2016 POTD Thread Archive

intjonmiller said:

I got the double layer plywood workbench top (with solid wood edging) assembled and gave it four coats of water-borne polyurethane. Greatly reduced the local gnat population in the process. It never fails. Dozens of those suckers landed after every coat. Compressed air blasts cleared out most of them, save a limb or two.

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The top required nearly three full sheets of 3/4" plywood. It is HEAVY. Attached it to the metal base with 25 wafer head lath screws through predrilled holes distributed around the frame. It is now even more rigid and vibrations are somewhat dampened. The 400+ pound wood slab I will be storing in the back of the base will also help.

Weeknights this week I will be moving the lathe, surface grinder, jointer, and dust collector out of the way and moving this into place, then leveling it. Saturday I FINALLY pick up the mill and bring it home.

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Go buy a gallon of oil based floor poly to top coat your bench!

Years ago we got a good deal on close out laminated oak flooring and glued it in then sanded it all and then asked go the best they had at the box store and it was the water based stuff and it went on great and was fantastic...until we spilled some rubbing alcohol on it and it blisters badly.

Someday will strip and redo but that smacks of effort.

Test your surface by coating a scrap of wood then test your different fluids to see if it holds up.

We have a bench too with the melamine or whatever that white stuff is and it holds up great.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk

I almost finished the linear actuator I have been working on for the last day or so. I need a precision linear actuator for a project that I'm working on, needs to hold 0.01 mm. I originally tried an air cylinder and a hard stop, but using enough air pressure to just move the air cylinder proved to put too much pressure on the material I was trying to feed with it. So onto plan ''B'', a precision ball lead screw and a stepper motor. I just happened to have a few ball screws/nuts on the shelf that I picked up at an auction. This one is 20 mm dia, 10 mm pitch, by 1 meter long.

Due the the way the feeder has to operate, the ball screw can not turn, so I have to turn the nut. This requires that the nut be captured in bearings, both radial and thrust. Then also requires a drive mechanism.

So first the bearing housing starts out as a 4x4x5 inch block of aluminum. Block squared up and cover plate bolt holes and a pilot hole drilled for the pocketing operation.



Pocketing the pulley clearance.


Pocketing the roller bearing pocket, and the thrust bearing pocket below. By the time this is done the end mill will be reaching down 3.875 deep to pocket for the thrust bearing, then through for the screw clearance. I used a 1/2 x 3 inch end mill for the first part of the operation then switched to a 3/4 x 4 to reach the bottom.


Then to the boring head to final bore for the bearing. The bearing bore wasn't very pretty, no matter what I did it chattered. I tried different feeds, speeds, and grinds. Nothing worked, so I just let it chatter. I think I need to build a better arbor to hold the boring head. Currently using a 1 inch straight shank in an endmill holder. I need to build a 30 taper shank that directly screws onto the head.


Then on to the cover plate/motor mount. 5/8 inch thick aluminum.



Once the work was done on the bearing side, then flip it over and do the work on the other side.

First, machine a 0.125 deep pocket in the MDF to locate the part. This absolutely locates the part and then it also requires minimal clamping to hold it in position.


Done with the motor side.


Drilling & reaming the drive pin holes and finishing the pulley to proper thickness by removing all but 0.030 of the hub.


The roller bearing installed in the housing and one thrust bearing in the bottom.



The drive pins (dowel pins) engage with the bolt holes in the ball nut. This is the only way I could come up with to drive the nut. The nut is hardened so no way to tap the holes, and no clearance for bolt heads on the back end. The bolt holes are about 0.255 diameter, so by slightly offsetting the 0.250 dowel pins in the pulley it has near zero backlash. The pulley is held in place by the thrust bearings.




Here is the exploded view of the assembly. That grease notch in the ball nut rides right over the rollers with no problem.


These four grub screws set the axial preload. They will get a drop of blue LocTite on final assembly.


And the assembled view


This little ''car'' will be attached to the ball screw to keep it from rotating.


And the rear view




I still need to bore the motor pulley to size, make a belt guard, and attach the car to the ball screw. I hope it will drill & tap, it's a bit hard.

intjonmiller said:

"It's okay, Sweetie! It followed ME home. And it isn't even working. See the broken roller? I didn't get it for you."

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kvt said:

I have a fan running in the there full time. but that does not seem to help much at times. Have not figured out if it is the humidity or what, but it just does not seem to cool off in there.
Do not have any windows, except in the garage door, so no place to put any window AC or something. Could leave the door to the house open and see if it cools me off a bit, but then have to put up with the swarf and stuff getting into the house. What is better be hot, or have the other half ****** off because she got a sliver of something in her foot.

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savarin said:

we used to have a similar place here in townsville that did that with aluminium and also allowed you to rummage through their drops bin.
They sold out and the new company advertise they cut to size but what they really mean is you order the whole length or sheet and they will cut that to your size. Grrrrrr.

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I made these today a 24 tooth and a 36 tooth DP16.



I have made single pointed gears over the years and some even turn out kind of working OK but some not so well.

I finally broke down and bought a set of these.


These take all the guess work out of the project and produce great teeth that rival store bought.

Blank turned to size.


I cut them in two passes the picture below is during the first pass.


I am happy
Thanks for looking.

Ray

I'd be happy too. Nice job on those. Mike

This mod has probably been posted a hundred times but here's my simple Spindexer mod . I wanted to be able to put the spindexer in my vise for "quick" work that's less critical .
I put it in the vise and right away I could see the base was not square, the base is a little wider at the front , the base is the shape of a keystone . And it's also thicker, 0.530" rear and 0.575" front .
I removed all the paint from where i needed to clamp, then ground off the lumps and burrs with a carbide tile blade in an oscillating multi tool (dewalt DCS355) . Removing the burrs and lumps took it down to about 0.550" in the front so I used some copper sheet as a shim and clamped the spindexer in my vise on it's side. At that point, i could extend it's shaft out about 3" under my quill and indicate to flat (square) off that . Then i milled the sides square and re-painted it with some leftover '77 ford blue.
I have a feeling i'm not done with this thing yet ...all part of the learning process
-----------------------------------------

tq60 said:

Go buy a gallon of oil based floor poly to top coat your bench!

Years ago we got a good deal on close out laminated oak flooring and glued it in then sanded it all and then asked go the best they had at the box store and it was the water based stuff and it went on great and was fantastic...until we spilled some rubbing alcohol on it and it blisters badly.

Someday will strip and redo but that smacks of effort.

Test your surface by coating a scrap of wood then test your different fluids to see if it holds up.

We have a bench too with the melamine or whatever that white stuff is and it holds up great.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk

Click to expand...

What you are describing sounds like it could be something wrong in the application process, such as improper thinning or being out of the specified temperature range. The water is just the solvent keeping the polymers from cross-linking in the jar and during application. Once the solvent (mineral spirits in the case of oil-based polyurethane) evaporates the polymers cross-link. The result is the same with either product. But their handling characteristics are different. I normally use oil-based because I prefer the warm tone that it adds, but in this case I was limited to a fairly narrow application window due to the shorter, cooler days, so the *much* faster dry time of the water-borne poly was the obvious choice.

I've not had any problems with water base polyurethane. I use it all the time on my wood projects. The stuff is tough as nails and impervious to everything I've ever spilled on it.

Another good top for a work bench is hard Masonite over a solid base. It is pretty tough, but when you bugger it up with oil, solvents, paint, scratches and gouges, you just replace it.

Finished the drawbar this morning,



Had to shorten the bar (1/2" pipe) by 1" to adjust to the finished sleeve.

I made the sleeve from a piece of..something...I had in the bin. I believe it is a 1045 or 4143 annealed. Just a guess cause it was painted white on the end. I know, I know, that is not a definitive way of telling. But. It did not cut like 1018 or 12L14, it cut more like some tool steels I've cut in the past. So just a guess.


I did not harden the sleeve mainly because the sleeve that came with the lathe for the 2J collets, or SB #2 collets if you prefer, was not hardened. But if this is a tool steel and I need to, I can always go back and harden it then grind later.

Nice drawbar! I've had the same project on my mind for a couple years now. I just finished some drawings for my design which is almost the same as yours except it will have a thrust bearing.
How is that brass sleeve connected to the bar? Press fit? Threaded?