made some chips...

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liveaboard
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made some chips...

Post by liveaboard »

My first job on the mill; cutting a gear rack to fit the slot in the top slide.
I wanted to set it up for horizontal and it took a while.
The table had to be flipped around the other way, it sits higher and closer in that position.
horizontal milling.jpg
The oil pump didn't work; someone had taken it out and wired it backwards when in went back in.
I had to shorten the arbor I got from UK, to fit the bargain box of cutters I got from the UK, and I had to make a bushing for it too.
Then drill out the zerk for the bushing and put in another.
I was quite pleased with my first try, it came out quite close. After this I cut most of the length, it still needs to have another 2" cut.
first job pretty close.jpg
So, any tips on cleaning up all these needle sharp oil soaked chips?
first chips.jpg
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Bill Shields
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Re: made some chips...

Post by Bill Shields »

Flip table?

It unbolts from the ways -> or you rotate everything...ways and all?

Shop vac...for the chips

Once had a virtually new shaper..ok it was 30 years old when I acquired it..but maybe had 10 hours of running on it

Had literally no cutting oomph...motor was running backwards and probably had been since day 1.
Too many things going on to bother listing them.
pete
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Re: made some chips...

Post by pete »

Well I'm more than suitably impressed Mark. Rack cutting for your first part is a huge step. Yep those needles milling creates, a literal pita and other places if they go down your shirt. :-) Bill does what I do, that Shop Vac is much preferred over even compressed air. I bought a new dirt cheap 2" wide paint brush for each of my machines, there in constant use and in case you don't know it yet, re-cutting chips in the path of the cutting tool seriously degrades your cutting edge life. So moving the chips with a paint brush away from the cutting tools path is also done. And the paint brush keeps you from getting your hand in where it shouldn't be. You'll figure that out the first time the cutting tool grabs the paint brush and chews it to nothing.On any machine that doesn't have high pressure flood coolant that Shop Vac is the next best choice.
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Harold_V
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Re: made some chips...

Post by Harold_V »

One thing to consider when operating side milling cutters is the number of teeth doing the work. Your feed rate should be great enough that each tooth makes a chip (at least five thou per tooth), which helps eliminate those needles you spoke of. That said, when you operate such a cutter with the proper spindle speed, so the chips aren't coming off discolored, the feed rate is rather frightening. Flood coolant is your friend.

You likely already know to not climb mill with this type of setup. Doing so can be a real disaster.

Way to go! Looks like you landed on your feet with this purchase.

H
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liveaboard
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Re: made some chips...

Post by liveaboard »

Thanks;

To clarify; I didn't cut the teeth on the rack, I bought it ready made (it wasn't expensive), I'm just cutting it down to fit.
Yes, the table unbolts from... whatever the part is that holds it up. An assembly with the ways and cross screw.
The table weighs 150lbs, it looks like it was rarely if ever mounted this way before.
There are various tables made for this machine, I only have the basic one. It can be moved right to left on slots, or turned around as shown.

I'm not sure what qualifies as flood coolant; the manual specifies 30 weight oil, and there is a pretty good stream of it. Those needles are saturated with it, I'm hoping most of the oil will drain out overnight because the waste is all stuck together with oil.

I'm using a very low spindle speed, maybe too slow, 45rpm. the cutter is 120mm, slightly under 5". The cut is very smooth.
Feed is slow too, I sped it up a couple of notches; 6.5 meters a minute I think, 21'.

On the long cut, the work is 0.05mm undersized at the ends of the cut, and 0.05mm oversize in the center, just about what I measured as the table wear last week. I think this will fit ok, but I can't check without taking the machine apart, because I'm using the machine to make a part for itself.

I need to cut it down in the other dimension as well, with the teeth down against the table, the 17x17mm rack will be 10.0 x 9.1mm.
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Harold_V
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Re: made some chips...

Post by Harold_V »

Assuming the material is mild steel, you could run faster, up to 100 rpm safely. Feed? Without knowing the number of teeth, there's no way that can be determined. Chip load per tooth is what you need to determine.
The finer the chips, the more they'll retain the oil. Given enough time, they should drain fairly dry, though. Oil is a great lubricator, not quite so good in heat transfer, but it's a good choice for the guy who uses coolant only occasionally. It will eliminate the problems of water based coolants.

Lookin' good!

H
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tornitore45
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Re: made some chips...

Post by tornitore45 »

[Had literally no cutting oomph...motor was running backwards and probably had been since day 1.
But I bet it had a very fast return.
Mauro Gaetano
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John Evans
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Re: made some chips...

Post by John Evans »

Well Mark that looks aprox 63 SFM . assuming rack is mild steel 100-120 SFM . So if you have around 80-90 RPM available that would put you in the 100SFM area. Horz. work with large diameter cutters gets the SFM numbers up fast ! Not like when you are using a 1/2" end mill. Get the RPM up a bit then adjust the feed rate to get courser chips. Nothing like a horz. with a big/wide wheel cutter to move metal. Looking good.
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pete
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Re: made some chips...

Post by pete »

Maybe this will help you not having to learn a few things like I did Mark. Milling has some important differences compared to machining on a lathe. So in case you don't already know? For the most part gravity helps with chip control on a lathe unless you get a birds nest. With a mill it's easy to have a condition where re-cutting of the previously cut chips starts happening. That's bad both for your surface finish, but even worse it really decreases your cutting edge life. And blade type milling cutters are a whole lot more expensive to buy or have resharpened than end mills. It's a common rookie mistake to think it's not that important and I did the same. One way or another it's vital that it's prevented from happening. I bought cheap 2" wide paint brushes for each of my machines and there always in use cleaning the cutting path in front of or even behind the cutting tool in slots, or brushing chips off the way surfaces and tooling. I also use compressed air or that shop vac depending on what might work better. And that brush keeps your hand from getting in where it should never be if the machine is rotating. The first time the cutting tool on a mill grabs that brush and mangles it to useless you'll understand what I mean. And those paint brushes are used for everything even with a machine not running, sweeping out chips from the vise jaws between parts, off the tops of the parallels etc. There one of my most used tools. But with flood coolant or cutting oil it's still better to wipe down the vise jaws, parallels etc with a shop rag.

Picking feeds, speeds and depths of cut for each material type and diameter is a lot easier on a lathe. With a mill there's a lot more variables that have to be considered. .002" - .005" or more chip load per tooth are only guidelines. It's not hard to find solid carbide end mills with diameters well under .100" in diameter. I have a tiny set of carbide boring bars for my boring head I've so far not had enough guts to try, the smallest one is capable of starting with a minimum bore of around .053" in diameter. Good luck keeping any really small end mills or tools from instantly breaking with a .002" tooth load. Even the parts size or cross section may not take those chip loads. I've also seen recommendations in a few of my older books that mention dropping the cutting tool sfpm down to 50%-60% of maximum for tools like thin HSS slitting and slotting saws. If you don't yet have one, try and find a used version of Machinery's Handbook. Those older ones from maybe 1940 - 1970 or so have a lot more information about different HSS milling cutters when horizontal milling with HSS was much more common than the newer ones do. The nice part is you have a choice with your mill between vertical and horizontal milling. With larger parts and large amounts of material needing to be removed that horizontal milling will remove it multiple times faster just due to the better tool support so much deeper cuts and more aggressive feed rates can be used.

Other than light finishing climb cuts it's very much not recommended to do climb cutting on any mill without ball screws. But there's a trick you can do to save some work if you plan out your tool paths. I'll use vertical milling with a fly cutter or face mill as an example. If the tool diameter is larger than the part face you can make a single pass across it. That works fine except it leaves a large burr on the part at the tool tip exit side where the cutting tool tips are coming off the part. The metal is being bent and folded over instead of being cleanly cut off. If you use the tool rotation direction and go around the parts perimeter in a square and always cut towards the center of the part you get almost zero burrs. The same obviously works with end mills when cleaning up the face of a part. I see lots on Youtube using end mills of a lot smaller diameter than the part size to face off a flat surface or cut it to depth using multiple passes. Unless there's a part design reason so your forced to do so, it's a very expensive method to do it that way because of what those end mills cost and there finite tool life. I've pointed it out before, but fly cutters are limited to light depths of cut only. They work well and I try and use one when I can. There a cheap tool to use but very slow if there's much material to be removed. Even a cheaper off shore face mill that uses replaceable carbide tips will pay for itself multiple times over due to how much it saves using up end mills to do the same job. And it will do it a whole lot faster. If you do end up buying one just be sure to buy one that uses the most common and economical tips. The triangular shaped TNMG inserts probably, but I don't know what you have the easiest and cheapest access to. If you run across a used face mill? Be 100% sure of exactly what inserts it uses before buying. There's lots of older used tooling around and some of it used proprietary and brand specific inserts that are no longer available. And I bet that problem is even more common in Europe than over here.
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liveaboard
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Re: made some chips...

Post by liveaboard »

Pete, thanks for your advice; I'll try to keep all that in mind.
Looking for machinery's handbook, what I can access is a bit costly.
And I could be wrong, but isn't everything in there in Imperial measurements?
Because that really limits its use for me.

I bought a bunch of different cutters from Ebay UK in the 6 months before Brexit, I got some bargains; I'll take some pictures later. I'm still waiting for collet chucks I ordered from Czech republic, delivery people are confused.

A close up of the chips made earlier show that they are not needles, but rolled up flakes;
chips closeup.jpg
I removed the top slide with the spindle head still on it, and fitted the cut down gear rack into the slot. I had to grind it down slightly where it was 0.05mm oversize, I didn't think such a tiny error would have so much effect but it wouldn't fit until it was 10.00 or less everywhere.
top slide with rack installed.jpg
I cut down the driving gear earlier. I made these spokes and balls for the handles, quite laborious considering.
top slide drive gear and parts.jpg
And after triumphantly assembling, it turns out that the balls don't clear the lower slide.
AARRGG!
I'll just weld the spokes to the hub and bend them outward. If it ever needs disassembly, they can be cut off.
topslide handle error.jpg
For now I have to stop milling and do other work for a few weeks.
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topslide handle new.jpg
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NP317
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Re: made some chips...

Post by NP317 »

Looks like another job well done.
I admire your tenacity and skills.
RussN
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Bill Shields
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Re: made some chips...

Post by Bill Shields »

looking good...

still scratching my head wondering why anyone would take the rack out in the first place...???

difficult 2 believe it would have been worn out -> maybe broken teeth from someone hammering on it...
Too many things going on to bother listing them.
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