2015 POTD Thread Archive

[Bill C.]

One of those "aha" moments that might benefit someone else down the line:

I'm having to drill and tap about eighty (80) blind holes #2-56 partway through some 3/8" brass rod for a project at work. All of my tap handles, even the smallest, felt too heavy and bulky -- I was scared of breaking the little tap from the weight of the handle alone. So after a bit of head scratching I came up with this. I have three full sets of clock winding keys (previous life/previous hobby) at home and darned if one of them (coincidentally a #2 american key) didn't fit the square on the tap just perfectly. Very light, easy to slip on and off, but still a good solid feel for two-finger operation. Works like a dream, and one of those ideas I thought just had to be shared.

-frank

That is a great idea for those small taps. Looks like it has just enough feel to it as not to over stress and break the tap. Thank you for sharing

 

[Strtspdlx]

Which gears were incorrect? Most of the gears are just idlers and do not affect the tpi. The only critical one is the 16/32 compound gear. Other than that any gear that you can make mesh correctly will work.

The 40t gear was replaced with a 56t gear the rest is as it's supposed to be. And I believe where the 40t is supposed to line up with the 32t compound I have it lined up with the 16t


Regards-Carlo

 

[Bill C.]

Which gears were incorrect? Most of the gears are just idlers and do not affect the tpi. The only critical one is the 16/32 compound gear. Other than that any gear that you can make mesh correctly will work.

That is correct, just the two gears control the number of threads per inch. The rest just fill in the gap between the two.

 

[Rob]

In your post under the atlas forum you said you set it for 4tpi. If you look at your chart on the QCGB you will see that the settings are the same for 4 tpi and 8tpi. The only difference is the sliding gear. In this case you have it in the out position so you should have cut 8tpi. Some pictures of your gearing setup would be nice. Replace the 40t with a 56t should not affect any ratios for thread cutting.

 

[Strtspdlx]

Rob, I never understood the in/out labeling on the gear box. Exactly what does that mean?


Regards-Carlo

 

[turnitupper]

Followup on the prior posting: - the tap worked fine. I guess I'll engrave it with "5/16 - 32 UNEF", heat treat it, and add to my collection of odd taps. For some other POTD, I need to make a better storage container for my UNC taps and dies. Back around 1977, I got a cheap set at a garage sale for maybe $3 and still have the sheet metal/styrofoam tray that still works but doesn't hold my whole collection. I suppose the easy way would be to drill and route holes into a 2x4 and make a matching top. As I gradually augment my collection with additional taps (e.g. bottoming taps as needed, and most recently, some size 0, 1, 2, and 4 for my in progress artillery scale model), maybe I'll leave open holes for a complete set. And for storage and access, I'd make a few separate boxes rather than one monster unit. A box for #12 and below, another for 1/4" and up. Anybody got ideas on this? (My metric taps and dies are a rather new Craftsman set, and are in a molded plastic case.)
Greg

Greg,
If your blow moulded case is a little thin, you can fill the voids underneath with cheap Silicone sealent, I have even used it on a cheap $8 socket set case and after 20 odd years the case is still good. Can't say the same for the socket set.
John.

 

[chevydyl]

If you open the gear cover on the end of the head stock, there is a sliding gear, there an In position and an Out position, take a look you should be able to tell what's going on.

 

[Rob]

Rob, I never understood the in/out labeling on the gear box. Exactly what does that mean?


Regards-Carlo

That is the position of the sliding gear, normally a 40t. When it is slide to the left as you are facing the lathe it is in the out position. When it is slide to the right or closer to the headstock it is in the in position.

When in the out position the 16/32 gear reduces the speed of the lead screw by 1/2.

 

[hman]

Today I needed a steel “washer” of about 4” OD and 2.03” ID. I used a 4 1/4” hole saw to cut a round slug from a sheet of 11 gauge (1/8” steel). Chucked it in the lathe and used a 2” hole saw to cut a slightly undersized ID. The 2” hole saw would have hit the flats of the external jaws, but I routinely cut from both sides when using hole saws, so as to get a cleaner result.

The problem then was how to bore the ID without running the tool into the jaws. What to use for spacers? AHA! I have a bunch of 8mm tall, 8mm diameter rare earth magnets. Stuck them on the jaw flats, then stuck the part on. The magnets even held the part in position while I tightened the jaws - without having to hold it in place by hand!




Just for fun, I miked a few of the magnets I have. They all seemed to fall within a .002” range in height. Not too bad.

HOWEVER ... these magnets absolutely LOVE swarf! And any crumbs that get on the magnet may cause the part to wobble. So be aware of this.

 

[Strtspdlx]

That is the position of the sliding gear, normally a 40t. When it is slide to the left as you are facing the lathe it is in the out position. When it is slide to the right or closer to the headstock it is in the in position.

When in the out position the 16/32 gear reduces the speed of the lead screw by 1/2.

Well that makes sense. I had to put it in the out position because the banjo lockdown interferes with the 56t gear when it is in. Luckily 90% of the threading is in the out position. And I believe all the feeds are out also. Lucky me.


Regards-Carlo