What is a "sensitive drill press" and is it useful in a home machine shop?

HMF

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How does a "sensitive drill press" differ from an ordinary drill press.

Is it a necessary piece of equipment in a home shop?

What types of tasks are best done on a 'sensitive drill press"?

Thanks!


:tiphat:
Nelson
 
I didn't know I had a sensitive drill press in my shop till I was commenting on its lack of throat depth and it got hurt feelings and refused to drill anything. :nuts:

OK sorry for the bad attempt at a joke. I think a sensitive drill press is any drill that you can feel the pressure you are applying to the cutter during operation. So most of our drill presses fit this. However there is also what I have heard called a sensitive drill chuck. http://www.use-enco.com/CGI/INSRIT?PARTPG=INLMKD&PMPXNO=952920&PMAKA=290-1292

I
have one of these and it is great for drilling very small holes (less than #50 for example) I drill circuit boards often on my mill and I could not do it without one of these.

Jeff
 
A quick google came up with this:

This machine is generally used for moderate-to-light duty work. The upright sensitive drill press gets its name due to the fact that the machine can only be hand fed. Hand feeding the tool into the workpiece allows the operator to "feel" the cutting action of the tool. The sensitive drill press is manufactured in a floor style or a bench style.

So pretty much all of our drill presses fall into this category.

Andrew
 
A regular drill press does in my mind not qualify as a sensitive drill press. Have you ever tried drilling a #64 bit in steel with your regular drill press. You know what is going to happen don't you. The bit is going to break before you really get started. Even around 1/16" you will not be able to feel the drill bit cutting. For drilling below 1/16" you need much more speed than our regular drill press can provide. So, I switch to my small drill press, about 8" swing and much finer quill feed for most drilling below 1/8". This little machine also has a much higher speed range required when drilling small diameters. Although it does have about a 3/8" or 1/2" chuck it would be useless for that size drilling in metal. Speeds start too high.
However when you add the sensitive chuck as mentioned before you now have a sensitive drill press. You no longer use the quill feed but a finger feed. The chuck has two shafts inside each other. The smaller inner shaft has a small keyway the full length and the outer shaft, the part that chucks into your drill press chuck has a small key in a slot held in by a thin spring ring half way up the shaft. This makes for a telescopic shaft. The inner shaft which is spring loaded holds the small chuck and above it rides a knurled disc with a bearing in it.
In use you hold the disc between two fingers and then you can gently pull the chuck down and then you can feel the tiny drill bit cutting.
Illustrations below.

P1030360.JPG P1030362.JPG P1030365.JPG

Another kind of sensitive drill press was made by Dremel Moto Tool. It held your standard Dremel moto tool with a chuck on it. Here you raise the table via a knob operating a cam under the table giving you the same sensitivity as the chuck above did.

P1030367.JPG P1030366.JPG
I hope this helps, Nick

p/s
In the previous mention of this chuck it shows a price of around $270.00. WOW. I use to sell it without the chuck for around $70.00 and a precision Jackobs chuck ran around $100.00

P1030362.JPG P1030360.JPG P1030365.JPG P1030367.JPG P1030366.JPG
 
p/s
In the previous mention of this chuck it shows a price of around $270.00. WOW. I use to sell it without the chuck for around $70.00 and a precision Jackobs chuck ran around $100.00

Yea, I didn't even look at the price when I posted that sorry. Mainly was just going for an example of one. I think I paid less than $50 for a used one. With my fingers that close to a high speed shaft I do not recommend going cheep. The one I have is VERY smooth.

Oh just found this one on Enco http://www.use-enco.com/CGI/INSRIT?PARTPG=INLMKD&PMPXNO=951000&PMAKA=290-1291 Looks OK would have to use one to be sure. The price is much better.

Jeff
 
With my fingers that close to a high speed shaft I do not recommend going cheep.
True that!

The other thing is, as easy as it is to snap these little micro drill bits a quality tool pays off in spades.

74drillbit.jpg

74drillbit.jpg

74drillbit.jpg
 
Those are good for small drilling, but be careful chucking them up. If you gorilla the chuck key, you can egg the outer shell and it won't slide out as easily as it should.
 
A regular drill press does in my mind not qualify as a sensitive drill press. Have you ever tried drilling a #64 bit in steel with your regular drill press. You know what is going to happen don't you. The bit is going to break before you really get started. Even around 1/16" you will not be able to feel the drill bit cutting. For drilling below 1/16" you need much more speed than our regular drill press can provide. So, I switch to my small drill press, about 8" swing and much finer quill feed for most drilling below 1/8". This little machine also has a much higher speed range required when drilling small diameters. Although it does have about a 3/8" or 1/2" chuck it would be useless for that size drilling in metal. Speeds start too high.
However when you add the sensitive chuck as mentioned before you now have a sensitive drill press. You no longer use the quill feed but a finger feed. The chuck has two shafts inside each other. The smaller inner shaft has a small keyway the full length and the outer shaft, the part that chucks into your drill press chuck has a small key in a slot held in by a thin spring ring half way up the shaft. This makes for a telescopic shaft. The inner shaft which is spring loaded holds the small chuck and above it rides a knurled disc with a bearing in it.
In use you hold the disc between two fingers and then you can gently pull the chuck down and then you can feel the tiny drill bit cutting.
Illustrations below.

View attachment 29823 View attachment 29822 View attachment 29824

Another kind of sensitive drill press was made by Dremel Moto Tool. It held your standard Dremel moto tool with a chuck on it. Here you raise the table via a knob operating a cam under the table giving you the same sensitivity as the chuck above did.

View attachment 29825 View attachment 29826
I hope this helps, Nick

p/s
In the previous mention of this chuck it shows a price of around $270.00. WOW. I use to sell it without the chuck for around $70.00 and a precision Jackobs chuck ran around $100.00


Followup stupid question, Nick (yes, I do read you guys' responses), so what is the operative difference between a nice ENCO drill press (which I have from 30 years ago) with an Albrecht sensitive chuck attachment and a stand alone sensitive press?


Nelson
 
This is what I think of when talking about a sensitive drill press: http://www.artcotools.com/dumore-16-021-series-16-sensitive-drill-press-pr-18318.html

The major differences being the size, the speed of the spindle, and the amount of force used to feed the work into the drill bit or vice versa.

Smaller in stature than the average bench mount drill press.
Much higher RPM that really small drill bits require to obtain the proper SFM needed.
And no heavy quill return spring to fight against, giving you a much better feel for how much pressure is actually being applied to the drill bit.

I would say the spindle speed is the most important difference though. :footinmouth:
 
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