The Machine Work Thread

[Bigblue&Goldie]

None of the above lol. Rigid tapping. I just run taps in ER collets.

What's an "ER" collet?

 

[kazlx]

It’s just a type of collet. Same as an R8 or whatever. Just a different style. They come in a bunch of different sizes and have a grip range of like .100. They are very common for holding tools in CNC machines. So you need the tool holder with the correct taper for your machine, mine is Cat40 which is also super common. Then you buy the correct collet size both to fit the holder and to fit the tool you put in it.

https://www.maritool.com/Tool-Holders-CAT40-ER-Collet-Chucks/c23_25_42/index.html

 

[stioc]

None of the above lol. Rigid tapping. I just run taps in ER collets.

Baller!

 

[Bigblue&Goldie]

It’s just a type of collet. Same as an R8 or whatever. Just a different style. They come in a bunch of different sizes and have a grip range of like .100. They are very common for holding tools in CNC machines. So you need the tool holder with the correct taper for your machine, mine is Cat40 which is also super common. Then you buy the correct collet size both to fit the holder and to fit the tool you put in it.

https://www.maritool.com/Tool-Holders-CAT40-ER-Collet-Chucks/c23_25_42/index.html

Gotcha. With the CNC does the tap "pull" itself down like it does when power taping in a chuck or collet on a Bridgeport?

 

[stioc]

Gotcha. With the CNC does the tap "pull" itself down like it does when power taping in a chuck or collet on a Bridgeport?

Yep, and they can break but if the CNC machine has the rigid tapping feature then it prevents that from happening by adjusting the feedrate with the speed of the spindle via the feedback mechanism. At least that's how I understand it -my home built CNC doesn't have that feature, no encoders etc.

 

[bullnerd]

Gotcha. With the CNC does the tap "pull" itself down like it does when power taping in a chuck or collet on a Bridgeport?

No, not like a tap matic or free handing on a Bridgeport. The thread pitch is used to calculate the feedrate for the z axis (or whatever axis) and the tap is powered in and out. It is "rigid" the whole time.

 

[Bigblue&Goldie]

No, not like a tap matic or free handing on a Bridgeport. The thread pitch is used to calculate the feedrate for the z axis (or whatever axis) and the tap is powered in and out. It is "rigid" the whole time.

Gotcha. That's what I figured, but I have zero CNC experience.

 

[stioc]

But it depends if the CNC machine supports Rigid Tapping. CNC by itself doesn't automatically mean Rigid Tapping can be done. Which is what I was trying to say earlier that in a non-Rigid tapping senario it's the same as a manual mill.

 

[Bigblue&Goldie]

But it depends if the CNC supports Rigid Tapping. CNC by itself doesn't automatically mean Rigid Tapping can be done. Which is what I was trying to say earlier that in a non-Rigid tapping senario it's the same as a manual mill.

I've seen that, but I know he has a big Fadal machine. I would like to get a Tapmatic tapping head for the Bridgeport, but I'll just powertap out of a drill chuck for the time being.

 

[stioc]

I've seen that, but I know he has a big Fadal machine. I would like to get a Tapmatic tapping head for the Bridgeport, but I'll just powertap out of a drill chuck for the time being.

Power tapping works as long as you don't break the tap (tapping into hard metals), that would ruin the day. I don't have a 3 phase motor (i.e. no quick reverse) so when I built a fixture plate with 60 holes in it I used the CNC to walk each hole then with a tapping guide I started the threads by hand. After that I 'power tapped' the started holes with a cordless drill by hand. It wasn't too bad. If I had to tap holes like that more often I'd invest in a tapmatic.

 

[Bigblue&Goldie]

My Bridgeport is 3 phase via VFD, so I really shouldn't be doing too much instant reversing. On through holes it's not a big deal as I can shut the machine down and apply the brake, but on blind holes I really don't want to chance it.

 

[matt_i]

I have a VFD on my drill press for power tapping (its a 20" Clausing if that matters). Here's how it works.

- selector switch for Drill/Tap mode. In Drill-Mode the spindle runs clockwise/forward rotation and the control pot is used.

- In Tap mode the spindle runs in Reverse/counterclockwise and I dial it down to around 8Hz. Tap is just chucked by friction just like a drill bit. There's a footpedal so when you want to start tapping you grab one of the tri-handles and step on the pedal. The spindle ramps to a stop, then reverses direction to the correct one for tapping a right hand thread. So enter the tap into the work and apply light downpressure. When I have sufficient depth I step off the pedal and the tap backs itself out.

Its a simple parameter setup using one of the VFD's inputs and its low-voltage power supply. The footpedal is a signal to tell the VFD to change rotation direction.

This works very well when there's a pile of parts to be tapped.

For one hole, usually in a Bridgeport I just chuck the tap immediately after drilling the pilot hole because the alignment is never going to get better than that. Put the spindle back-gear lever in Neutral and use one hand to power-twist the exterior of the chuck and the other to apply light downpressure to the spindle. Once started one can use 2 hands on the spindle-twist. It works well up to about 1/2-13 or for tapered taps where its hard to get sufficient torque and then a spring-loaded tap guide and longer tap handle should be used. I've done guessing 5000 holes this way. Stock up on spiral-point "gun" taps and save the 4 fluters for when you need a bottoming tap all the way to the bottom of a blind hole.

 

[Bigblue&Goldie]

I have a VFD on my drill press for power tapping (its a 20" Clausing if that matters). Here's how it works.

- selector switch for Drill/Tap mode. In Drill-Mode the spindle runs clockwise/forward rotation and the control pot is used.

- In Tap mode the spindle runs in Reverse/counterclockwise and I dial it down to around 8Hz. Tap is just chucked by friction just like a drill bit. There's a footpedal so when you want to start tapping you grab one of the tri-handles and step on the pedal. The spindle ramps to a stop, then reverses direction to the correct one for tapping a right hand thread. So enter the tap into the work and apply light downpressure. When I have sufficient depth I step off the pedal and the tap backs itself out.

Its a simple parameter setup using one of the VFD's inputs and its low-voltage power supply. The footpedal is a signal to tell the VFD to change rotation direction.

This works very well when there's a pile of parts to be tapped.

For one hole, usually in a Bridgeport I just chuck the tap immediately after drilling the pilot hole because the alignment is never going to get better than that. Put the spindle back-gear lever in Neutral and use one hand to power-twist the exterior of the chuck and the other to apply light downpressure to the spindle. Once started one can use 2 hands on the spindle-twist. It works well up to about 1/2-13 or for tapered taps where its hard to get sufficient torque and then a spring-loaded tap guide and longer tap handle should be used. I've done guessing 5000 holes this way. Stock up on spiral-point "gun" taps and save the 4 fluters for when you need a bottoming tap all the way to the bottom of a blind hole.

Do you have capacitors to soak up the energy when you reverse the spindle? What is your ramp down rate (how many seconds)?

 

[matt_i]

Do you have capacitors to soak up the energy when you reverse the spindle? What is your ramp down rate (how many seconds)?

Its just the ramp in the VFD and I can't exactly quote the # of seconds, its probably a 1 second change vs. an instant plug reverse. I'm only turning 20Hz and there isn't a lot of mechanical inertia attached.

 

[whateg01]

Do you have capacitors to soak up the energy when you reverse the spindle? What is your ramp down rate (how many seconds)?

A braking resistor allows the VFD to stop (nearly) instantly at those speeds and reverse. This is how my lathe is setup. I can flip the lever from fwd to rev at whatever rpm and it slows to a stop and goes the other way, at least until I burn up the braking resistor.

Dave

 

[ClappedOutBport]

My Bridgeport is 3 phase via VFD, so I really shouldn't be doing too much instant reversing. On through holes it's not a big deal as I can shut the machine down and apply the brake, but on blind holes I really don't want to chance it.

I've been instant reversing motors on VFDs for about 4 years now. Not using the vfd controls either, using the machine switch, as the vfd ran more than one than one machine. The chinese VFDs are more tolerant than people think. YMMV.

Reversing with the VFD puts the heat into the resistors, but I think reversing with a drum switch puts the heat into the motor.

I was tapping today with my camelback, and I'd flip it in reverse at full speed, no problems. Then again it's run off an oversize VFD.

 

[matt_i]

Reversing with the VFD puts the heat into the resistors, but I think reversing with a drum switch puts the heat into the motor.

Keep in mind the VFD is pushing out energy to a load which is sinking it, in an instant the energy has nowhere to go. In the next instant its opposed by the back-emf of not only a stationary motor but one spinning the opposite direction.

Think in mechanical analogy, you're pushing snow with a pickup truck. Then you hit a medium duty snowplow blade head-on which you then find medium duty truck was coasting at you in the opposite direction and so eventually you can reverse its direction. Can the pickup truck take this? Probably for awhile and depending on the mechanical inertia behind the truck. But you can see how it can shorten the life.

The thing saving the enterprise is the low amount of horsepower that a manual machine tool requires. But get to rated hp capacity and try that you will be buying a new VFD.

 

[ClappedOutBport]

Keep in mind the VFD is pushing out energy to a load which is sinking it, in an instant the energy has nowhere to go. In the next instant its opposed by the back-emf of not only a stationary motor but one spinning the opposite direction.

Think in mechanical analogy, you're pushing snow with a pickup truck. Then you hit a medium duty snowplow blade head-on which you then find medium duty truck was coasting at you in the opposite direction and so eventually you can reverse its direction. Can the pickup truck take this? Probably for awhile and depending on the mechanical inertia behind the truck. But you can see how it can shorten the life.

The thing saving the enterprise is the low amount of horsepower that a manual machine tool requires. But get to rated hp capacity and try that you will be buying a new VFD.

Yes, this is largely correct. We did that with a 1hp VFD on a 1hp brideport and it worked for a while. But later my dad killed it on another 1hp motor. The 5hp chinese ones will not hard start a 3hp motor. So that one gets ramped and the 1hp hard started. Basically my dad has VFDs setup like rotary phase converters. I think it's dumb but he's dead set on it.

 

[stioc]

A quick internal threading job on the lathe

 

[kazlx]

Nice job!

 

[stioc]

Thanks man! Being plastic it took all of 10 mins which included changing the gears for 12 TPI. Just took a spring pass to verify the thread pitch and then a full depth pass, done. No slop

 

[MushCreek]

I had to figure out how to hold three dimensional cast iron stars so I could drill and tap the back of them for mounting. I was building a folk art flag, so I needed a bunch of them! The shape doesn't lend itself to holding easily, so I made a simple fixture. I had a piece of aluminum with a 1" hole. I bored/faced an angle to match the starts, which are about 23 degrees. I put in three tapped holes, and was going to make a cover plate to hold it, but #10 screws with washers clamped it fine. I could only use two of the holes due to variations in the stars, but it held them nice and solid. Clamp it up, spot, drill, tap, and repeat. I could have made a much more sophisticated fixture at work, but in the barn, you use what you've got.

 

[larry4406]

I had to figure out how to hold three dimensional cast iron stars so I could drill and tap the back of them for mounting. I was building a folk art flag, so I needed a bunch of them! The shape doesn't lend itself to holding easily, so I made a simple fixture. I had a piece of aluminum with a 1" hole. I bored/faced an angle to match the starts, which are about 23 degrees. I put in three tapped holes, and was going to make a cover plate to hold it, but #10 screws with washers clamped it fine. I could only use two of the holes due to variations in the stars, but it held them nice and solid. Clamp it up, spot, drill, tap, and repeat. I could have made a much more sophisticated fixture at work, but in the barn, you use what you've got.

50 Stars for you!

 

[lis2323]

Good thinking, Mush. I prob would have broken them trying to clamp
them down on a D P table. Nice work!

 

[jeff g]

Hi
Only 45 stars on the flag ???

 

[MushCreek]

Good catch! The flag is made out of reclaimed lumber from a local textile mill, built in 1896. I wanted it to look as if it were made in 1896, when there were 45 states. I even de-zinced the screws, as they would have used plain steel hardware back then. The wood is left over from a batch I used to floor our house. Neat stuff, with lots of patina and scars.

 

[Bears Fan]

Okay that is just ******** coooooool

 

[KMScott]

Awesome work MushCreek.

 

[KBigg]

Heres something different for me. A local pontoon company had us make some 8” tow points and i had to drill and tap 2 8-32 holes in one end. Used the v block so i could do the 20 or so without sweeping each one in. The bottom has a .5” boss thats threaded 3/4-16 so i had to set it up on 1-2-3 blocks. A piece of 1/2-13 allthread hold its down, id say it worked out well.

 

[stioc]

^
Pretty cool! Not following how you milled it though; was it done on a 4-axis cnc mill?

 

[KBigg]

^
Pretty cool! Not following how you milled it though; was it done on a 4-axis cnc mill?

Noooo, everything except the holes I drilled and tapped was done on a cnc lathe. I could have done it in the 4th axis but it would have taken forever. It was just an odd setup I felt like sharing.

 

[stioc]

Noooo, everything except the holes I drilled and tapped was done on a cnc lathe. I could have done it in the 4th axis but it would have taken forever. It was just an odd setup I felt like sharing.

Ahh nice! I'm always curious how and what something was made on lol

 

[Threadkiller]

I made one of these fun captive nut puzzles the other day. Fun little project.

 

[zmotorsports]

I made one of these fun captive nut puzzles the other day. Fun little project.

Those are a fun little project. I made one for my son a few years back as a stocking stuffer. When he started his first job after college as a Mechanical Engineer he decided to put it on his desk in his office. He routinely tells me he gets a lot of people come into his office and play with it and most have no idea how it was made or works. I was surprised more people, especially in the aerospace industry, hadn't seen one before.

 

[Hephaestus29]

I like it.
Did you use studs in the stars then put a nut
and lock washer on the back of the board or?

 

[stioc]

I made one of these fun captive nut puzzles the other day. Fun little project.

Cool, I've seen a few over the years but never tried to make one myself. So what's the secret behind this one? The rod threads into one of the end pieces?

 

[MushCreek]

I like it.
Did you use studs in the stars then put a nut
and lock washer on the back of the board or?

Flat head machine screws.

 

[fartymarty]

So what's the secret behind this one? The rod threads into one of the end pieces?

 

[stioc]

 

[kazlx]

I like making them so the ends are like .010 larger than the threads on the nut. It drives people more crazy thinking it went over the ends.