Mini Bench Drill Press

[Chuck Seiler]

Bob,

 

    Agree with all.  I may check with Larry to see what collar options he has.  Alternatively, I may just mount my older corded Dremel (I recently found while cleaning) that is symmetric.  But, since one can never have too many tools, I am still eyeing the set--up Gregory is trying out.

[Roger Pellett]

My current modeling project has recently required me to drill 100’s of small holes (.010”- .025”) in brass.  I am fortunate to own a well equipped Sherline lathe and milling column.  My Sherline tool kit includes a sensitive drilling attachment. Using this fitted with a sharp HSS drill bit, I can drill holes in brass like it’s butter.

 

Structurally, drill bits are columns. These small drill bits are very slender columns.  When subjected to axial loads, columns fail by buckling.  If the load is not truly axial, (the load does not pass down the longitudinal center of the column) even less load is required for the column to fail.

 

So, how does this theory effect us?  First, any force in excess of that actually required for the drill to cut can cause the bit to buckle and fail.  Second, anything that results in an eccentric load will dramatically reduce the drilling force leading to failure.  This latter could either be caused by the center punch not being correctly lined up beneath the drill chuck or by the drill bit skating when trying to drill without first center punching.

 

Structural theory would, therefore, indicate that these micro drill presses could be blind alley.  While an x-y table can allow proper alignment of the drill bit with the work piece, the mechanical advantage of the lever actuated quill does not give one the sensitive feel needed when using tiny bits.

 

While I realize that many do not want to Spend 1000++ for a Sherline mill and accessories, a better option might be one of the full sized house brand drill presses now sold by home improvement stores, and fitted with an x-y table and separate sensitive drilling attachment.

 

Roger

[Gregory]

I Have a  full sized house brand drill press outside in my workshop where my other full sized tools are.

 

I don't want to take my model work outside, bring my full sized tools into my relatively small modeling area, nor re-configure my full sized tools to work on a one-off modeling project.

Still, I guess it remains an option.

 

Edited February 4 by Gregory

[oakheart]

5 hours ago, Roger Pellett said:

when trying to drill without first center punching.

Hi roger @Roger Pellett I have taken to using a tiny centre drill, then using stub drills for small sized holes.
Unfortunately, they are not as available in the sub 1mm sizes, a pre drilled guide block can help here, even when made from a relatively soft material like a close grain wood or perspex.

 

Tim

 

Edit : I just found these:-

 

0.5mm centre drill £11

https://www.shop-apt.co.uk/centre-drills-60-altin-coated-carbide-high-quality-45hrc/centre-drills-05mm-x-60-point-3mm-shank-altin-coated-carbide.html

 

0.5mm stub drill  $18

https://www.maritool.com/Cutting-Tools-Drills-Powdered-Metal-Drills-Micro-(.5-1.9mm)-Nachi-Powdered-Metal-Drills/c78_140_1576_1579/p25040/Powdered-Metal-Stub-Length-Micro-Drill-.0197-dia-(.50mm)-SG-Coated/product_info.html

 

are these cost effective in our hobby environment?

 

Edited February 4 by oakheart

[wefalck]

I think a lever as such is not the problem when using sub-millimetre drills, but rather the position of the arm when using the lever. You have to be able to rest the arm on the table as much as possible, perhaps working only from the wrist in order to reduce the number of degrees of freedom you have to control.

 

In the watchmaking etc. industries they have used such drill-presses for something like 150 years now:

The preferred brand of Jacobs-chuck there is 'Albrecht', but they are ridicously expensive (we talk about several hundred €/US$/£ when new). The above machine used horological collets, but a less expensive option is to use ER7 or ER11 collets for which arbors are available to screw on in place of a drill-chuck.

 

There HSS sub-millimeter drill-bits on the market that have 1 mm shafts. Their spiral is in order of 5x the diametre long, so they are relatively stiff and do not wander. I use a carbide scriber as centre punch to locate holes.

 

I have not had a chance to closely inspect any of these small drill-presses that sparked off this thread, but think they could be a useful tool, perhaps with some upgrading to ensure no play in the mechanical parts.

 

[Thukydides]

11 hours ago, Gregory said:

 

I don't want to take my model work outside, bring my full sized tools into my relatively small modeling area, nor re-configure my full sized tools to work on a one-off modeling project.

Still, I guess it remains an option.

This is my problem, my workshop is my bedroom or (if I am generating much sawdust) my kitchen table. So I have almost no room for any large tools. So I am always interested in small things like this that will potentially enable me to at least be more accurate and speedy than using my hand held pin vice.

[Roger Pellett]

Many, many years ago a dentist gave me a handful of steel dentist burrs.  They have sat in a 35mm film can ever since.  These have a 3/32” shaft with a “snout” tapering to a ball shaped cutting head.

 

 I recently found it necessary to drill a series #75 of holes through a piece of 1/16” diameter brass tubing.  I first filed a narrow flat along the top of the tube.  I have been unable to find a center punch with a really tiny point so ground one on the end of a piece of piano wire but actually using it fell short.

 

I then dug out my dentist burrs and found a really tiny one.  Chucked in my sensitive drilling attachment this did a great job in a accurately grinding a tiny depression at each location.  The job was then easily finished with a conventional HSS twist drill.

 

Roger

[Gregory]

Well, the mini drill press is a little more of a beast now.

 

I used some scrap melamine to elevate the drill and the X-Y table  a net of a little over 2 inches.

The little X-Y table is surprisingly well made considering the price.  It seems very stable but doesn't  have the precision that serious milling would require.

I could have done without the rotary table, but it will add a little more versatility should the need arise.

They do have a similar table on amazon without the rotary function at essentially the same price..

 

I discovered that the fixed part of the head has a threaded hole with which you can use a screw to fix the Z depth for milling.

 

I don't really have any jobs to do right now, but I feel like I have my micro drilling needs well covered as they come up.

 

I will do my best to answer any questions or try your suggestions.

It wouldn't surprise me if some of you could come up with a little more sophisticated configuration than I have managed. 

[grsjax]

The specs on some of these micro drill presses states that the shaft turns in a brass sleeve rather than bearings.  Should be ok for light work but I don't see anyway to lube the sleeve so for anything serious I would be a little worried.

[wefalck]

Are you sure it’s the spindle and not the guiding sleeves for the up and down movement?

[Gregory]

40 minutes ago, grsjax said:

Should be ok for light work

It's not really intended for anything but light work.

 

The head moves up and down as smooth as can be.  The spindle and motor are very quiet.  I believe the spindle uses some type of roller or ball bearings.

Is their any way to tell without taking it apart?

[Chuck Seiler]

Were you able to determine if the vertical post could be removed/replaced?

[wefalck]

I would be surprised, if the spindle used anything else than ball-bearings. Ideally there should be three: two radial ones and a third axial one to take up the force from drilling. The seats can be easily machined on a CNC mill. There would need to be a sleeve on the spindle to take up end-thrust. All in all the parts would cost only a few €/US$/£ … no point to mess around with brass bearings.

Edited February 4 by wefalck

[Gregory]

2 hours ago, Chuck Seiler said:

Were you able to determine if the vertical post could be removed/replaced?

Definitely, now that you asked.

Want to kick me now, or later?

I could have got almost 2" of elevation by removing that plastic cap and moving the head up on the post.

There are scads of 12mm chrome rods at Amazon.

Here is a 23" for $18.99.  A 12" would do it for my purposes..

Edit:  Now I see you can choose from 200 to 1000mm.

 

Standby  for super mini drill V2.0

 

Forget you saw that melamine crap, and thanks for the wake-up call.

 

 

 

Edited February 5 by Gregory

[Chuck Seiler]

No worries. thanks.  The posts I have mic out at .508"/12.9mm x 12".  Would it fit?

[Gregory]

There is a bearing with a very tight fit, so I think 12.9 could be a problem.

 

 

 

 

[Chuck Seiler]

I missed your comment about the rods on Amazon.  I'll check them out.

[grsjax]

11 hours ago, wefalck said:

Are you sure it’s the spindle

Specs said the shaft turned in a brass sleeve.  I assume that means the spindle but I could be wrong.  Be interesting to take one apart and see how it is made.

[wefalck]

The main body that houses the spindle as well as the table apear to be pupose-machined parts, the rest is probably off-the-shelf stuff that can be easily sourced on Amazon, ebay, etc.

 

In fact, one could fabricate easily such a drill-press from parts sold for 3D-printers or CNC-mills. Rods and bearings can be found in all sorts of dimensions in the Internet.

 

As to longer columns: the longer the column the more flex there is, which may be not so good for small fragile drill-bits. In fact, the melamin riser-blocks may be not such a bad idea at all.

[Gregory]

9 hours ago, grsjax said:

Specs said the shaft turned in a brass sleeve.

I can't seem to find anything about a brass sleeve in this particular one.

 

Mini Drill Press

 

The one that Ron Burns posted about, and got me started on this does talk about a brass spindle and sleeve..

 

 

Edited February 5 by Gregory

[Chuck Seiler]

10 hours ago, wefalck said:

As to longer columns: the longer the column the more flex there is, which may be not so good for small fragile drill-bits.

I don't think the flex difference between an 8 inch half inch diameter steel rod and a 12 inch rod will be significant, at least for what I am working on.

[wefalck]

It's not the rod that flexes, but possibly the rod in the base-plate ...

[Gregory]

The post is counter-sunk in the base plate with a locking collar.  There is no discernible movement. 

I don't think a 12 inch post vs  8.6 is going to change that, but I will let you know.

 

[kgstakes]

12 mm = .5 inches why not just turn a 1/2” bar stick or metric equivalent and use that?  Wouldn’t that be strong enough?  Or maybe a better idea (I did this on one of my floor drill presses) take the bar or pipe post you have cut it so one part fits in the base just long enough so you could insert a smaller diameter tighten that part together with a bolt and then extend the smaller bar the amount you want raised and then take the rest of the original bar and insert that into the “head end” and tighten that all down with another bolt.

 

 Wouldn’t that work?

[Chuck Seiler]

1 hour ago, kgstakes said:

 Wouldn’t that work?

Sure, if I had the equipment to do that.  But then I probably would not need the press we are discussing.  Easier to spend the $10 at Amazon.

[kgstakes]

Chuck is that post solid or hollow?  If hollow you need a hacksaw hand drill and some bolts.  No special tools needed.  

[kgstakes]

To turn the material down yeah but refer to previous answer hollow post pipe?  Hands tools that’s it.

[Gregory]

Solid.

[Gregory]

14 minutes ago, kgstakes said:

Chuck is that post solid or hollow?  If hollow you need a hacksaw hand drill and some bolts.  No special tools needed.  

How would that solve the problem of the bearings made for a 12mm post?

[kgstakes]

The 12mm bearings,  your cutting the solid bar stock in two pieces and use one for the base and one for the bearings and fill in between with a piece of pipe and bolt tight.  The length of pipe can be any length you want.  The 12mm rod is still attached to the base and will still work in the bearings.  Even if you don’t want to disassemble anything just cut the solid rod with a hack saw,  move them apart the length you want and measure that length at a couple inches (or metric equivalent) drill some holes for bolts and tighten even torque it to make sure everything is back solid.