- Joined
- Dec 26, 2017
- Messages
- 60
Nothing about this went right but it came out ok (if you don't look at it too closely, or at all).
I had some 3/4" brass round stock left over (ok... it was just laying there and I felt the need to turn. The only thing left over about it are the chips in the vacuum cleaner) and it seemed like a really good idea to turn it into a scale model of a baseball bat. So I drew a real bat in Fusion 360, while doing so I called Fusion 360 a lot of bad names... did I type that out loud, I mean masterfully and quickly drew a perfect 3D model of a bat (<--- this is a lie, it took forever). Once I had it drawn, I scaled it down, made a drawing, dimensioned the drawing to 2 decimal places, and printed it. From there I created a high precision version of the bat on my mini-lathe.
Check these tolerances out.
As scaled length: 9.590" plus some more (I made a special feature in my drawing that couldn't be dimensioned)
As built: 6.5625" ± a tad (note the precision... I'm well within 4" of target)
As scaled minor diameter (handle): 0.280"
As built: 0.250" (again... unbelievable tolerance. Within .5")
Scaled major diameter (end of bat): 0.770" <--- this was harder to do than you think. I used 3/4" stock.
As built: 0.625" (absolutely phenomenal, who says you can't be precise with a mini lathe)
As drawn taper: 2.16°
As built: Why do you ask? Is it really that important to know? There might be more than one taper
Other as drawn dimensions: Needless information that would only confuse the matter...
Ta da!! The photo doesn't do it justice and I'm glad
Ok, ok... I messed up a simple bat and the photo is of what I was able to salvage. Things I've learned:
(1) Brass throws chips in showers of sharp little "chiplets". Wear shoes... just sayin...
(2) Brass likes a certain kind of tool bit. I don't have that tool bit.
(3) You can't make a part out of stock that's smaller than your largest dimension.
(4) Using the compound to turn a taper must be a satanic ritual that's best to be avoided.
(5) Fusion 360 does not come with an Easy Button.
(6) Order of operations is apparently important.
(7) Files leave marks that are just as bad as tool marks
(8) Sanding tool marks out doesn't seem to work very well if the emory cloth is 80 grit (or whatever grit plumbers cloth is). The marks just change, they don't go away.
(9) If your stock has a hole for a live center make sure you stop "behind" the hole if you don't want a hole in the end of the part.
(10) Parting off something on both ends is tricky... like don't do that tricky.
So what really happened? Lots. This is the 4th "thing" I've done on the mini lathe. All things considered, it's a surprisingly good little machine (the operator, not so much). I have no idea if what I'm about to say is correct but- In hindsight I think I should have machined the small end of the bat first and then "pulled" the taper back to the big end with the compound instead of pushing it from the big end to the little end. Since my stock was too short and a little too small in diameter I just eyeballed where to start the taper and "pushed" the tool bit toward the head stock. Eventually I had to deal with the handle end but what I didn't realize, until it was too late, was that the taper setting was too shallow. The drawing gave me the machining angle and I brilliantly divided that by two and set the compound at 1° (with an angle block) instead of 2°. By the time I figured it out I had enough of a mess on my hands that I was in salvage mode. I eyeballed the compound at a little over 2° and made a version of the bat with lots of guessing...
Mini lathe's are good teachers.
I had some 3/4" brass round stock left over (ok... it was just laying there and I felt the need to turn. The only thing left over about it are the chips in the vacuum cleaner) and it seemed like a really good idea to turn it into a scale model of a baseball bat. So I drew a real bat in Fusion 360, while doing so I called Fusion 360 a lot of bad names... did I type that out loud, I mean masterfully and quickly drew a perfect 3D model of a bat (<--- this is a lie, it took forever). Once I had it drawn, I scaled it down, made a drawing, dimensioned the drawing to 2 decimal places, and printed it. From there I created a high precision version of the bat on my mini-lathe.
Check these tolerances out.
As scaled length: 9.590" plus some more (I made a special feature in my drawing that couldn't be dimensioned)
As built: 6.5625" ± a tad (note the precision... I'm well within 4" of target)
As scaled minor diameter (handle): 0.280"
As built: 0.250" (again... unbelievable tolerance. Within .5")
Scaled major diameter (end of bat): 0.770" <--- this was harder to do than you think. I used 3/4" stock.
As built: 0.625" (absolutely phenomenal, who says you can't be precise with a mini lathe)
As drawn taper: 2.16°
As built: Why do you ask? Is it really that important to know? There might be more than one taper
Other as drawn dimensions: Needless information that would only confuse the matter...
Ta da!! The photo doesn't do it justice and I'm glad
Ok, ok... I messed up a simple bat and the photo is of what I was able to salvage. Things I've learned:
(1) Brass throws chips in showers of sharp little "chiplets". Wear shoes... just sayin...
(2) Brass likes a certain kind of tool bit. I don't have that tool bit.
(3) You can't make a part out of stock that's smaller than your largest dimension.
(4) Using the compound to turn a taper must be a satanic ritual that's best to be avoided.
(5) Fusion 360 does not come with an Easy Button.
(6) Order of operations is apparently important.
(7) Files leave marks that are just as bad as tool marks
(8) Sanding tool marks out doesn't seem to work very well if the emory cloth is 80 grit (or whatever grit plumbers cloth is). The marks just change, they don't go away.
(9) If your stock has a hole for a live center make sure you stop "behind" the hole if you don't want a hole in the end of the part.
(10) Parting off something on both ends is tricky... like don't do that tricky.
So what really happened? Lots. This is the 4th "thing" I've done on the mini lathe. All things considered, it's a surprisingly good little machine (the operator, not so much). I have no idea if what I'm about to say is correct but- In hindsight I think I should have machined the small end of the bat first and then "pulled" the taper back to the big end with the compound instead of pushing it from the big end to the little end. Since my stock was too short and a little too small in diameter I just eyeballed where to start the taper and "pushed" the tool bit toward the head stock. Eventually I had to deal with the handle end but what I didn't realize, until it was too late, was that the taper setting was too shallow. The drawing gave me the machining angle and I brilliantly divided that by two and set the compound at 1° (with an angle block) instead of 2°. By the time I figured it out I had enough of a mess on my hands that I was in salvage mode. I eyeballed the compound at a little over 2° and made a version of the bat with lots of guessing...
Mini lathe's are good teachers.
