2013 POTD Thread Archive

[savarin]

Using the same boring bar that I had bored the gear with, I ground a 7 degree relief angle on a peice of HSS tool bit that had the same dimension as the key that I wanted to cut. In this case it was 1/4" . I simply ground a 7 degree end clearance angle, hand honed it with a small stone and oil, and mounted the tool bit in the boring bar holder with the square top edge facing the chuck and the 7 degree relief angle pointing back towards the tailstock. By eye, I rotated the boring bar until it looked like the tool bit was roughly horizontal.

This keying procedure is done without power to the lathe of any kind but muscle power. I engaged the back gears of the lathe to eliminate the spindle turning on me while keying. I also drove a wooden wedge between the cone pulley and the housing. Then I advanced the carriage towards the chuck until the tool bit was close to the bore opening and used the cross-slide to adjust until the tool bit was in close contact with the bore.

Whether the tool bit is exactly horizontal or vertical or anywhere in between is not important. What matters is that both edges of the tool bit are in contact with the bore at the same time. I rotated the boring bar and manipulated the cross- slide and carriage until both points of the flat were in contact. I then advanced the cross-slide .001" and used the carriage handwheel to push the cutter into the bore. I visually verified that it was cutting equally on both corners and made sure that the boring bar was snug and continued to feed 001" at a time and running the tool in and out.

You need to be patient and not be tempted to increase the cut to hurry it along. Just relax and get into a rhythm..... it took about 5 minutes to cut this keyway. I don't have keyway broaches as of yet and this was a method that was passed along to me that served the purpose and the end result was very good.

I hope that I haven't been too long in the tooth in my explanation and that I have answered your question. Don't hesitate to ask more questions of me. I am fairly new to machining and am here to learn...

Cheers...

Brian

Thats how I did it on my 9x20. I would like to say it was successful in as much I did cut the keyway, but, I broke 3 teeth on the rack and damaged a couple of teeth on the pinion.
Upon further investigation I found that the pinion was only able to engage the teeth on the rack by 2mm (0.078")
I have since re-built the pinion shaft to produce full width engagement but the new rack has its holes drilled in the wrong positions so I am in the process of fixing this part now.
I would think on a quality lathe this problem wouldnt rear its ugly head but definitely worth checking out before doing what I did.

 

[clevinski]

I made the arbor for a slitting saw... I'll make the cap tomorrow.

 

[clevinski]

Finished slitting saw arbor with cap and blade...

 

[DaveInPA]

I completed this fire piston today. It's made from 6061 aluminum, a #6 O-ring, and a 6d nail. Now I need to make some char cloth to use for tinder.

 

[stern]

Decided to start working on the coolant system for the mill since yesterday I went out and picked up a parts washer pump and nozzle to use. Needed to make a mount for the nozzle as well at connections for the supply and return lines. Since I had a couple of scrap bits of aluminum I figured why not use them.






Used a chunk of 3/4" aluminum and made it the size needed, I then drilled passages in the block for coolant flow and fittings for a control valve (to regulate the flow rate to the work). Tapped the holes for compression type 1/4" copper fittings (I have tons for work) and the coolant hose. Temp fit went well.



Coolant enters on the right end and goes through the valve to the hose. A second tap is taken from the ose and returned to the coolant tray via a second valve. This allows me to change the flow rate and not straign the pump, as excess will just be returned to the resivour (same way I did my lathe one).



Then channeled out the center for a recess to put the on/off switch (decided to use a rocker type). Since the plate isnt deep enough for the switch and wiring, I made a second smaller block (1" alluminum) to mount over the base plate and give me a reces deep enough to hold the switch.



The channel in the top block is sized to fit the switch (bottom is stepped open to stop wire rubbing) while the bottom block has more room to hold the wiring. I will mount the switch on a sheet of stainless and screw it to the top block.

 

[outsider347]

My shop is quite small, so my machinery needs to be compact & have more than use.
Started out as a roller / saw support.
Then I bought a Shrink er /Stretcher & needed a stand
Then I needed a fixed stand to hold my fixed dollys for some sheet metal work
folds away for wall hook storage

sorry about the Pics are a bit out of order & turned, not sure how to fix

Tks for your interest

 

[clevinski]

I completed this fire piston today. It's made from 6061 aluminum, a #6 O-ring, and a 6d nail. Now I need to make some char cloth to use for tinder.

Ha! Fire piston! I had to Google it to find out what it is... very cool!

Where does the tinder go?

 

[Hawkeye]

Dave,

Nice fire piston. I changed the O-ring on mine today, in preparation for my lunch fire on a kayak day trip. Got a glow in the usual couple of pumps. At lunch time, no way I could get an ember. I should make a new unit. The old one is made from a small flashlight with a wooden piston.

I used pieces of blue jean leg for the char cloth. It works very well. Today's test piece fell into some water in the sink after it lit and kept on glowing for quite a while.

347,

If you rotate your photos in your hard drive before you upload them, they will be right-side-up in your post. Right-click on your photo file, then select 'Rotate Clockwise' or 'Rotate Counterclockwise'.

If you use the 'Insert Image' button on the toolbar, you can put your photos in one at a time and they will stay where you inserted them. Selecting a number of photos at once with the 'Manage Attachments' facility will allow the software to put them in alpha-numeric order.

 

[pestilence]

Today I re-mounted my x axis DRO, got my rotary table set up and rounded off the ears on my vice handle head. Thanks go out to whoever invented carbide tooling and the people who liquidate large lots of tooling on eBay

 

[DaveInPA]

Ha! Fire piston! I had to Google it to find out what it is... very cool!

Where does the tinder go?

The tinder goes in the cavity in the end of the piston.