Need some speed tips for getting a project done faster.

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shild
Posts: 62
Joined: Mon Jan 22, 2018 11:58 pm

Re: Need some speed tips for getting a project done faster.

Post by shild » Thu Feb 01, 2018 12:41 am

Greg_Lewis wrote:
Wed Jan 31, 2018 11:58 pm
shild wrote:
Wed Jan 31, 2018 11:21 pm

I'm still confused about when to throw away taps. To me a tap has always either been good or broken off. Do you mean the tap will have more drag when backing up?
Taps will get dull just like any cutting tool. Experience is the only real way to know when this has happened. Try to get a feel for the resistance you get when tapping a hole with a new tap. After so many holes, the resistance will increase and at some point it just feels like it is too much. You just have to develop a sense for this; there is no hard and fast guideline. Taps should be considered a consumable item, not a one-time purchase. Better to toss a tap a little early than to break one in a part. (Taps only break off when you're doing the last hole at the end of three days of work on a complicated and expensive casting :( . It is guaranteed that they will be jammed tight in the hole and resist all efforts at removal. )
You mean like a cylinder casting? By the way, last time I broke a tap I had just finished tapping the hole and was doing a fast rapid out with a tap wrench which might have been too big for it and wasn't balanced well for that particular size. :x Only lost the tap though, came right out with pliers. :)

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Builder01
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Re: Need some speed tips for getting a project done faster.

Post by Builder01 » Thu Feb 01, 2018 5:39 am

Hi Shild,

My 0-6-0 is a coal burner. Even though it is a small locomotive, it steams quite well.

As for screws rattling out, I suppose it is possible, but, it has never happened over the past year during the running season.

Counter balances on machine hand wheels? I can't imagine ever turning a hand wheel fast enough to make that a requirement, even when backing away from something!!

As for counter balances on miniature loco wheels, it is mostly for appearance. There is not really enough weight in the running gear to make this important. Especially at 1" scale. But, yes, many folks add weights if the casting does not have them cast in. It just looks more proper that way.

David

RET
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Re: Need some speed tips for getting a project done faster.

Post by RET » Thu Feb 01, 2018 10:21 am

Hi,

There is such a thing as being in too much of a hurry. I always tap by hand, never under power. That way I have better control over things. Under power, by the time you realize what has happened, its too late and you don't begin to have the same "feel."

Remember, ninety nine percent of the time it isn't the torque that breaks the tap, its because you have applied a bending load to it. If you think about it, its because the sharp root of the thread is a stress concentrator. From that standpoint, Whitworth threads would be better because they have a rounded root and peak (used in England).

Unless you are careless, you should never break a tap 1/4"-20 or bigger and even the little ones very seldom. If you do break one off (especially in a blind hole in a part you have invested a lot of time/money in) you can get the broken piece out by using a diamond burr in a Dremel. For the little burrs, ask your dentist for his cast off ones. The process is slow, but it works, I've done it and it certainly beats making a new part.

I find that when I'm tapping small holes (#0-80 or larger) it is better to hold both the part and the tap and the tap wrench in my hands. I have much better control that way. See the Big Boy thread (making the power reverse).

Joining a group and learning from others is a VERY good way of learning. You will find that everyone has a different area of expertise and you never know which person is going to give you that one priceless piece of information that makes all the difference. After a while you will find that you know enough that you can start giving back to others (what goes around, comes around).

There's always more, but this will do for now.

Richard Trounce.

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NP317
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Re: Need some speed tips for getting a project done faster.

Post by NP317 » Thu Feb 01, 2018 11:10 am

I was recently tapping very small holes (00-80 and 00-90) in brass.
I found the safest method was to hold up the part being tapped, with the tap handle hanging vertically down under it.
This prevented gravity from applying sideways forces, eliminating tap breakage. And I've used this "float" method for larger thread sizes too.
Another advantage: The chips can fall out of the hole during tapping, unless tap lube was used.
Mostly applied to larger holes than micro. I can't even see those 00-90 threads without magnification!
~RN

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SteveM
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Re: Need some speed tips for getting a project done faster.

Post by SteveM » Thu Feb 01, 2018 2:57 pm

NP317 wrote:
Thu Feb 01, 2018 11:10 am
I found the safest method was to hold up the part being tapped, with the tap handle hanging vertically down under it.
This prevented gravity from applying sideways forces, eliminating tap breakage.
Gravity, it's not just a good idea, it's the law!

I have a shop-made tapper that has an arm that reaches over the work, and a long tap extension in it. As long as everything lines up correctly, it should reduce tap breakage, although I have not yet had the pleasure of tapping 0-80 holes yet.

We will find out.

Steve

tornitore45
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Re: Need some speed tips for getting a project done faster.

Post by tornitore45 » Thu Feb 01, 2018 3:17 pm

Counter balances on machine hand wheels? I can't imagine ever turning a hand wheel fast enough to make that a requirement, even when backing away from something!!
Is not for balanced spinning like in a car wheel, is to prevent vibrations to cause rotation of the wheel/dial.

Handle-Hub-Large-Ball-counterbalancing-the-Handle
Mauro Gaetano
in Austin TX

Kimball McGinley
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Re: Need some speed tips for getting a project done faster.

Post by Kimball McGinley » Thu Feb 01, 2018 3:36 pm

I love RET's 4-5-40 and 6-8-10-32 trick. BLOODY BRILLIANT!

Another thing; an experienced machinist once told me that he avoids using 6-32 screws like the plague, he pointed out with the 10,8, and 6-32 all sharing the same depth of thread, the center "core" on a 6-32 is exceedingly fragile and those taps consequently break off easily. This came after I successfully tapped 11 of 12 6-32 holes in my 6" 302 stainless pipe smokebox. It is still in there, I just glued in a fake screw at that location...

Kimball McGinley
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Re: Need some speed tips for getting a project done faster.

Post by Kimball McGinley » Thu Feb 01, 2018 3:51 pm

Oh, and always try to tap in the mill or drillpress, avoid "freehand" tapping. When it starts crooked, it is more likely to jam and break.

I made set of small guide blocks (on the lathe from round bars about 1' diameter or so) to guide the tap straight for better freehand tapping off the machine. Just get it in a few threads and then remove it. You can counter-drill them a bit at the bottom for some chip clearance. A countersink in the top will help your cutting fluid get in there.

Your tailstock drill chuck should have no trouble gripping a tap; there must be something wrong there?

When I tap in the lathe, I too use the switch, but I partially eject the chuck from the tailstock by backing off on the handwheel. At that point, it is held on center, but spins freely. I then engage the tap and "brake" it from spinning with my right hand. When it starts to get too tight, I just release it and let it spin, then stop the lathe with the switch.

Yeah, you really don't want to "plug" the motor too often, that is the term for immediately reversing the motor while running at speed. It is hard on everything...

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Builder01
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Re: Need some speed tips for getting a project done faster.

Post by Builder01 » Thu Feb 01, 2018 4:10 pm

tornitore45 wrote:
Thu Feb 01, 2018 3:17 pm
Counter balances on machine hand wheels? I can't imagine ever turning a hand wheel fast enough to make that a requirement, even when backing away from something!!
Is not for balanced spinning like in a car wheel, is to prevent vibrations to cause rotation of the wheel/dial.

Handle-Hub-Large-Ball-counterbalancing-the-Handle
"prevent vibrations to cause rotation of the wheel/dial"

What does this mean?

David

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Greg_Lewis
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Re: Need some speed tips for getting a project done faster.

Post by Greg_Lewis » Thu Feb 01, 2018 4:25 pm

For the 00-90 and 0-80 taps, I use a pin vise to hold the tap. More sensitive feedback, and since you are turning the tap by the small diameter of the pin vise compared to the relatively large tap wrench, less chance of breakage.
Greg Lewis, Prop.
Eyeball Engineering — Home of non-interchangeable parts.
Our motto: "That looks about right."
Celebrating 30 years of turning perfectly good metal into bits of useless scrap.

Pontiacguy1
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Re: Need some speed tips for getting a project done faster.

Post by Pontiacguy1 » Thu Feb 01, 2018 5:03 pm

I found a junky old drill that no longer worked, but had a really nice and small 1/4" drill chuck on it. that drill chuck is perfect for holding smaller taps and turning them. It also had a short 3/8" stem on it, about 3/4" long, so it can be chucked in the mill if need be. That thing has done very well for me tapping small holes. I never use it on anything larger than #8, and since it is not big in diameter, you can feel if the tap is dragging or sticking.

My father-in-law was a tool and die maker for 30+ years, and also said that he avoided using #6-32 threaded holes and bolts for the exact same reasons mentioned above. For the size, it is a really coarse thread and takes a lot of power to tap for such a small root diameter. Thus, they are a lot more prone to breakage than any other size around it. He always either went down and used a #5-40, or up and used a #8-32.

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Fender
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Re: Need some speed tips for getting a project done faster.

Post by Fender » Thu Feb 01, 2018 5:25 pm

If you have a lot of non-critical holes to tap (for example, in sheet metal) use a cordless drill to do the tapping. Set the clutch so it slips when the tap meets resistance, then quickly reverse the drill to clear the chips and run forward again. I find that this is faster and less likely to break a tap than hand tapping.
Dan Watson

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