2016 POTD Thread Archive

[savarin]

I guess you could say I did this in the shop today.
serviced the gears and brakes on my low rider recumbent in preparation for a ride Friday.
(this one http://www.hobby-machinist.com/threads/a-couple-of-my-bicycle-builds.8521/ )
Took it for a test spin and all was fine.
Rather than walk it back into the shop I elected to ride it in.
Bad move, traveling at less than walking pace the rear wheel rode over the extension cord on the floor which skipped the rear wheel sideways to the left throwing me into my stash of steel sideways head first.
I was trapped, jammed under the bench, right arm trapped under me, head in the ends of the steel, bike jamming me in place.
Luckily My mate was handy to pull me out and it only needed 4 stitches to the ear and surrounding area.
Reading back it seems my comments waited 4 years to bite me.

 

[mattthemuppet2]

dang, that's a crazy crash!

Finished my poly-v countershaft project last night:

top speed on the smallest countershaft pulley. The motor sounds like it's about to take off at that speed, lots of air movement from the flywheel fan too.



Speed range in that countershaft pulley went from

60-248rpm backgear (25-100% motor speed, below 25% is useless), 400-1650rpm direct

to

26-148rpm backgear, 240-990rpm direct.

Much more useable range in my opinion and I still have 3 more countershaft pulley ratios to play with if I need higher speeds in backgear or direct drive. Still mulling replacing the spindle/ countershaft pulley with a poly-V belt, but that would require cutting a gear and I'm not there yet

Unfortunately there's still a bit of vibration coming from the motor - a bit from the motor itself and a bit from the flywheel, which is balanced but astonishingly out of round. Still way way less than what there was when I started this whole exercise and shouldn't affect the finish. More importantly the vibration doesn't increase with motor or spindle speed, which it did before, so I can now use that whole speed range if I want to.

A list of stuff I've done to reduce vibration:
link belts - helped, but not much
replaced off center and oversize spindle pulley bushings - helped a lot
replaced countershaft bushings and used an on-size rod for the countershaft - helped a bit
replaced V-pulleys on motor and countershaft with poly-v pulley and flywheel - helped a bit

You can still feel some vibration through the bench, but not much through the lathe. Overall I'm super happy - both with the result and with the fact that I can get on with other projects now!

 

[stupoty]

Broke an M2.5 tap , ahhhhh , managed to tap (accidental pun) it round and round with a center punch to remove it , yay

Stuart

 

[Jason Annen]

Nearly finished the stub arbor for my VN slotter attachment. This was going to be a spline adapter, but that will have to come later.





Jason

 

[FOMOGO]

Really nice job on the arbor. Mike

 

[TOOLMASTER]

Made more name tags for my equipment...and one USA.

 

[HBilly1022]

Made a tapered pin with internal threads for my Bobcat and learned some new things about aligning parts in the 3 jaw. I've had problems in the past with getting the part concentric when flipping it end for end, even when using center drills and tail stock centers. Could never seem to get the tail stock end to be perfectly aligned. Today I held the part between the tail stock and fairly loosely in the 3 jaw and used the DTI to check the alignment at the tailstock. Initial readings showed it was out of alignment by 0.005". As I slowly tightened the 3 jaw I would look for the high spot and then give the work piece a little tap with a wooden block until I got it to within 0.001". Also tried using the "nudge" technique Toolmaster posted when drilling the through hole. It worked awesome. Thanks again Toolmaster. Anyways here are some pics.

 

[intjonmiller]

I made (most of) my first lathe spider (outboard type). This is from a 3' rod of, I think, HDPE. It was so easy to work I was tempted to mount a screwdriver in the toolpost to see how it would cut.

Maybe it will work out great in actual use, but I figure it's a rough draft with cheap, easy material for practice. After I use it a little I'll decide if I want to redo it in aluminum or steel.



This is my first time boring, though I took a shortcut with a 1-1/16" carbide Forstner bit to hog out most of the material. Gorgeous, decorative-grade swarf.

This was also my first time doing any threading, and it was internal. I don't have a proper internal threading tool but I had a cheapie boring tool from a HF lathe tool set my dad picked up at some point, and it was close enough for use with this very forgiving material. I guess making an internal threading tool should be my next shop project.

Finally this was my first time using the lathe to mark out for an operation to be completed on another machine. My lathe has a 72 tooth bull gear so I counted off 18 teeth and marked all around for 90 degrees, and again every 24 teeth for 120 degrees. I figure I'll probably only use the "3 jaw" configuration, but it only added a couple minutes to do the second set so why not? Easy to handle square or eccentric work if I ever need to.

Hopefully tomorrow I can drill and tap the holes (on a v-block on my better drill press).

I'm having fun. :-D

 

[thebigron]

I've been meaning to post a couple of photos of my 10 lifetimes supply of short stock, all flavors, grades, stainless, brass, copper, carbon, aluminum, cast, and whatever else Dad had accumulated in 80 years as a tinker/machinist. He was a child of the depression and could throw away very little. It's hard for me to do too, but I have let go of 20% as I have moved it from his shop to mine in the last year or so after he passed. It's awfully nice to go to the lot and pull out something close, and I'm only half done moving material in. It would average length probably around 28". Thank you, Pop.

 

[TOOLMASTER]

jeez