99cm is the round number closest to 100 that translates to a round(ish) number in inches. 99cm is 38.97in. They probably split the error between the cm and in scales but in return got a round number for each rotation of the dial for both scales. Wonder why didn't they use 94 cm (37.0079in) though. I guess with 99/39 you just subtract 1 for each rotation, so it's easier to count?
Quite likely they didn't go with 94 because 99 is convenient if you do multiple rotations. 3*99+something is a lot easier to calculate than 3*94+something.
If you loosen the knob at the top, and grip it but the silver shaft, the dial will orient in the direction your hand is moving. Like a caster on a shopping cart. I just was given one with a plastic case, took me half an hour to figure out what its purpose even was! Good video!
We used these to measure quantities on the plans, so many lineal feet of curb and gutter, etc. My 1 minute Engineer’s transit is a Dietzgen and my log-log slide rule is marked Eugene Dietzgen Co., both inherited from my Dad.
I am so intrigued by this. Does it work by gear ratios? I kind of want to make one that is 3d printable. Using this traveling in tabletop can be made so easy. EDIT: I have made one and it works wonders, thinking about selling them now. I did however make mine with 100 (10/0)cm and 40 inches, which is only partially accurate for inches, but that wasnt my goal, 39,37 inches means the 40 marknigs each have an error of about 0,015 which is perfectly fine for tabletop.
I feel like the 99 is to encourage/remind you to keep track of the full rotations you've completed -- and the correct result will always be the number displayed on the dial PLUS the (much smaller) number of full turns that you have in memory.
If the dial was on the back side, it would turn clockwise. Those are for countries that drive on the other side of the road:) I have one, not an antique like yours, mine is only about 30 years old. It has a dial on both sides, one for miles, the other for kilometres. It has a scale built in, three options for 1:10 0000, 50 000 and 25 000. Tricky when your map, those touring maps, doesn’t tell you the scale, I bought it for touring Europe and always had to check the scale by finding a known distance and measuring that. Can’t just run along a road an look for the distance, you have to count how many full revolutions it does. Mine is a nice round 100km on the 1:100 000 scale. Good luck if you want miles (mine was bought in Europe). I can see the small gear on the wheel, another small is gear engages with it and I imagine a large gear engages with that. So a little bit of backlash but less than 0.25mm. The wheel pivot has a pointy button to help you locate the start and end point, a little bit of parallax but good enough for the intended purpose. Good for triangles and measuring on wood too. I see the ones you buy online for $8 are similar to mine in that the full rotation is 100km and whatever in miles. They don’t have the nice point at the bottom though and are likely plastic mostly. They claim to be waterproof but obviously can’t be because the gears are open. Probably means it works when wet. Even underwater for scuba-saboteurs that need to sneak onto secret places.
I’m sure you’ve tried but since I’m on TH-cam I have to ask … I suppose you’ve checked that the knurled disk on top of the tube doesn’t reset the dial?
I reckon the marks stops at 99 so that when you go all the to 100 the needle is at 10. And then if you go round twice for 200 it points at 20. Thats way you can count / keep track. Maybe...?
If the dial starts at 0 (99) and ends at 99 you've counted 100 integers, idk if that solves the math but that is likely the reason it goes to 99 instead of 100 because they are counting from 0 instead of 1
Be careful about measuring coastline! en.wikipedia.org/wiki/Coastline_paradox Edit: Oh, you already knew about that. (I posted before I got to the part of the video where you explain this.)
99cm is the round number closest to 100 that translates to a round(ish) number in inches. 99cm is 38.97in. They probably split the error between the cm and in scales but in return got a round number for each rotation of the dial for both scales.
Wonder why didn't they use 94 cm (37.0079in) though. I guess with 99/39 you just subtract 1 for each rotation, so it's easier to count?
Quite likely they didn't go with 94 because 99 is convenient if you do multiple rotations. 3*99+something is a lot easier to calculate than 3*94+something.
The little swoop looks like it's meant to help tracing the curves, so that it can kind of caster like a shopping cart wheel
If you loosen the knob at the top, and grip it but the silver shaft, the dial will orient in the direction your hand is moving. Like a caster on a shopping cart. I just was given one with a plastic case, took me half an hour to figure out what its purpose even was! Good video!
Woah- I also wondered for a long time what the purpose of the know at the top is. This makes a lot of sense- thanks!
That coastline paradox changed the entire meaning of dimension... Now we have 1.5 dimension things...
Excellent little gadget . Thanks for posting 👍👍
We used these to measure quantities on the plans, so many lineal feet of curb and gutter, etc.
My 1 minute Engineer’s transit is a Dietzgen and my log-log slide rule is marked Eugene Dietzgen Co., both inherited from my Dad.
I am so intrigued by this. Does it work by gear ratios?
I kind of want to make one that is 3d printable. Using this traveling in tabletop can be made so easy.
EDIT: I have made one and it works wonders, thinking about selling them now. I did however make mine with 100 (10/0)cm and 40 inches, which is only partially accurate for inches, but that wasnt my goal, 39,37 inches means the 40 marknigs each have an error of about 0,015 which is perfectly fine for tabletop.
I feel like the 99 is to encourage/remind you to keep track of the full rotations you've completed -- and the correct result will always be the number displayed on the dial PLUS the (much smaller) number of full turns that you have in memory.
That's pretty cool. I need to get one of these now :)
They're easy to find on ebay- cheap too!
If the dial was on the back side, it would turn clockwise. Those are for countries that drive on the other side of the road:) I have one, not an antique like yours, mine is only about 30 years old. It has a dial on both sides, one for miles, the other for kilometres. It has a scale built in, three options for 1:10 0000, 50 000 and 25 000. Tricky when your map, those touring maps, doesn’t tell you the scale, I bought it for touring Europe and always had to check the scale by finding a known distance and measuring that.
Can’t just run along a road an look for the distance, you have to count how many full revolutions it does. Mine is a nice round 100km on the 1:100 000 scale. Good luck if you want miles (mine was bought in Europe).
I can see the small gear on the wheel, another small is gear engages with it and I imagine a large gear engages with that. So a little bit of backlash but less than 0.25mm. The wheel pivot has a pointy button to help you locate the start and end point, a little bit of parallax but good enough for the intended purpose.
Good for triangles and measuring on wood too.
I see the ones you buy online for $8 are similar to mine in that the full rotation is 100km and whatever in miles. They don’t have the nice point at the bottom though and are likely plastic mostly. They claim to be waterproof but obviously can’t be because the gears are open. Probably means it works when wet. Even underwater for scuba-saboteurs that need to sneak onto secret places.
This is SO cool.
The digression is worth the price of admission. 😆
I’m sure you’ve tried but since I’m on TH-cam I have to ask … I suppose you’ve checked that the knurled disk on top of the tube doesn’t reset the dial?
Yeah that seems to be just ornamental- it doesn't do anything.
@@ChrisStaecker that’s disappointing!
If you loosen the knob and hold it by the shaft it works just like a caster on a shopping cart.
instantly subscribed, your channel is amazing
got 99 problems but a 0 aint one
I reckon the marks stops at 99 so that when you go all the to 100 the needle is at 10. And then if you go round twice for 200 it points at 20. Thats way you can count / keep track.
Maybe...?
$3.50 in 1925 is equivalent in purchasing power to about $57.50 today
If the dial starts at 0 (99) and ends at 99 you've counted 100 integers, idk if that solves the math but that is likely the reason it goes to 99 instead of 100 because they are counting from 0 instead of 1
Be careful about measuring coastline!
en.wikipedia.org/wiki/Coastline_paradox
Edit: Oh, you already knew about that. (I posted before I got to the part of the video where you explain this.)