I need advice on making non- standard diameter holes

I will glue them together with super glue and mill / drill / bore the holes all in one go. Heat to seperate the plates afterwards. Wash away the residues with Acetone. Quick and easy.
 
mickri said:
If I read your tolerance correctly the holes can be up to .005 undersize but not oversize. For example the .830 hole can range in size from .825 to .830. Drills tend to drill a slightly oversize hole. Using the metric drills should give you a hole within spec. You can also buy end mills in those sizes.
Click to expand...
I just edited my post to include tolerance. + or - .005" , so not real critical.
 
Comes down to the number you need to do and how much you want to spend on tooling vs. outsourcing. There is also the positional accuracy that you need. Stacking multiple pieces by welding or gluing can be an issue with regard to positional accuracy on the plate and the cutter walking as you go through each plate. I would be more inclined to set up a jig/stop system and doing one series of holes, then setting up for the next hole. This assumes you are not doing a large number of plates, at which point I would look at some form of automated cutting system. Drills in thinner metal will tend to distort the steel when drilling and can punch through the bottom unless you use a sacrificial backing plate to drill into. With a jig or stop system using annular cutters, each hole should take less than a minute using a mill.

The set of metric annular cutters should bring you with in spec. as 0.1mm is 0.0039" and must of metric ones will end up within the lower bound of the -0.005" spec. Hougen makes a metric series that will handle up to 1/4" thick steel. It is important that you follow the speed recommendations fro the annular cutters, which are slower, apply constant feed pressure and use lubrication. The metal peels off very cleanly in strands, there is also very little punch through edge or metal deformity. They give very clean consistent holes. Reamer could be used for close tolerance holes, I often use them if I need a specific close +tolerance over spec.

You also will need the mandrel to go with these but they are very handy to have. I use their Holecutter series for cutting holes in steel enclosures.
9mm https://www.travers.com/product/hougen-11209-annular-cutter-or-tool-26-035-781
$11.05
11mm https://www.travers.com/product/hougen-11211-annular-cutter-or-tool-26-035-783
$13.92
15mm https://www.travers.com/product/hougen-11215-annular-cutter-or-tool-26-035-787
$19.91
21mm https://www.travers.com/product/hougen-11221-annular-cutter-or-tool-26-035-793
$28.38
 
Another option is to just make a handful of single-point cutters. If you take some round tool steel, turn it down to the required diameter, grind it in 'half' near the bottom and cut relief angles, then harden/temper it (skippable if this is HSS), you'll have a custom single-point boring tool of the right size. At that point, I'd drill slightly undersized, then use the tool to finish the hole. A bit of work, but perhaps worth it if you have a number of these to make.
 
mksj said:
Comes down to the number you need to do and how much you want to spend on tooling vs. outsourcing. There is also the positional accuracy that you need. Stacking multiple pieces by welding or gluing can be an issue with regard to positional accuracy on the plate and the cutter walking as you go through each plate. I would be more inclined to set up a jig/stop system and doing one series of holes, then setting up for the next hole. This assumes you are not doing a large number of plates, at which point I would look at some form of automated cutting system. Drills in thinner metal will tend to distort the steel when drilling and can punch through the bottom unless you use a sacrificial backing plate to drill into. With a jig or stop system using annular cutters, each hole should take less than a minute using a mill.

The set of metric annular cutters should bring you with in spec. as 0.1mm is 0.0039" and must of metric ones will end up within the lower bound of the -0.005" spec. Hougen makes a metric series that will handle up to 1/4" thick steel. It is important that you follow the speed recommendations fro the annular cutters, which are slower, apply constant feed pressure and use lubrication. The metal peels off very cleanly in strands, there is also very little punch through edge or metal deformity. They give very clean consistent holes. Reamer could be used for close tolerance holes, I often use them if I need a specific close +tolerance over spec.

You also will need the mandrel to go with these but they are very handy to have. I use their Holecutter series for cutting holes in steel enclosures.
9mm https://www.travers.com/product/hougen-11209-annular-cutter-or-tool-26-035-781
$11.05
11mm https://www.travers.com/product/hougen-11211-annular-cutter-or-tool-26-035-783
$13.92
15mm https://www.travers.com/product/hougen-11215-annular-cutter-or-tool-26-035-787
$19.91
21mm https://www.travers.com/product/hougen-11221-annular-cutter-or-tool-26-035-793
$28.38
Click to expand...
You read my mind!
This run will only be 4 pieces, so I think this is the way to go.
Location of the holes may be more important than the diameters, so I don't plan on stacking the plates. Those annular cutters should get me close enough. I've never used one before so I didn't know what to expect to see where the tool exits the piece. It's gotta be better than using drill bits.
It'll be the 1st real job I get to do on my new mill! I just got a PM 940 V-PDF mill with the DRO. (from Precision Mathews)
That DRO is nice. I can plot the locations for all of the holes beforehand and use a jig set up for repeatability.
I don't have a coolant system yet. Hope doing that part manually will suffice for now.
thx
 
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