Author Topic: Sensitive Drill Attachment  (Read 3485 times)

Offline JasonP

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Sensitive Drill Attachment
« on: September 06, 2022, 07:13:10 PM »
After spending a productive weekend reading build logs for the MEM Corliss, I came across a discussion of a sensitive drill attachment. I'm new to the machining game and hadn't heard of this before, to my cost. When I was machining the engine block for my corliss I broke 3 drills trying to drill the steam ports, which caused no end of grief. It doesn't help that I'm using a bit of 1018 scrap that is quite "grabby".

So after a bit of research I hit ebay and found what I think is a nice tool, a Jacobs #0 chuck and #55 Drill attachment. It's now on it's way to me, but I'm a bit wary as it is used. Does anyone know how to evaluate how good this tool is? Where should I be concerned?  Any advise on this tool and it's use would be greatly appreciated.

Jason

Offline crueby

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Re: Sensitive Drill Attachment
« Reply #1 on: September 06, 2022, 07:29:29 PM »
I don't have much experience with a senstive drilling attachment, but have vowed to never again use 304 stainless steel, it also is very grabby and work-hardens quickly, destroyed a number of drills and taps on that. Some alloys are just not worth the trouble on models.


1018 steel is rated low for machining, though it is very popular for welding.  I much prefer using 303 stainless, it machines very well, does not work harden, drills and taps very well. Not available in as many shapes/sizes, but worth looking at if you can.

Offline steamer

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Re: Sensitive Drill Attachment
« Reply #2 on: September 06, 2022, 08:58:01 PM »
If its' not getting wet on a regular basis,  consider 1144SP.   It's a low alloy medium carbon steel, with excellent properties ( 100,000 psi yield ect) but is very nice to machine, drills, mills and taps very well, and is fine without heat treat, though you can case harden it very well.    good stuff!

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline TerryWerm

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Re: Sensitive Drill Attachment
« Reply #3 on: September 06, 2022, 10:16:02 PM »
Can you tell us a bit more about the #55 drill attachment? 

Sensitive drills usually require a couple of things:
1. High speed. Spindle speed in the neighborhood of 10,000 RPM or even higher work the best for these tiny drill bits.
2. The ability to hold the bit nice and square to the work
3. The ability to advance the drill bit with light pressure. They often have a bearing mounted collar on the spindle that you hold with two fingers in place of a rack and pinion with a long handle. You don't need much pressure.

The reason a sensitive drill press has that name is because using your fingers to advance the spindle allows you to feel what the tiny bit is doing in a very sensitive fashion. If the flutes of a tiny bit are starting to fill up with chips, you will feel it in your fingers long before you hear it in your ears. With some of the very tiny bits the bit will break before you ever hear things binding up.
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Terry
Making chips when I can!

Offline steamer

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Re: Sensitive Drill Attachment
« Reply #4 on: September 06, 2022, 10:40:04 PM »
As Terry has described you need "feeeeel"    about 20 years ago, I made a sensitive drill attachment on my lathe.   It consisted of a MT3 blank arbor bored in the lathe it was going to be used in.   I bored it to fit (2)  1/2ID   x 3/4" long drill bushings.    I then got a straight shank drill chuck arbor with a jacobs taper to match a nice albrecht chuck that I had.     The shank fits very closely in the bushings.   I drilled a vent hole for the air to escape.    and you are done!

Later Joe PI published this video....and wouldn't you know it...

<a href="https://www.youtube.com/watch?v=PqU5wS0J4MU" target="_blank">http://www.youtube.com/watch?v=PqU5wS0J4MU</a>

I can't say i invented this, but I doubt Joe did either.    I will say it works awesome!   and as soon as you feel that drill do anything other than cut...just let go...stop the lathe ,and back the drill out.   works great!

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline steamer

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Re: Sensitive Drill Attachment
« Reply #5 on: September 06, 2022, 11:09:30 PM »
Now if you want to drill REALLY small...   ( 0.0039" drill)    You need to control the feed of the drill   You're hand isn't good enough.  What happens is the drill grabs and tries to pull in and you break it immediately.   I built a rig that Jerry Kieffer described for my Levin.    And I want to say it worked awesome

To do this on a WW lathe, you make a new TS quill with a 40TPI thread on the back half.   Add to this a 3" diameter nut.   The way it works is you slowly screw the nut such that it lets the drill advance, but won't let it grab and pull it in.    It worked great!   

<a href="https://www.youtube.com/watch?v=4DFuSwGvX1A" target="_blank">http://www.youtube.com/watch?v=4DFuSwGvX1A</a>

and a picture of the rig below...with a big but very thin and delicate brass nut on a 3125 x 40 thread.

I use 1/8 shank PC drills     The part in the video is 5mm OD with a 0.1mm diameter drill.   The material is 12L14 steel.

Speed was somewhere around 3000 rpm.   No you don't have to be spinning any faster than that....yes it does work.

Dave


Here's the article that Jerry wrote on the subject...

https://mb.nawcc.org/threads/safe-and-accurate-micro-drilling-on-a-watchmakers-lathe.150255/



« Last Edit: September 06, 2022, 11:20:07 PM by steamer »
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Offline steamer

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Re: Sensitive Drill Attachment
« Reply #6 on: September 06, 2022, 11:25:02 PM »
I will be making an attachment for my Collet TS that is very similar, for the same reasons
"Mister M'Andrew, don't you think steam spoils romance at sea?"
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Offline mklotz

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Re: Sensitive Drill Attachment
« Reply #7 on: September 07, 2022, 12:00:03 AM »
Micro drilling requires "feel", the mechanical feedback one gets when drilling.  Unless you're willing to spend big bucks, amateurs seldom have equipment that can supply that feel.  One approach is to build a very lightweight mechanism that can apply the work to a drill held stationary in whatever spins it - a sensitive table.

Adapting from an article in one of the mags, here's what I built...

https://www.homemadetools.net/forum/sensitive-drilling-platform-60287#post91042
Regards, Marv
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Offline steamer

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Re: Sensitive Drill Attachment
« Reply #8 on: September 07, 2022, 12:06:21 AM »
I can only speak to what Jerry has done, and what I copied.    It worked fine Marv.

Dave


"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline steamer

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Re: Sensitive Drill Attachment
« Reply #9 on: September 07, 2022, 12:07:59 AM »
If you read the micro drill attachment description, it directly indicates that you need to control the feed, and not bottom out on the hole.    All of which Jerry describes in his article.

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline steamer

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Re: Sensitive Drill Attachment
« Reply #10 on: September 07, 2022, 12:10:39 AM »
Love to talk to you Marv..

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline JasonP

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Re: Sensitive Drill Attachment
« Reply #11 on: September 07, 2022, 12:31:20 AM »
Thanks All. Interesting points all.
I was just using a bit of steel I had on the shelf that was dimensionally close. Now I know how horrible it is it's getting tossed. I've used 12L14 - lovely stuff - if I can find it in the size I need, 4130, 4140 but that's a bit tough. I was trying to make a 4" adapter plate out of 4130 when I fried my lathe motor.... I'll take a look at the 1144SP and see if it's available.
10,000 RPM is a bit excessive for my machines! 2500RPM is my limit on the mill. This will be a learning curve.
I don't know anything about the #55. I assume it's a discontinued model, but I'll find out when I get my hands on it and report back.
I did see Joe Pie's video after I discovered the posts about the attachment. I would have made one and gone down that road, but I need it on the mill.
0.1mm is ridiculously small! I could barely see that without a microscope, let alone try to drill it!

Offline steamer

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Re: Sensitive Drill Attachment
« Reply #12 on: September 07, 2022, 01:18:44 AM »
Thanks All. Interesting points all.
I was just using a bit of steel I had on the shelf that was dimensionally close. Now I know how horrible it is it's getting tossed. I've used 12L14 - lovely stuff - if I can find it in the size I need, 4130, 4140 but that's a bit tough. I was trying to make a 4" adapter plate out of 4130 when I fried my lathe motor.... I'll take a look at the 1144SP and see if it's available.
10,000 RPM is a bit excessive for my machines! 2500RPM is my limit on the mill. This will be a learning curve.
I don't know anything about the #55. I assume it's a discontinued model, but I'll find out when I get my hands on it and report back.
I did see Joe Pie's video after I discovered the posts about the attachment. I would have made one and gone down that road, but I need it on the mill.
0.1mm is ridiculously small! I could barely see that without a microscope, let alone try to drill it!

That video was done under a USB microscope.   I can't see it any other way!!

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline TerryWerm

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Re: Sensitive Drill Attachment
« Reply #13 on: September 07, 2022, 01:29:36 AM »
Sorry guys, the part where I said 10,000 RPM was meant to be 1,000 and up, and I failed to proofread it before I posted. Not sure if it was just a brain fart or what, as it has been an exceptionally rough day today.

I have a sensitive drill press with a stationary spindle. The table moves up and down and is spring loaded. The spring is adjusted so that it helps to lift the weight of the table, it acts as something of a counterbalance. It is easily adjusted to lift more or less as needed. It has a single speed spindle that runs in the neighborhood of 2500 RPM. The knob that lifts the table has better feel than one might think.
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Terry
Making chips when I can!

Offline steamer

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Re: Sensitive Drill Attachment
« Reply #14 on: September 07, 2022, 01:33:32 AM »
Nice drill press     Is that a home built?

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

 

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