Monitor Steam Engine

[crueby]

Love the crayons - is there a chapter in the Machinists Handbook on proper colors to use for different materials, tap vs clearance drilling, that sort of thing?!   

Goes with this plaque:

[Kim]

Marv...I don't know 'buchstaubiern'. That seems to translate to 'paper jam beers'?
Swapping the 'i' and 'e' gets me 'paper dust Irish'.

Zee,
I don't know German, but I used Google Translate and it gave me this:

"lassen wir richtig buchstaubieren" = "can we spell correctly"

Kim

[Flyboy Jim]

Karl (lassen wir richtig buchstaubieren),

Yes, you need to watch what you're doing and move the quill down when the tap wrench is about to escape from the guide pin.  I have a tap wrench like yours and find it way too heavy for small taps.  For those you need something with low inertia so you don't lose your tactile feel for what the tap is doing.  With my small tap holders I can always feel when I've outrun the guide pin.

Jim,


There's a program on my page, DRILL, which will compute tap drill sizes for conventional and form taps as well as other good stuff.  But, briefly,

TD = tapdrill size
MD = thread major diameter
P = thread pitch (tpi)
DOT = desired depth of thread expressed as a percentage

then

TD = MD = 0.013*DOT/P

Example: 1/4-20 thread with DOT = 55%

TD = 0.25 - 0.013*55/20 = 0.2143  which implies a #3 drill

Here are some suggested DOTs for various materials


MILD AND UNTREATED STEELS                       60-65
HIGH CARBON STEEL                                         50
HIGH SPEED STEEL                                             55
STAINLESS STEEL                                                50
FREE CUTTING STAINLESS STEEL                     60
CAST IRON                                                          70-75
WROUGHT ALUMINUM                                    65
CAST ALUMINUM                                              75
WROUGHT COPPER                                           60
FREE CUTTING YELLOW BRASS                       70
DRAWN BRASS                                                   65
MANGANESE BRONZE                                      55
MONEL METAL                                                   55-60
NICKEL SILVER (GERMAN SILVER)                   50-60


Stan,

Love it.  Trouble is, if Starrett sold crayons, they'd cost $20 apiece.  Mitutoyo crayons would cost $1 and last three times as long.

Thanks Marv,

I got it printed out and headed for my notebook.

It looks like, using my 5-40 example, that I could use a #37 (0.1040) for a 65% thread depth. My chart (Sherline) showed the #38 (0.1015) that I listed in my example. Should tap a lot easier with the #37 hole!

Jim

[fcheslop]

A future project maybe
http://mikesworkshop.weebly.com/a-spark-erosion-apparatus.html
Make a tapping stand saves mucking about like a one handed fan dancer
Need some of those Hayes cranked bolts.Do you have a link
Good luck
cheers

[zeeprogrammer]

Nice chart Chris.
Seems like I've made one or two of those.

Kim...thanks. It was the 2nd 'u'.
buchstabieren = spell
buchstaubieren = paper jam beers

I don't know if it's a dialect thing...or 'gasp'...Marv spelled it wrong.
Or maybe he's using an 'older' German. 

I had similar problems when we came back stateside from Germany. My new German teacher and I had trouble understanding each other.
I was using a Bavarian dialect.
I wish I had gotten good at it. Shame too as my mother is German, raised south of Munich and lived in Munich during the war.

In any case, your post scared me and I went running off to see where I'd misspelled something. All I could find was a missing 'to'. 

[zeeprogrammer]

Jim,
My chart shows #38 for 5-40 and #37 for 5-44 for 75% thread in aluminum.
If you use the #37, let me know how it goes.

Frazer,
I've wondered about a tap stand. Up to now I've always (or think I've always) simply swapped out the drill chuck and tapped without moving the part.
It would be faster I think to drill everything and then move to a tap stand.
My concern is finding the center of the hole again.
Is it okay to be a little off so long as the tap is straight?

[crueby]

Friend of mine spent a year in Germany during his high school years, and he flunked English, teacher learned in England decades before and all the dialect/regional/translation differences tripped him up. When I was in school we had an exchange student from Mexico City, he spoke English very well, but one teacher was from West Virginia, they could not understand each other's accents at all.

[fcheslop]

Maybe not faster you just get a better feel
Never had a problem re centring using a 2nd tap then a bottoming tap
I do  often start the tap in the mill then move the job onto the little tapping stand I have. Although its to small for the current toy Im struggling with. Most of my stuff is small as in M3 is huge
Just the way I do things and we all have our own little peculiar ways . What ever works for you.
I keep looking at that wee spark eroder usually after breaking a tap
cheers

[zeeprogrammer]

I have several UK friends. If I haven't been around them for long it usually takes a little while to start understanding.
Interestingly, one person I've had the hardest time with is Don. Strong, interesting accent/dialect.
So Don, if you find me looking at you in a puzzling manner...I'm just trying to figure out what you said. (And if it's something nice or a poke at me  )

[PStechPaul]

You might want to try a spring-loaded tap guide. I have one but I haven't used it yet. It fits in a drill chuck or collet and the plunger is reversible so it will fit a tap holder with an indented center hole using a point, or the pointed end of a tap using an indented center.
http://littlemachineshop.com/products/product_view.php?ProductID=1963&category=



You might also try clamping a weight on the quill handle so that it exerts a constant force on the tap, and so it will follow it as it goes into the tapped hole.

[zeeprogrammer]

So let's talk drill bits.
Drill sets are nice to start with but I find I don't use most of them and I question their quality.
I'm inclined to look for individual bits.

Different bits for different jobs. What I'm talking about is generally 1/4" or smaller, mainly for tapping (but also clearance).
I think I'm talking about 'jobber' bits.
Different coatings, material, and drill point.

Let's start with drill point. Seems to be either 118 or 135.
When would one choose one over the other?
118 seems like a good idea for blind holes.

Material...hm...HSS, cobalt, carbide.
Cobalt seems pricey for what I want to do.
What are the thoughts on HSS vs carbide?

Coating...there's several but it looks like choices are black oxide, bright, and TiN.
I notice all my end-mills are TiN.
I'm thinking TiN is harder/better than black oxide. I don't know about 'bright'.

So pile in. I'm looking to learn.
More fun than googling and still left wondering.
Here I get more direct experience in the kind of work/play we do.

[b.lindsey]

Production use is one thing, hobby use is another. For my money, quality (name brand be it USA, UK or wherever) is more important than the other factors, especially for the light use most of us give them. I have always used 118 degree, black oxide but from names like Hertel or Cleveland Twist Drill, etc.  Now if we were using more exotic materials it would be a different matter, but for brass, aluminum, and mild steels these have worked well for me.

Bill

[fcheslop]

As per Bill with the proviso Learn how to sharpen them
Stay away from cheap chinky stuff they will only snap in that important hole and the same with taps,reamer.
I recently bought some  metric reamers of unkown origin and the bushes ended up like a backside on a pot
cheers

[mklotz]

Most drill charts ignore DOT and size the tap drill according to the simplified formula

TD = MD - 1/P

Thus they are assuming that

0.013*DOT = 1

or

DOT = 1/0.013 = 77 %

so using the drill in the table will give you about 77 % DOT, which is a bit more than most threads need.  Tapping becomes much easier by making this percentage a bit smaller.

Since metric threads are also 60 deg threads, this formula can be used for them.  Since metric pitch is already in the form of a length/thread (as opposed to TPI = threads/length), the formula then becomes

TD = MD - 0.013*DOT*PM

where

PM = metric pitch.

[sshire]

Zee
On Bobsmodels recommendation, I ordered an assortment of Precision Twist Drills in my most used drill sizes. Astounding. The difference between those and my original Horrible Freight set is very noticeable.
As I need to replace, I'll get the PTD.
ENCO