[dbruins]

To continue to PCNC 770 build as discussed here ...

We were debating metric vs imperial. Posts 6, 7, & 8 are illuminating.
In summary, the main advantage of metric is the ease of base-10 math.
While the advantages of imperial include availability and price.

Questions:

1. Just to be clear. I can design in CAD in metric and the CAM software will automatically "adjust" for imperial tooling?
2. I'll be cutting aluminum mostly. Are there desirable brands, materials, and coatings and ones to avoid?

Thus far tool holding and Tormach tools these items are on my list:

Tool Holding
	32284	CNC Operator's Set (or metric 32291)	$795.00
	30233	TTS-MT3 Collet & Drawbolt	$29.76
Tools
	31807	Modular Tension / Comp Tapping Head Kit	$345.73
	33031	TTS SuperFly Cutter Kit	$148.50
	32447	TTS Diamond Drag Engraver Kit	$68.79
	32452	90* Replacement Diamond Dragger Bit	$23.99
	32453	120* Replacement Diamond Dragger Bit	$23.99
			$1,435.76

As the decision to go metric or imperial has not been finalized, the long list of possible cutting tools include ...

MSC Industrial Supply
End Mills
Metric
$	Size	Shank	Reach	Flutes	Corner Rad	Material	Coating	Brand	Order #
33.49	2	6	15	2	0.20	Carbide		Accupro	93161586
32.51	4	6	15	2	0.25	Carbide		Accupro	93161644
32.51	6	6	16	2	1.00	Carbide		Accupro	93161719
50.04	10	10	25	2	1.00	Carbide		Accupro	96161768
148.55
Ball End Mills
Metric
$	Size	Shank	Reach	Flutes	Corner Rad	Material	Coating	Brand	Order #
21.43	1.5	3	6	4		Carbide	TiCN	Accupro	1217819
23.14	4	4	14	4		Carbide	TiCN	Accupro	1217868
28.69	6	6	19	4		Carbide	TiCN	Accupro	1217892
53.74	10	10	25	4		Carbide	TiCN	Accupro	1217934
127.00
Chamfer Mills
Metric
$	Size	Shank	Reach	Flutes	Corner Rad	Material	Coating	Brand	Order #
59.88	8	8		4		Carbide	SIRA	Seco	81019226
Drill Bits
Metric
$	Size		Angle			Material	Coating	Brand	Order #
73.60	1-10 by 0.5mm		118			HSS	Oxide	Hertel	07574932
175.60	1-10 by 0.5mm		118			HSS	TiN	Dormer	80980840
Tap & Die
Metric
$	Size					Material	Coating	Brand	Order #
104.25	M3-M12					HSS	Bright	Hertel	59337535
175.20	M2.5-M12					HSS	TiN	Hertel	88244215
McMaster Carr
End Mills
Metric
$	Size	Shank	Reach	Flutes	Corner Rad	Material	Coating	Brand	Order #
17.69	2	3/16	6.4	2		HSS	TiN		8694A12
16.86	4	3/8	11.1	2		HSS	TiN		8694A16
17.18	6	3/8	12.7	2		HSS	TiN		8694A21
20.51	10	3/8	20.6	2		HSS	TiN		8694A27
72.24
13.85	2	3	6.3	2, 3, or 4		Carbide	TiN		8866A231
17.76	4	4	14.0	2, 3, or 4		Carbide	TiN		8866A271
21.67	6	6	19	2, 3, or 4		Carbide	TiN		8866A321
37.45	10	10	22	2, 3, or 4		Carbide	TiN		8866A361
90.73
Drill Bits
Metric
$	Size		Angle			Material	Coating	Brand	Order #
60.67	1-10 by 0.5mm		135			HSS	Black & Gold		30155A55
110.38	1-13 by 0.5mm		135			HSS	Black & Gold		30155A57
73.08	1-10 by 0.5mm		118			HSS	Bright		30555A64
105.08	1-13 by 0.5mm		118			HSS	Bright		30555A66
Tap & Die
Metric
$	Size					Material	Coating	Brand	Order #
189.23	M3-M12					HSS			2646A14
Kodiak Cutting Tools
End Mills
Metric
$	Size	Shank	Reach	Flutes	Corner Rad	Material	Coating	Brand	Order #
10.37	2	3	6.3	4		Carbide		Kodiak	133769
12.78	4	4	14	4		Carbide		Kodiak	133813
16.33	6	6	19	4		Carbide		Kodiak	133846
34.09	10	10	22	4		Carbide		Kodiak	133890
73.57
End Mills
Imperial
Kit
	1/8	1/8		2 or 4		Carbide	ALTiN	Kodiak	2 flute
	3/16	3/16		2 or 4		Carbide	ALTiN	Kodiak	6I-RY3N-FNED
	¼	¼		2 or 4		Carbide	ALTiN	Kodiak
	5/16	5/16		2 or 4		Carbide	ALTiN	Kodiak	4 flute
	3/8	3/8		2 or 4		Carbide	ALTiN	Kodiak	F6-78KG-DBQ3
	½	½		2 or 4		Carbide	ALTiN	Kodiak
99.99
MSC Industrial Supply
End Mills
Imperial
$	Size	Shank	Reach	Flutes	Corner Rad	Material	Coating	Brand	Order #
21.77	5/64	1/8	6.4	4	0.015	Carbide	TiCN	Accupro	58736374
26.62	3/16	3/16	15.9	4	0.02	Carbide	TiCN	Accupro	86642931
34.51	¼	¼	19.1	4	0.03	Carbide	TiCN	Accupro	86769775
44.22	3/8	3/8	22.2	4	0.06	Carbide	TiCN	Accupro	87829222
127.12
McMaster Carr
End Mills
Imperial
$	Size	Shank	Reach	Flutes	Corner Rad	Material	Coating	Brand	Order #
14.84	1/8	1/8	12.7	4	0.015	Carbide			30705A11
19.87	3/16	3/16	15.9	4	0.02	Carbide			30705A17
24.20	¼	¼	19.1	4	0.03	Carbide			30705A26
38.65	3/8	3/8	25.4	4	0.045	Carbide			30705A46
97.56
Kit
	1/8	3/8		2		HSS	TiCN		88505A34
	3/16	3/8		2		HSS	TiCN
	¼	3/8		2		HSS	TiCN
	5/16	3/8		2		HSS	TiCN
	3/8	3/8		2		HSS	TiCN
	½	½		2		HSS	TiCN
104.54
Kit
	1/8	3/8		4		HSS	TiCN		88505A43
	3/16	3/8		4		HSS	TiCN
	¼	3/8		4		HSS	TiCN
	5/16	3/8		4		HSS	TiCN
	3/8	3/8		4		HSS	TiCN
	½	½		4		HSS	TiCN
128.33
Chamfer Mills
Imperial
$	Size	Shank	Reach	Flutes	Corner Rad	Material	Coating	Brand	Order #
37.72	3/8	3/8		4		Carbide			3073A67

[kstrauss]

In most (if not all) CAM software one gives the diameter of the cutter. Consider that every imperial sized cutter is not "dead on" and you may want to tell the CAM to assume a 0.249 diameter cutter rather than 0.25000. When working with metric parts some CAM systems may require that you define a 1/4-endmill as 6.35mm but that is normally done once when setting up the tool database.

It isn't clear from your price list but I would never order only one of any size of endmill. There is nothing worse than trying to complete project on Saturday afternoon and break the only proper sized cutter in inventory. My usual approach is to never order less than 3 cutters of a particular size. Some suppliers offer discounts when purchasing 5 or 10 of a single size.

You should carefully consider the Tool Assistant 32284 kit since you will probably never use some of the items in it. Unless you plan to use Weldon style cutters the setscrew holders don't properly grip endmills. I haven't done the sums but there may be sufficient discount that the setscrew holders are "free". I also don't like the Tormach keyed drill chucks that are in the kit since a key is required to change the bit. I greatly prefer a keyless Albrecht chuck. Or even better, use an ER collet to hold drill bits. You will probably also want a set of metric ER20 collets since the collets in the kit don't cover the full capability of ER20 holders. Either get a Tormach 32306 collet set or pay half as much and get two sets from CTC (CTC Tools Home Page ). You will probably soon decide that you need more holders too!

Rather than the digital height gage in the kit, the money might be better spent on a Tormach 31875 tool setter. I haven't bought one yet and there are other vendors that are considerably cheaper. Just something for your consideration since the height gage + granite plate is about $250 and is less convenient to use.

[tmarks11]

Unless you plan to use Weldon style cutters the setscrew holders don't properly grip endmills.

Matter of personal preference. I prefer to use the endmill holders instead of collets... but than all of the endmills I have do have "weldon flats" on them to allow the setscrew to hold. If you go wander around a professional machine shop, you will find a lot more end mill holders than ER style collets.

Just a note on MSC-Direct. Their normal prices are insanely high. Their sale prices are what most other places charge as normal. Every few weeks they have a sale, frequently like "UP TO 45% off metalworking". They key words are "UP TO", as you won't get that kind of discount on everything, and stuff already on sale doesn't get discounted. They are the choice of professional machine shops because you can get your order the next day. Even if you order on a Sunday.

Bottom line: NEVER order from MSC Direct unless you are buying something on sale. They do have a good selection of cutting tools, however.

If you are buying HSS and carbide endmills, I prefer to go to Enco (which, strangely enough, is owned by MSC Direct). They had a 20% off sale that ended a couple days ago, but don't worry, such sales happen every 3-4 weeks. Fill up your Enco shopping cart between sale, and when the sale coupon comes out, press BUY.

Another good place to buy is CarbideDepot. Or MariTool.

Rather than the digital height gage in the kit, the money might be better spent on a Tormach 31875 tool setter. I haven't bought one yet and there are other vendors that are considerably cheaper. Just something for your consideration since the height gage + granite plate is about $250 and is less convenient to use.

+++1

There are many ways to skin this cat, but I find granite block + height gage much less convenient than just zeroing each endmill while chucked up in the mill (which will automatically record the endmill height offset in the tool table).

[SCzEngrgGroup]

Unless you plan to use Weldon style cutters the setscrew holders don't properly grip endmills.

I use set-screw holders all the time on tools with no Weldon flats, and I've never once had one move one bit, even on the most aggressive cuts.

Regards,
Ray L.

[Hirudin]

To answer your main question (and to reiterate a little): yes, any CAM program that's worth a **** will let you use both imperial and metric tools. The reason for that is: "they" really can't stop you. Converting between inches and mm is exact. A 1/4" cutter IS a 6.35mm cutter*. Those two numbers may be written differently, but what they represent is exactly the same. I think it's worth noting that you will not enter "1/4" into the CAM program's tool table, you'll enter "0.25". I only mention that to make light of the fact that both numbers (0.25 and 6.35) have two significant digits following the decimal place. Also, the CAM program isn't going to care if the numbers following the decimal point are all zeros or are all different. Sure, some conversions won't work out so perfectly, but most (all?) CAM programs will let you stretch your tool measurements out to at least four digits past the decimal when working with imperial units or three digits with metric. Anything beyond that would be basically meaningless when talking about milling... I mean, it's hard enough to accurately *measure* differences that small, it's not worth it to worry about them in the tool table.

* you could also call it a "~0.0139 cubit" cutter if that's what you're into.

The diameters of the bits are the diameters of the bits. The CAM program isn't going to care what you use to measure them as long as you convert your units into units it can understand.

Conversely, the marked size of the cutters aren't exact, as kstrauss mentioned. Take a "3/16in" end mill for example. The decimal equivalent of 3/16" is 0.1875". The metric equivalent is 4.7625mm. That "3/16" bit might be undersized by a "tenth" (0.0001") or two. The actual diameter might be 0.1874". Well, oddly enough, the rough metric equivalent of that is 4.76mm. There, you've saved yourself two significant digits... not that it matters. Similarly, take a "5mm" end mill and measure it with a micrometer. It's probably going to be a tenth or two undersized as well. Suddenly your "5mm" end mill is actually 4.995mm.

Basically, all I'm trying to say is that the numbers etched into the side of the end mills you buy are just a number. As long as the CAM program is given an equivalent number that it can understand: you'll be fine. You might be wondering "well, why go with imperial then?". The answer to that is simple enough: imperial tool holders (collets, in particular) are readily available. A 1/4" collet will hold a 6mm end mill, but not perfectly. It'll hold a 1/4" end mill a little better. You could probably shove a 5mm end mill into a 3/16" collet, but it probably wouldn't hold it properly. A 13/64" collet would work OK for a 5mm end mill, but 13/64 is an oddball size that you're less likely to have on hand and it's less likely that they'll be available locally.

[tmarks11]

If you are buying HSS and carbide endmills, I prefer to go to Enco (which, strangely enough, is owned by MSC Direct). They had a 20% off sale that ended a couple days ago, but don't worry, such sales happen every 3-4 weeks. Fill up your Enco shopping cart between sale, and when the sale coupon comes out, press BUY.

And there it is:

20% OFF with promo code: 20WED through 11pm ET on 01/14/15.
15% OFF with promo code: 15THUR through 11pm ET on 01/15/15.
10% OFF with promo code:10FRI through 11pm ET on 01/16/15