Re: knockdown shelf project continues to entertain me |
If you need this information and have access to a calculator with trig functions, you can use the arc tangent to get this angle. This varies according to the calculator, but you enter the number, then press the 1/X function key, then (usually) you press the INV key followed by the TAN key. So, on my calculator, the ratio of 1:9 gives me 6.3401917459099093959941376648275 degrees. Not that the fraction matters. YMMV. Void where prohibited by natural law or the imprecision inherent in a pencil line. Gary Katsanis Albion New York, USA with thanks to Chuck Taylor for suggesting this eminently practical approach -----------------------------------------From: "Darrell" To: "Chuck Taylor" Cc: "oldtools@g..." Sent: Sunday November 27 2022 5:56:15PM Subject: Re: [oldtools] knockdown shelf project continues to entertain me On Sat., Nov. 26, 2022, 8:36 p.m. Chuck Taylor, wrote: > Darrell asks about wedge angles: > > > Here are some ratios that cover a reasonable range for wedges and their > equivalents in degrees: > > 1:4 is about 14 degrees > 1:5 is about 11.3 degrees > 1:6 is about 9.5 degrees > 1.7 is about 8.1 degrees > 1:8 is about 7.1 degrees > 1:9 is about 6.3 degrees > 1:10 is about 5.7 degrees > 1:11 is about 5.2 degrees > 1:12 is about 4.4 degrees > > I find that ratios are easier to mark out and reproduce consistently. YMMV. > > Cheers, > Chuck Taylor > north of Seattle USA > Thanks Chuck I'm going to print this out and stick it on the shop wall -- wood hoarder, blade sharpener, and occasional tool user > Links: ------ [1] https://groups.io/g/oldtools/unsub |
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276645 | Curt Seeliger <seeligerc@g...> | 2022‑12‑01 | Re: knockdown shelf project continues to entertain me |
Oh dear... I know Gary knows this, but others may not. The trigonometry functions in some calculators use radians rather than degrees (so instead of dividing a circle into 360 degrees, circles are divided into 2pi radians, or about 6.283 radians.) So if you tried this on your calculator and got 0.1106 yada yada, and might be wondering what you or Gary did wrong, then you have your answer. Some calculators let you specify units up front. You can also ask google to do the work for you: if you enter "arctan(1/9) in degrees" without the quotes, you'll get the answer in degrees as Gary suggests. If you're not near google or really love your calculator, you can convert radians to degrees by multiplying by (360/6.2832) or 57.295 to get the right answer.. And if that don't do it for ya, Lost Art Press sells something that I think is called a Bevel Monkey that will help you set your bevel gauge to specific angles. It is helpfully labeled in degrees. |
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276646 | Stager, Scott P. <StagerS@m...> | 2022‑12‑01 | Re: knockdown shelf project continues to entertain me |
When I first reads Chuck’s note with the table I was sure that geometry was the basis. But I spent two days trying to figure out what, but the arc tangent never came out right. I double checked that I had the correct numerator and denominator, but it wasn’t even close!! I finally realized that my calculator was set to do angles in radians - Duh!! —Scott Who accepts that occaionally doing something stupid is good for the soul (and the ego). On Dec 1, 2022, at 2:55 PM, gtgrouch via groups.io<http://groups.io> |
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276647 | Chuck Taylor | 2022‑12‑01 | Re: knockdown shelf project continues to entertain me |
Oh dear indeed. In suggesting the use of slopes instead of degrees, I deliberately left out the gory details because it isn't necessary to deal with gory details in order to make furniture. Yes, I did use trigonometry to calculate the degree equivalents in order to illustrate that the results are essentially the same, but it's much simpler not to deal with degrees at all. You don't suppose that 18th-century galoots used degrees in marking out their furniture, do you? It is much easier to set your adjustable bevel gauge using slopes rather than degrees, and much more repeatable. Another practical use of slopes is in evaluating bevel angles of chisels and plane irons. If the width of the bevel is twice the thickness of the blade/iron, then you have a 30-degree bevel. If it's more than 2:1, then you have a shallower angle. If it's less, then you have a steeper angle. For the curious, I used an HP48 calculator emulator on my smartphone (set to calculate in degrees) to make that table, and I did indeed use the arctangent function. Cheers, Chuck Taylor north of Seattle USA |
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276648 | gtgrouch@r... | 2022‑12‑01 | Re: knockdown shelf project continues to entertain me |
Well, for people who know all the angles, it's just a matter of degree. *ducking and running away!* -----------------------------------------From: "Chuck Taylor" To: "gtgrouch@r...", "Curt Seeliger" Cc: "Darrell", "oldtools@g..." Sent: Thursday December 1 2022 5:21:44PM Subject: Re: [oldtools] knockdown shelf project continues to entertain me Oh dear indeed. In suggesting the use of slopes instead of degrees, I deliberately left out the gory details because it isn't necessary to deal with gory details in order to make furniture. Yes, I did use trigonometry to calculate the degree equivalents in order to illustrate that the results are essentially the same, but it's much simpler not to deal with degrees at all. You don't suppose that 18th-century galoots used degrees in marking out their furniture, do you? It is much easier to set your adjustable bevel gauge using slopes rather than degrees, and much more repeatable. Another practical use of slopes is in evaluating bevel angles of chisels and plane irons. If the width of the bevel is twice the thickness of the blade/iron, then you have a 30-degree bevel. If it's more than 2:1, then you have a shallower angle. If it's less, then you have a steeper angle. For the curious, I used an HP48 calculator emulator on my smartphone (set to calculate in degrees) to make that table, and I did indeed use the arctangent function. Cheers, Chuck Taylor north of Seattle USA |
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276650 | Troy Livingston <horologist@w...> | 2022‑12‑02 | Re: knockdown shelf project continues to entertain me |
Chuck, The 48GX was just released when I started school, one of the best $350 purchases I have ever made. The emulator on my iPhone is my favorite app, works well and my phone actually fits in my pocket making it handy when I have to venture out on the shop floor at work. There are several versions. My favorite is the i48 app by Daniel Parnell. Of the versions I've tried it looks the best, works well, and is free. I believe it is also available for android. Troy RPN rules! |
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276651 | Phil E. <pedgerton66@g...> | 2022‑12‑02 | Re: knockdown shelf project continues to entertain me |
TrigoNOmitry, Humph. THAT was off-charter even back in high school when I had to study it. Real Galoots cut by eye, and then do it over until it fits. Trust me on this. Phil E. |
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