# A Compact Metric Drill Index



## RJSakowski (Jan 24, 2022)

A year or so, I bought a set of metric drills, 1.5mm to 13mm by .5mm. It didn't come with a drill index so for the last year, they have just remained in a bundle. To make them easier to access, I decided to make a stand for them. (Details below)




I had delayed the project because of a lack of suitable material for the base. I needed a block about 4" x 4" x1.5" and wanted to use a plastic of some kind. (I prefer not to use wood because it attracts moisture causing swelling and possible rusting.) A check on likely sources of a suitable plastic proved unfruitful as the material cost was excessive. I decided to try to cast my own, using recycled plastic. My choice of materials was polypropylene as it has fairly decent mechanical properties and a fairly low melt temperature.

I selected a can from tomato sauce from the recycle bin for a mold as its diameter was almost 4". I heated the can to burn off the epoxy coating on the inside of the can. I calculated that I would need about 10 oz. of material for the raw slug. For a heat source, I used my hot air gun set at 390ºC and broke up the material and melted it bit by bit until the material was completely added. When the slug cooled, I peeled the can away.

Using the lathe, I turned the slug to 3.5" diameter and faced it to a thickness of 1.25". The next step was to drill the pattern for the drill bits. My design criteria for the pattern was that the drills be arranged in two concentric circles with the largest bit at the center. For stability and ease of access, the larger drills would be on the inner circle. Drills would be arranged in a descending order and the spacing between adjacent drills would be constant. This presented a fairly complex mathematical challenge which could be addressed in a spreadsheet but was fairly easily done in SolidWorks.

SolidWorks was able to position the required holes and could spit out the coordinate of each hole. However, transcribing the coordinate of 25 holes and keeping track of them while drilling is a highly susceptible to user error. A simpler approach for me was to export the model to SprutCAM and use it to drill pilot holes. With the click of a few buttons, the hole locations were set and the machine op of spot drilling the hole locations was run and posted to G code.

 G code loaded into the Tormach, I set my x & y zero in the center of my blank and touched off the #2 center drill on the top of the blank. No need for precision here. Two minutes later all 24 holes were spotted. The work was moved to the mill drill for drilling the holes. Drill sizes were chosen to be slightly larger than the prospective tenant but not large enough to accommodate the next larger drill. This gave a .5 mm or .020" window for selecting an appropriate drill. The DRO was zeroed on the top of the blank and holes were drilled to a depth of 1" for each drill. I started with the smallest hole and worked my way up. To keep track of where I was, I inserted a pin in the hole after it was drilled.

The enclosed Excel spread sheet contains a table of drill location coordinates and a table of suitable holes sizes for each drill.  The drawing will help to visualize the locations of each hole.  A text file provides the G code for CNC drilling.  Some modification may be required to adapt to your specific CNC mill.


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## Martin W (Jan 24, 2022)

Very well done!
Martin


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## woodchucker (Jan 24, 2022)

nice, but what did you use for the polypropylene raw material?


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## RJSakowski (Jan 24, 2022)

woodchucker said:


> nice, but what did you use for the polypropylene raw material?


The clear covers from Chinese takeout containers.  For those who don't know, polypropylene is #5 in the recycle triangle.  It is also commonly used for caps on disposable plastic containers.


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## matthewsx (Jan 24, 2022)

woodchucker said:


> nice, but what did you use for the polypropylene raw material?


Milk jugs?

see your answer now. Great use of home recycled material.

John


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## RJSakowski (Jan 24, 2022)

Milk jugs (at least ours) are high density polyethylene, #2 in the recycle triangle.


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## woodchucker (Jan 24, 2022)

I save them to make mixing pallets for epoxy. I just cut them with a knife...  Good to know. Better than sticking them in the landfill.


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## mmcmdl (Jan 25, 2022)

Our filters are made from Polypro . Every time we purge the dies we end up with 50 to 60 lbs of it in 2' x 1.5' x6" deep stainless tubs . Our lines have 5 dies each , so we have tons of the stuff every night . Right before I went out on sick leave , I made up a split mold for a plastic chain sawing wedge . They worked pretty good for a cheap free thing . What are some other things that can be molded ?  









						Just a simple mold . G job .
					

Since I now have 87 cans of mold release , I need a mold ! :grin: Not having a need for one I had to think up something that I use often . Only thing I came up with is felling wedges for the tree work lately . I whipped out a fast cheapy split cavity mold in a hour but didn't have to purge any...




					www.hobby-machinist.com


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## Ken from ontario (Jan 25, 2022)

Very interesting project, are you completely done with it now? I mean is there something else you're planning to add to it, like labels for the smaller drill sizes?  or turning it to a carousel? just thinking out loud.


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## Navy Chief (Jan 25, 2022)

Great work, I would never have even thought of melting down and molding my own plastic slug for a project. Adding this to the mental file for future reference.


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## RJSakowski (Jan 25, 2022)

Ken from ontario said:


> Very interesting project, are you completely done with it now? I mean is there something else you're planning to add to it, like labels for the smaller drill sizes?  or turning it to a carousel? just thinking out loud.


No need for a carousel as the stand is quite compact.  In fact, it is easily and reliably moved by just grasping the cluster of larger drills.  Placing the larger drills in the center rather than all the drills on a single circle makes it a very stable stand as well as compact.  

As to labeling, I wondered what I could do in that regard.  Certainly, the CNC was/is capable of engraving the sizes.  The inner circle is fairly tight and it would be hard to read any size.  As for now, I will probably just verify the size with a caliper.  If that becomes too annoying, O will take appropriate action.


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## ConValSam (Jan 25, 2022)

Very nice solution. Couple of questions about working with the material:

Is the plastic melting stinky? 

Is it something better done outside or with an exhaust fan nearby?

Did you have to super clean the lids to avoid contamination?

TIA


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## RJSakowski (Jan 25, 2022)

mmcmdl said:


> Our filters are made from Polypro . Every time we purge the dies we end up with 50 to 60 lbs of it in 2' x 1.5' x6" deep stainless tubs . Our lines have 5 dies each , so we have tons of the stuff every night . Right before I went out on sick leave , I made up a split mold for a plastic chain sawing wedge . They worked pretty good for a cheap free thing . What are some other things that can be molded ?
> 
> 
> 
> ...


That's a great project.  In all the years that I have been cutting wood, I never bothered with felling wedges but there were times when I wish that I had them. There are a lot of things that can be molded with a simple open mold.  Aside from PP, HDPE, and possibly PS are material candidates.  I have been saving PS scrap from discarded equipment for years now, awaiting some project.  Certainly a better use that going to landfill.

In a former business that I was part of, we made molded polypropylene components for a product we sold.  We only used virgin material so any scrap was just disposed of.  Another company that I worked for made slabs of epoxy composite material for calibrating therapeutic x-ray machines and had some rather stringent requirements on thickness, flatness, and uniformity, etc.  This resulted in a fairly high percentage of scrap that was just binned.  It would be a nice candidate for this project except for the fact that it contains powdered limestone which plays havoc with HSS cutting tools.  Had I a set of carbide drills, that would have been my choice of materials.  But then, I would have to make another index for them.  

Another possible material candidate is ubiquitous Bondo.  A fairly simple process to make a slug of it for a project and cheaper than epoxy.  Polester resin used in fiberglassing would be another possibility.  Additives like wood flour of grinding dust could modify the mechanical properties.  Both are considerably less expensive than epoxy resin.


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## mmcmdl (Jan 25, 2022)

RJ can answer per what he made .   

As far as melting Poly , there is no odor . We blow it thru dies anywhere from 450-600 degrees . We do have exhaust fans , more to take the heat out of the rooms . They are all kept below 60 degrees per our processes . We have very large silos full of different size pellets from Exxon and Amoco as well as many others that come in 1000 lb totes . I may be sensitized to the smell if RJ has a different opinion .


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## RJSakowski (Jan 25, 2022)

ConValSam said:


> Very nice solution. Couple of questions about working with the material:
> 
> Is the plastic melting stinky?
> 
> ...


Yes there were fumes coming from the melt process.  Originally, I was melting at 600ºC which resulted in fumes.  I dialed it back to 390ºC which reduced the fumes.  When I finished, and went upstairs, I noticed a haze.  Opening the windows for a few minutes cleared it out.  If I had a melt pot or an oven rather than a hot air gun, I probably could have lowered the temperature further.  Doing it again, I would probably move hte operation outdoors.

The lids were quite clean to start with. I rejected one that had some foreign material on it.  Other than that, I did no other cleaning.  I wasn't making rocket parts, just looking for a hunk of plastic.


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## mmcmdl (Jan 25, 2022)

As a cautionary note , this stuff flashes . We've had 4 major fires over the last 4 years at the plant . These were due to operator negligence . Our last was a very very expensive F up . The dies purged from Friday afternoon until Sunday morning , the op left for the weekend and forgot to shut the line down . The poly purged , and purged , and purged until it was 4 ft high and hit the band heaters . Burned up the entire room , the extruders , pumps , cabinets and of course flooded the entire half of the plant . The fire department was the only ones that could shut off the sprinkler system per county regs .


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## RJSakowski (Jan 25, 2022)

Polypropylene is very much like candle wax in that respect.  Once ignited, it burns very hot.  I definitely would avoid any open flames when dealing with it.  Aside from that though. I routinely weld it with a soldering iron and have never had an incident.


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## mmcmdl (Jan 25, 2022)

RJSakowski said:


> Polypropylene is very much like candle wax in that respect. Once ignited, it burns very hot. I definitely would avoid any open flames when dealing with it. Aside from that though. I routinely weld it with a soldering iron and have never had an incident.


Did you end up with a solid chunk without porosity in your slug RJ ? I'm curious . The wedges ended up being porous due the extruders just dumping into the mold and not under any pressure . It would be cool to make up a few cheap arse molds and be able to dump the heated plastic right into them , or put the mold onto a hotplate and melt it . Hm ..................you have me thinking .


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## woodchucker (Jan 25, 2022)

mmcmdl said:


> Did you end up with a solid chunk without porosity in your slug RJ ? I'm curious . The wedges ended up being porous due the extruders just dumping into the mold and not under any pressure . It would be cool to make up a few cheap arse molds and be able to dump the heated plastic right into them , or put the mold onto a hotplate and melt it . Hm ..................you have me thinking .


I have a hotplate. That way I can take it outside to the garage and melt it without stinking up the house.

Now, you have me curious. I was thinking of saving plastic bottle caps as well, since they might be a good candidate for the meltdown....  Just need a food grinder, to chop the plastics up into shreds...   a food processor... gotta see what the wife has that she isn't using


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## mmcmdl (Jan 25, 2022)

Uh oh ..........................see what RJ started ?   

I have to visit work today anyway , I'll pick up a bag of this stuff and do a little experiment tonight .


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## RJSakowski (Jan 25, 2022)

mmcmdl said:


> Did you end up with a solid chunk without porosity in your slug RJ ? I'm curious . The wedges ended up being porous due the extruders just dumping into the mold and not under any pressure . It would be cool to make up a few cheap arse molds and be able to dump the heated plastic right into them , or put the mold onto a hotplate and melt it . Hm ..................you have me thinking .


I had air inclusions in my slug but I attributed that to my method of heating.  Even though I made an "oven" out of fire  brick, the bottom was cooling below the melt point.  I expect that the temperature has to be a fair degree hotter than the melt point to get good flow  or to allow air inclusions to work their way to the surface.  As i recall, the temperature for injection molding was fairly close to the melt point so minimize shrinkage and warping.  We also used a fairly high pressure to pack the mold.


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## RJSakowski (Jan 25, 2022)

I have an old Fry Daddy deep fat fryer that will melt PP.  I tried it today and the temperature will reach 450ºF.  The PP that I used solidifies at 300ºF. At 450ºF, it is definitely molten although it appears to be too viscous to easily pour.


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## woodchucker (Jan 25, 2022)

RJSakowski said:


> I have an old Fry Daddy deep fat fryer that will melt PP.  I tried it today and the temperature will reach 450ºF.  The PP that I used solidifies at 300ºF. At 450ºF, it is definitely molten although it appears to be too viscous to easily pour.


Put some mold release on the fryer, and when it solidifies put a wood screw or a few in and pull out the chunk.
Or put some Aluminum foil inside, line the inside.


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## RJSakowski (Jan 25, 2022)

woodchucker said:


> Put some mold release on the fryer, and when it solidifies put a wood screw or a few in and pull out the chunk.
> Or put some Aluminum foil inside, line the inside.


No need.  The PP shrinks as it cools and lifts right off the Teflon coating.


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