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Milling for beginners

Please use this thread to ask questions of make suggestions about the series in MEW

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Martin Connelly12/01/2019 11:45:12
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You can get tap driving sockets from Snap On that can be held with a collet such as R8 but allow the tap to self align and move up and down a small amount. A bit like a cheap and compact tapping head.

**LINK**

Martin C

Ron Laden12/01/2019 12:52:19
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Thanks Martin but there is no problem tapping on the SX2P with the tap mounted correctly in a collet. Why some people use a loose collet with the drawbar partly unscrewed I have no idea as there is no need.

From what I have found I think the key is to have the head well balanced. I changed the lever and spring over to a gas strut which has left the head quite free to operate and its lost the heavy feel it had on the lever/spring. It takes very little effort to keep the head in front of the tap, in fact I can do it with one finger and there is no binding or sign of the tap trying to pull or push the head.

Ron Laden13/01/2019 08:01:32
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Posted by JasonB on 12/01/2019 08:38:49:

Ron as soon as the SX2.7 goes into tapping mode it uses a different set up on the chip, Ketan has confirmed to my that the torque of the spindle is much increased using his scientific "Gauntlet" test and although the tap stops and reverses very quickly there is some ramp down and ramp up so as not to strain things.

For yours I would watch to see if the motor starts to get hot if doing more than one or two and also pause in the neutral position before going straight to reverse.

Also I'm not sure if your stop start using the speed control is the ideal way to be using the mill, I would need to check with Ketan whether you should have the speed set than use the on/off at the side. So tapping would be set a speed & direction - green on button - tap hole - red off button - change direction - green on reverse tap out - red off.

Jason, having checked the mill this morning I think once again you are probably quite correct in suggesting using the on/off switch for the change in direction. If I use the speed control the mill starts/stops instantly whereas with the on/off switch there is a 2-3 second pause before it starts up.

Ron

JasonB13/01/2019 08:15:58
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I think that is your best bet if you are going to do more powered tapping

Posted by Ron Laden on 12/01/2019 09:02:09:

Thanks Jason, Ketan did tell me that the SX2P does have built in torque increase at low revs and I know that to be true as the mill has surprised me once or twice with decent power at low speed.

The extra torque that I mentioned when going into tapping mode is over and above normal slow speed running. Ketan tested the mill in normal slow running and then at the same speed in tapping mode and there was a lot more torque available.

Neil Wyatt13/01/2019 08:25:26
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I expect the controller assumes tapping will only be for a short time, so it can allow a higher current for tapping without risk of overheat.

Neil

Ron Laden13/01/2019 08:26:13
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Posted by JasonB on 13/01/2019 08:15:58:

I think that is your best bet if you are going to do more powered tapping

Posted by Ron Laden on 12/01/2019 09:02:09:

Thanks Jason, Ketan did tell me that the SX2P does have built in torque increase at low revs and I know that to be true as the mill has surprised me once or twice with decent power at low speed.

The extra torque that I mentioned when going into tapping mode is over and above normal slow speed running. Ketan tested the mill in normal slow running and then at the same speed in tapping mode and there was a lot more torque available.

I dont have that of course but it was good to know that the mill does have at least some increase at low speed.

JasonB26/06/2019 11:21:41
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I had an enquiry on the video I did of the SX2.7 threading aluminium using the tapping mode as to whether it would also tap steel. So I did a quick video yesterday of it tapping M6 x 1 into steel and then there is always one who asks if it will do bigger/better etc smile p

So I have joined these two together.

Material 1/4" EN3 steel, drop of CT90 tapping fluid.

M6 x 1 spiral flute tap into 5.0mm hole @ 200rpm

M10 x 1.5 taper hand tap into 8.5mm hole @ 150rpm

Seemed quite happy to do them both though a spiral point or spiral flute would have been preferred choice for the M10 thread if I had one. Anyone in the market for these type of taps or the traditional taper, second and bottom taps may want to take a look at ARC Euro Trades site as they have just added a new range of threading tools to their range here

Edited By JasonB on 26/06/2019 16:26:45

Ron Laden26/06/2019 13:31:41
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Hope this is ok on here Jason.

Slitting saw blades, what makes them coarse, fine or extra fine..?

I have 2 x 80mm blades, a 1.0mm and a 1.5mm and both of them have 32 teeth and are listed as "fine". I have a job coming up that needs a 3.0mm blade and I have found one with a different supplier and it is also listed as fine but it is 75 teeth..? Obviously there are two ways of looking at it, if the 32T is fine then the 75T must be extra fine and if the 75T is fine then the 32T is coarse. A bit confusing but I guess at the end of the day its a case of choose what you think best suits the job.

Ron

Andrew Johnston26/06/2019 14:00:02
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There's no definitive definition. In this picture I would regard all the slittling saws as coarse apart from the one bottom right:

slitting saws.jpg

The size of gullet is the important factor. A fine tooth slitting saw is ok for slotting a screw head. But if you want to take a 1/2" or more depth of cut with a slitting saw you need a large gullet for the swarf, and hence fewer teeth for a given diameter.

Andrew

Edited By Andrew Johnston on 26/06/2019 14:00:36

Ron Laden26/06/2019 14:03:01
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Thanks Andrew, that makes perfect sense.

Ron

JasonB26/06/2019 14:29:41
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Hope this is also OK one here but I would say our usual supplier has them wrongly listed as fine.devil

I would say your 32T ones at that diameter are generally regarded as coarse and 75T on a similar diameter as fine. You don't see many medium ones about.

Probably better to look at it as tpi rather than number of teeth 32T on a 25mm dlabe would be considerably finer than the same number on an 80mm blade so much like using a hacksaw you would select a finer tpi if sawing thin sheet or thin wall tube than you would if hacking your way through a 50mm solid bar so for cuts in thin material of where the depth is shallow a fine blade is best like when slotting a screw head.

photo 91.jpg

But a coarse one is better if slicing through thicker section material especially something like aluminium where you can use a highter chip (tooth) load that means more swarf to fill the gullet.

photo 92.jpg

Seem to remember seeing those photos in an article I read not that long ago that said the same sort of thing

J

Ron Laden27/06/2019 08:48:23
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Posted by JasonB on 26/06/2019 11:21:41:

I had an enquiry on the video I did of the SX2.7 threading aluminium using the tapping mode as to whether it would also tap steel. So I did a quick video yesterday of it tapping M6 x 1 into steel and then there is always one who asks if it will do bigger/better etc smile p

So I have joined these two together.

Material 1/4" EN3 steel, drop of CT90 tapping fluid.

M6 x 1 spiral flute tap into 5.0mm hole @ 200rpm

M10 x 1.5 taper hand tap into 8.5mm hole @ 150rpm

Seemed quite happy to do them both though a spiral point or spiral flute would have been preferred choice for the M10 thread if I had one. Anyone in the market for these type of taps or the traditional taper, second and bottom taps may want to take a look at ARC Euro Trades site as they have just added a new range of threading tools to their range here

Edited By JasonB on 26/06/2019 16:26:45

Your test prompted me to see what the SX2 is capable of and I think M6 in alu which it handles well is probably its limit though I havnt tried M6 in steel as yet. I did try M10 in alu but it didnt like that at all and it just about coped with M8 in alu but not ideal. The SX2 is a smaller machine than the SX2.7 of course with less power so I couldnt expect too much plus your machine has a tapping facilty which I dont. I,m guessing I should be able to thread steel M5 and smaller, will have to give it a try.

JasonB27/06/2019 08:54:34
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The tapping mode also alters the torque settings so that helps.

I have some taps from ARC's new range coming so will see how they perform both under power and by hand.

Emgee27/06/2019 09:05:22
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For those who are not aware of the different uses of the taps Ketan as usual provides information on which tap to use for blind or through tapping.

Emgee

Ron Laden27/06/2019 09:10:33
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Posted by JasonB on 27/06/2019 08:54:34:

The tapping mode also alters the torque settings so that helps.

I have some taps from ARC's new range coming so will see how they perform both under power and by hand.

Yes I was looking at the new range from your previous link, the prices seem very good too. For machine tapping spiral flute or spiral point..? I will be looking at M6 and smaller.

Ron

Our posts crossed Jason, I see the last one re Ketan and info, thanks Emgee

Edited By Ron Laden on 27/06/2019 09:12:16

Edited By Ron Laden on 27/06/2019 09:17:20

Edited By Ron Laden on 27/06/2019 09:18:42

JasonB27/06/2019 09:32:24
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Posted by Ron Laden on 27/06/2019 09:10:33:
For machine tapping spiral flute or spiral point..? I will be looking at M6 and smaller.

 

That rather depends on the machine and tooling. For a machine equiped with a tapping head or a CNC mill then the spiral flute for blind holes will not be a problem. On your SX2P where the machine has to be stopped and reversed manually there is a risk of driving the spiral flute tap into the bottom of the hole. So in your case I would say don't machine tap blind holes unless you can drill them with enough depth to allow a safety margin to stop the machine in, same applies to ones with a tapping function like the SX2.7 and SX3

Through holes are not such a problem though that too can depend on the shank diameter of the tap , small ones may not have a reduced shank so could be driven into the hole and the shank foul. Spiral point will be the better for through holes though you could also use spiral flute.

If all else fails you can still use both these taps by hand though I would suggest tapping while still set up in the mill or at the very least a tapping guide/stand as they have less of a lead in taper than the traditional taper tap so won't line themselves up as easily.

If i only had the choice of one from spiral point of flute then I personally would go with spiral flute for general hobby use.

 

Edited By JasonB on 27/06/2019 09:36:01

Ron Laden27/06/2019 11:12:14
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Thanks for the information Jason, very helpful.

Ron

JasonB27/06/2019 17:52:51
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Well the postie finally came and dropped off a box with some goodies inside.

Yesterday I had opened that M10 hole out to 10.3mm ( actually 13/32" ) and tried my taper tap in it which has no make on it and don't recall where or when it arrived in the workshop as it is not a size I use that much. I tried two chucks both keyed and keyless but it just stuck and span in the chuck, changing to an ER32 wich just tripped the machine instead when it got too much.

So armed with the set of spiral flute taps from ARC Euro Trade's new range and suitable tapping drills I popped a 10.2mm hole into another offcut of 1/4" steel, reverted back to the keyed chuck that came with the SX2.7 to hold the M12 tap, set machine running at 150rpm and had a go. Slowed a bit at first but then just powered through the hole with a clean looking thread produced.

 
I would say that is about on the limit for what this machine could do and would not want to do a lot of them in quick succession, 10.2mm does give a high percentage thread depth and that could always be upped a bit to make life easier on the mill but may try at a few other speeds which could prevent that initial slowing. Will test them further and hopefully have something to go in the next but one MEW.
 
J
 
PS Nice boxes too.

Edited By JasonB on 27/06/2019 17:56:48

Ron Laden28/06/2019 08:19:11
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The same as when I tried a M8 taper hand tap in alu, it hesitated but then made its way through so M6 is the limit on the SX2P I think. I am not planning on doing a lot of machine tapping but if a job comes up with a number of threaded holes its good to know I can use the mill, though it will be the smaller sizes.

I will get myself some of the spiral flute taps from ARC,s new range, pricing looks very good as do the sets of hand taps.

Ron

Ron Laden29/06/2019 11:23:34
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Its a pity ARC dont have a 80mm/22mm bore/3mm thick slitting saw in their range. For the 8 axle box spring mounts I need to cut a 3mm slot 12mm deep across the end of 1/2" steel bar and it looks as if I will have to go with a 72 tooth cutter. I cant find a coarser blade in that size well not at a sensible price, I havnt looked at the expensive ones.

So I am hoping it will work ok, I think it should unless anyone tells me otherwise.

Ron

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