New Mini-Milling Machine (Harbor Freight)

[DoctorBill]

Dutchman - you wrote about different collets in your post.

Here again, I see how much I have to learn - there are various types of collets !

9BS....Y.....Double Taper....ER16, 32, 40 (?)....Parlec....double angle...100TG......
Coolant Collets......3J

And the types probably go up in price depending on type and maker...

What type collet is best to use on my toy machine ?
Usually I buy the Chinese variety for the cost savings - if not, I couldn't afford to do any of this.

Jeez - I better go buy some Lottery tickets and win BIG TIME MONEY !

DragonRider - I will refrain from buying End Mill Holders....and save my money to buy
better types of Collets !

DoctorBill

[smokeywolf]

DoctorBill,
Concentricity will have considerable bearing on the life of your end mills, and the successful outcome of everything you machine. Runout in a collet could result in a 1/2" endmill cutting a .502 or .503 slot. In addition to that, If your collet has excessive runout it will cause drilled holes to come out over-sized or slightly tapered or funnel shaped. They will cause chatter and poor finishes.
I would look for used Hardinge, Royal, Lyndex or Bridgeport R8 collets on ebay, rather than buy new China made collets.
If it was 5C collets you needed, I have a couple of hundred of those and could set you up with several of those. But regretfully, I don't see any duplicate R8s out in the shop.

smokeywolf

[Dutchman]

What type collet is best to use on my toy machine ?

You'll be fine with R8 collets. I use them, too.

Dutch

[DoctorBill]

I received all the Milling Machine "Kit" from LittleMachineShop.com.

All of it is good stuff.

Here I am using my home made Screw Jack to achieve 90° on the column.
i.e. setting it into 'tram' as one of you called it.

I am using two large "C-Clamps" to use as levers and safety devices
to keep the center post from falling over and to lever it with the screw jack.



I am to 0.004" one side to the other so far....had to stop and finish more
pressing jobs.



DoctorBill

[dragonrider]

What!!! you have a new to you tool and there is a more pressing project????? What a novel concept.

[DoctorBill]

Let's see.....
Every year before the rain, ice and snow, I waterproof my cement driveway
pad with some type of 'WaterSeal' - this time Thompson's.

Had a Driveway Pad poured many years ago and the guy who put it in told
me to do that and it wouldn't spall.

It hasn't ! Stayed nice for over 12 years now !

Then I have to cut down 17 old (50 years) Arborvitaes and put in new ones
as a hedge against the snow that blows over the Palouse here.

Then I got's a trailer full of stuff for the Dump.

Have to fix my car's door handle, find out why the left turn signal won't work,
also why the dash lights won't come on.

Then put in a Nissan Pathfinder AT Temp Gauge and a new Tachometer.

What else....load about 20 30-06's (showing my son how to reload),
then reload about 50 45-70's for myself.....

Lots to do - plus get this Milling Machine going, grade 40 Chemistry labs before Monday.

DoctorBill

[DoctorBill]

I have been trying to square up the Mill - get it into "Tram".

Maybe I am confused - ya think ?

I'm using a Digital Gauge. The swing is 4 inches off the center post.

I set the right side to 0.000. Standing in front of the Mill....

The other side reads 0.004. The Left side.

Now THAT means it is 0.002 off Tram on the left side, yes ?
i.e. it changes by 1/2 the reading on each side.....yes ?



When I go to tighten the large nut that holds the Column steady, the gauge
moves by as much as 0.010 !

I've held the column be hand, tapped it with a Mallet to read 1/2 of the
difference, then tightened the nut and I can pretty much keep it from moving,
but not completely.

My problem boils down to the column moves upon tightening that big nut.
I think I had best loosen it just slightly and tap the column to move so
that it doesn't move when I retighten it.



Any suggestions ? What am I doing wrong, if anything ?

Question #1 -
Is this a situation wherein I repeat this over and over until at some time I somehow get
there after tightening the Big Nut and NEVER loosen it ever again in my lifetime ?!

Question #2 -
Just how good do I have to get this setting ?
Remember, I am not going to be making Gyroscopic Bearings for a Space Probe going
to Jupiter....just Bullet Molds and Ear Wax Removers.....

DoctorBill

[smokeywolf]

DoctorBill,
I'm sure one of the guys that own a HF mini can advise you better than I. This movement when tightening/clamping is somewhat typical of most objects that have to be trammed or indicated in.
Some machinists struggle with this task throughout their career.

Because you're dealing with one nut, your column may drift even more when tightening.
When I tram in a Bridgeport head, I will loosen the bolts (4 of them) completely, then re-tighten them to a little tighter than finger tight. Swing the indicator around and bump the head till close, tighten bolts a little more, swing the indicator again and bump head until real close, tighten bolts more and check tram. If off less than 2 or 3 tenths, I can usually bump it in, tighten the rest of the way and verify. With a Bridgeport you have to do this for both X and Y axis.
The closer you can get the head to absolute perpendicularity to table, the better your milled finishes will be. If the your endmill isn't at absolute 90 degrees to your table, when you try to mill a surface flat the leading side of your endmill will do all your cutting while the trailing edge fails to touch the work at all. When you reverse the table feed the leading edge will do some of the cutting, but the trailing edge will do more cutting yet. Which sometimes leaves a poor finish and unpredictable measurements.
If you don't have access to a tenth indicator, I would be trying for 0.0005 or less difference from side to side.
On the Bridgeport I shoot for less than a tenth. Most times there is enough slop in spindle bearings and table ways/gibs that 1 ten thousandths of an inch is an impractical goal. But I'm more than a little O.C.D.

Some machinists are very reluctant to tilt the head of the mill.

smokeywolf

[DoctorBill]

It appears that I am doing this correctly...

http://www.machinistblog.com/how-i-tram-my-mini-mill/

That Big Nut (I don't mean myself !) is the problem.

So I suppose I will loosen it just barely enough to allow the column to
move with tapping by a rubber mallet, then tighten and hope for the best.

DoctorBill

[HollowPoint]

It appears that I am doing this correctly...

http://www.machinistblog.com/how-i-tram-my-mini-mill/

That Big Nut (I don't mean myself !) is the problem.

So I suppose I will loosen it just barely enough to allow the column to
move with tapping by a rubber mallet, then tighten and hope for the best.

DoctorBill

With my mini-mill I never had any illusions of perfection. After all it's a cheaper chinese hobby machine.

That being said; the closest thing to perfection in "Tramming" for me was using a bubble level in the X and Y axis and a carpenters square in the Z axis. For my applications that was Good Enough. It would be nice to get everything perfectly aligned though.

I too had the problem with tightening the big nut on the back and it throwing off my vertical alignment. I ended up polishing the backside of the big nut and the facing side of the of that cone-shaped washer.

With a dab of grease on both of these polished surfaces, when I tightened the big nut it tended to lessen the effect of moving the column in the direction I was tightening.

Your milage may vary.

HollowPoint

[oldred]

Ah the joys of set-up!


I think you will find that set-up of both work pieces and machinery will often take more time than the actual milling process itself and sometimes frustration before success just has to be dealt with. Most times it's easy enough to get a work piece where you want it but getting it there and keeping it there while fastening it down may be time consuming, just part of the process however and a person's patience here will surely result in closer tolerances as the pay off. Like most anything else however this gets much easier with practice and you will learn little tricks and short cuts that will make the job a lot less bothersome and time consuming.



BTW, I notice no one has warned you about what you are getting into! It's too late for you now anyway because you have already been exposed to the highly addictive hobby of home machining for which there simply is no cure. This ailment knows no other relief except to continue to feed the insatiable addiction with a never ending requirement for more tooling and gadgets, but it sure is fun trying!

[DoctorBill]

I got there from here....

Just barely loosened 'the big nut' and tried again.

Had to whack the column harder - doubt if I can hurt anything with a
rubber mallet.

Got there fairly quickly and when I tightened the Big Nut, I pushed down
on the top of the column as I tightened the nut.

Didn't move like before.

Long story short - somewhere between 0.0005 and 0.001 inch.
Close enough for Government Work - Especially NOW.

An Obamamobile


Whew !

Now to put the vice on.
I took all the stuff in the kit over to my friend Gary the Machinist to show him
what it looks like. He says it all should work well for me and is good equipment.

He said I should lose the Milling Vice Rotating Table portion of it and mount the
vice directly to the table - his Honking Large Milling Machine is set up w/o a
rotating vice - just bolted directly to the table.

So I did that...now to align the jaws with the X axis.



DoctorBill

[yarro]

A great upgrade for the mini mill from Little Machine Shop is the metal gears and belt drive conversion. Taking too big a bite and breaking teeth off the stock plastic gears means disassembly and waiting for the parts. Mine is MT3, but when I got mine they weren't offering R8 else I would have gotten that taper instead.

-yarro

[DoctorBill]

http://littlemachineshop.com/product...2560&category=

Lord ! another $145......

DoctorBill

[oldred]

http://littlemachineshop.com/product...2560&category=

Lord ! another $145......

DoctorBill

Don't forget the couple of hundred you will need for the rotary table you will soon want and then there is........well it just doesn't end.

[smokeywolf]

Once you indicate your vice, you can start making chips.
Remember, speeds and feeds. Medium to fast feed on aluminum. Medium feed on stainless. Lighter feed on high carbon steels.
As long as the depth of your thread is at least equal to the diameter of your tap; when tapping aluminum, a 75% thread is sufficient, when tapping stainless or titanium, a 55 - 60% thread is quite sufficient. Blind holes, use a helical flute tap. Express or thread-forming taps can be real good in aluminum and plastics.
Crisco or kerosene can serve as a pretty good cutting & tapping lube/fluid on aluminum. A commercial cutting fluid with a high volatility does better on higher carbon steels and stainless.

smokeywolf

[Chicken Thief]

I use one of these a lot

http://www.axminster.co.uk/gemred-di...ox-prod564900/

And live by this rule:
Feed against the cutting edge!!!
There is so much play in the spindles that it will chatter if it is allowed to "selffeed"/mill with the cutting edge.

[DoctorBill]

SmokeyWolf - what does it mean when you speak of % thread ?
as in "...when tapping aluminum, a 75% thread is sufficient."
One either taps or on doesn't tap.....(?)

Chicken Thief - what do you mean by ,"Feed against the cutting edge!!!
.............it will chatter if it is allowed to "selffeed"/mill with the cutting edge"
Do you mean - raise the tool when going back ?

Remember - I am a novice who doesn't know much jargon yet.

DoctorBill

[Chicken Thief]

Think of the cutter as a wheel spinning.
When you feed into the running direction it will drag the material into itself, trying to lead forward.
That is not desireable on such a little machine.
If you feed against the spinning direction the play will all be eleminated.

So feeding from left to right, mill on the side away from you.
Feeding from right to left, mill on the side facing you.
If you mill on the short axis, it will most often chatter so try to avoid that (due again to slop/play in the spindles)
I have had mine for the past 4 yrs so please ask away!

[Chicken Thief]

This one is a No-no on this little thing



This one is the way to go