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[Project 5] Low Profile Table Clamps

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Ron Laden26/05/2020 06:33:47
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Posted by JasonB on 25/05/2020 19:01:15:
Posted by Ron Laden on 25/05/2020 11:04:39:

I can't get my head around the recommended speeds for fly cutting they have never worked for me so I must have been doing something wrong.

What does work for me is higher rpm, for Lee, s cuts of 0.3mm and 0.75mm I would go with something in the region 600 rpm for the 0.3 in steel at say 50mm diameter and 350 rpm for the 0.75mm.

That is with a HSS cutter usual angles and a rounded nose.

I know you will tell me it's wrong but all I can go by is it works, gives a good finish, the mill sounds happy with no issues.

Looks like we will both be getting a slapped wrist, I'd be running faster too.

Here we are with a 63mm flycutter so probably swinging 80mm dia at the tip (HSS), first cut at 600rpm 40mm/min approx feed and second cut a 300rpm with a feed reduced accordingly, not a bad finish for a slow one handed feed, could have got it better if I was not holding the camera. material 40mm wide EN3b. No sign of vibration.

Edited By JasonB on 25/05/2020 19:07:33

Yes Jason we could be sent to the naughty corner but interesting you found similar results. In my case I wondered if it is my mill being a small 500 watt machine, 175 - 200 rpm with say a 0.5mm cut puts me into stall territory. If I double the speed to 350 rpm I don't have a problem, machine is happy, finish is good which I think comes from the machine getting more into its power band.

Lee, why don't you try 600rpm for the 0.3mm cut and 300rpm for the 0.75mm as Jason shows in his video, if the tool is something like good you should get similar results, worth a try.

Ron

JasonB26/05/2020 07:11:52
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Posted by Ron Laden on 26/05/2020 06:33:47:

Lee, why don't you try 600rpm for the 0.3mm cut and 300rpm for the 0.75mm as Jason shows in his video, if the tool is something like good you should get similar results, worth a try.

Ron

They were both 0.3mm DOC, Don't think I'd go match above 0.5 on the SX2.7 for that width of steel. But as I say run then fast and shallow and you can do two cuts in the same time as one deep one at slow speed.

Having spent the first 11-12yrs of mill ownership using a variable speed machine with no Tacho I go but what sounds right and gives a good finish and seldom calculate a speed. I only fitted a Tacho to the X3 so I could transfer the speeds over to the SX2.7 as that is so much quieter you don't think it is turning! - No gerbox which brings us back to where the noise is as the interupted cut just loads and unloads the gear train, the higher momentum also helps reduce this.

Ron Laden26/05/2020 08:20:32
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1916 forum posts
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Sorry my mistake I should have realised, I thought you were copying Lee,s cuts.

Lee Jones 626/05/2020 08:53:16
140 forum posts
88 photos

I did some playing around last night.

Reground the tool (excessive clearances).

img_20200525_181819.jpg

img_20200525_181833.jpg

Results (remember, you have to click on the video to see more than the preview):

0.3mm DOC - 180RPM - 36mm/min

0.3mm DOC - 280RPM - 36mm/min

0.3mm DOC - 280RPM - 20mm/min

0.3mm DOC - 600RPM - 40mm/min

Best surface finish, by far, was the 600RPM cut, but it was very noisy.

It sounded like the machine was taking a beating.

oldvelo26/05/2020 08:55:45
204 forum posts
50 photos

Hi

Fly cutter with the tool stuck out flailing a large radius on a small width workpiece NBG on a gear drive train.

Keep the diameter of the cutting circle just a fraction wider than the job when flycutting to minimize the torque load on a chattering gear chain. Belt drive is infinitely smoother running on intermittent cutting

Three toolbits mounted on 52 mm cutting head will cut faster with one bit starting the cut and the previous one exits.

dscf0426.jpg

dscf0428.jpg

Setting up is a breeze take out the clamp bolt and fix the setup jig in its place to get all the tips equal by installing the toolbits to sit on the jig and do up the clamp screws.

Sharpen dull HSS tips with an oilstone for longer life and almost mirror finish.

Lee Jones 626/05/2020 09:08:13
140 forum posts
88 photos

I do not currently have any plans to make new fly cutters.

In fact, I'm only using (playing really) this one until the new carbide inserts for my face mill arrive.

Not sure I can get any less stick-out than I already have. Maybe 5mm, but I've seen SO a lot further than mine.

Incidentally I have noticed a small flat spot on the base of my cutter. I think my grind needs to be improved.

Ron Laden26/05/2020 09:24:54
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Well done Lee, good that you have got a better finish. I am not used to the sound of your machine of course but the 600 rpm cut didn't sound that bad to me, sounded better than the slow cuts I thought.

Ron

Lee Jones 626/05/2020 09:46:23
140 forum posts
88 photos

Recording on the mobile phone doesn't seem to pick-up the banging sound, which is a shame.

Lee Jones 626/05/2020 09:51:22
140 forum posts
88 photos

Jason,

When cutting a shoulder, did you say it was better to come in from the side?

I have Harold's 'Milling A Complete Course' and he seems to suggest chewing away 2mm coming top down.

JasonB26/05/2020 13:05:04
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I would indeed come in from the side so that you get to use more of the flutes otherwise you are just wearing the end of the cutter. That's for a HSS or carbide 2, 3 or 4 flute cutter, the facemills seem to work better the other way round on my machines.

Edited By JasonB on 26/05/2020 13:06:26

Lee Jones 626/05/2020 15:26:15
140 forum posts
88 photos

Mmmm... Pretty!

img_20200526_135003.jpg

img_20200526_141451.jpg

Martin Connelly26/05/2020 20:20:05
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1364 forum posts
159 photos

I think fly cutting with HSS bits at RPM that result in a higher than recommended surface metres per minute are benefiting from air cooling over most of the revolution. Just to show that slower RPM with correct feed works here is an example. This is a piece of scrap hot rolled steel about 25mm across. RPM=166, DOC=0.1mm, feed=18mm/min.

p1150165.jpg

Martin C

Edited By Martin Connelly on 26/05/2020 20:26:56

Martin Connelly27/05/2020 14:17:48
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1364 forum posts
159 photos

Lee, the low profile clamps mentioned earlier are here. They are priced for industry not home use but will give ideas on how to make your own.

WDS parts

Martin C

Lee Jones 627/05/2020 14:36:06
140 forum posts
88 photos

Thanks Martin. For the video and the link.

Lee Jones 627/05/2020 14:40:18
140 forum posts
88 photos

Sneaky nap-time session:

img_20200526_204218.jpg

img_20200527_140316.jpg

img_20200527_140316.jpg

Lee Jones 627/05/2020 18:40:45
140 forum posts
88 photos

Other side milled:

img_20200527_182311.jpg

Lee Jones 627/05/2020 18:41:11
140 forum posts
88 photos

Not sure how I'm going to do the vertical cuts yet.

John Baron27/05/2020 20:29:14
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290 forum posts
122 photos
Posted by Lee Jones 6 on 27/05/2020 18:41:11:

Not sure how I'm going to do the vertical cuts yet.

Bandsaw !

Lee Jones 627/05/2020 20:30:31
140 forum posts
88 photos

Never mind laugh​​​​​​

img_20200527_194246.jpg

img_20200527_200001.jpg

Lee Jones 627/05/2020 22:28:00
140 forum posts
88 photos

Finished for the day:

img_20200527_221056.jpg

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