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End Mills for Roughing Mild Steel

With the Bridgeport rapidly coming together I need to get to grips with the capability of the larger machine. The first job I have for it is to cut 5/8" square slots in 2" square free cutting mild steel in lengths of 18" or so. I have a few to do.

Is there a cutter that I can use that will do this in one pass on an old Bridgeport. If that is too ambitious what endmills will give me the least passes? While I wouldn't attempt this will a normal 5/8" HSS endmill I have no experience with the recent range of high production roughing mills so any advice on their capability, price and where to get them would be much appreciated. The size of the slot is not critical +/- .005" will be fine but I would like a reasonable finish on all cut faces if possible.

Any advice would be much appreciated

Best regards

Keith

Reply to
jontom_1uk
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Obviously I've upset you all?

Any idea where I can get a 16mm "roughing" (ripper?) end mill to cut mild steel for less than the =A357 that J&L list?

Keith

Reply to
jontom_1uk

Cromwell part No SWT-163-4276A £28.55 inc VAT?

Mark Rand RTFM

Reply to
Mark Rand

Huh! Depth is 4 times the diameter at a full cut. I think you have to ask for a cutter that can do it. for HSS, depth is 1/2 the diameter, with a roughening cutter, depth = diameter is no problem.

You'll never get that with a roughening cutter in one pass or even 10. You need to make a finishing cut. You will discover, that the roughening cutter is flexing sideways (or your Briggy).

Nick

Reply to
Nick Mueller

When you say '5/8" square' slots are these 5/8" deep & 5/8" wide, by

18" long, like a long keyway? If so, why not use a 5/8" slot drill? My Elliott would do that quite OK in two passes, maybe one if I pushed it, a Bridgeport might need three. Always feed in the same direction, lift the cutter out to return to the origin or you'll get a tapered or oversize slot. 18" will get tedious after the first couple if you haven't got a powered table feed.

HTH

Tim

Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service

Reply to
Tim Leech

Look in the J&L Advantage flyer, I'm sure I some cheap ones in there. I actually bought 3 12mm ones last month. I also have a set of what I would call "Nasties", cheap foreign ones as shown on ebay which have the flatted shank style I don't use. eBay Item number: 320059870032. I think the set goes for £25. Bob

Reply to
Emimec

snipped-for-privacy@4ax.com...

Thanks for the advice guys; as usual I didn't describe it too well. As Tim guessed it is a 5/8 x 5/8 slot in effect. Thanks for the pointers from Mark and Bob, for some reason I always forget Cromwell surprising as my (not so local) branch is fairly good. I have trouble finding the "deals" using the web sites of J&L and particularly RS so I should get on their paper list I suppose. A search usually takes me to the "list" price which doesn't always link to the offers.

Nick's advice on finish means that I will need to make more than one pass anyway so I will go with a HSS slot drill as Tim suggests and try

3 cuts to start - have to look after these "lightweight" Bridgeport machines. I will pick up some roughing endmills to increase my experience but perhaps in a more economical size. As Bob says I'm not a fan of those flatted shank style cutters as I can't see how they can possibly be concentric when loaded from one side as most are. I have been pleasantly surprised a couple of times now by "cheapo" cutter sets and my latest "risk" was on a set of dovetail cutters at Warwick, I expected nothing for the price but they cut surprisingly well.

Thanks to all for the advice

Keith

Reply to
jontom_1uk

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