# Level The Table?



## gubni (Jul 18, 2016)

Saturday I bought a 1979 JET-16. I am pretty excited about learning how to use it. The primary reason I got it is that I sell disc brake kits and sometimes I need to make a brake pad thinner. That should be pretty easy with a mill.

My problem is as I cut about 2" wide 8" long the left rear corner is about .05 deeper than the right front. The reason I bought a mill is that I wanted it exact from one side to the other.

I'm not sure if anyone can help unless you have the same machine, but I thought I would ask.


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## Chipper5783 (Jul 18, 2016)

Have you trammed the head?  I don't know if there are any adjustments (looks like a mill drill)?  Even if it does not, you still need to do a sweep so you know if it is out.  Out of whack by 0.05" front to back is a lot (sort of a twist to it - you have something wrong).  You may have to unbolt the column and re-align everything.  In the mean time, you can shim your work.

Also, you won't get it "exact".  You work to a tolerance (fancy word for "good enough").  You should have no trouble getting to ±0.0005" (still not exact, but probably good enough).


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## gubni (Jul 18, 2016)

Have you trammed the head? -- Since I am not familiar with that term, then no, lol

I don't know if there are any adjustments (looks like a mill drill)? -- Yes it is

Even if it does not, you still need to do a sweep so you know if it is out. -- I did sweep the floor before before I set it up, but I have a feeling you are referring to something else.

Out of whack by 0.05" front to back is a lot (sort of a twist to it - you have something wrong). -- Well mostly right to left over 8" with a little front to back.

You may have to unbolt the column and re-align everything. -- Sounds like one heck of a job.

Also, you won't get it "exact". You work to a tolerance (fancy word for "good enough"). You should have no trouble getting to ±0.0005" (still not exact, but probably good enough). -- That would be very good.

Attached is a pic.


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## Paul in OKC (Jul 18, 2016)

Are you holding the parts in the vise? May be 'rising' on you as you cut. If you are running left to right, and the part is flat in the vise, you should not have that much run out. A little concave-ness maybe. Are you thinning the pad, or the metal? May need to clamp to the table for a more rigid set up.


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## chips&more (Jul 18, 2016)

A pic of your set-up please. Or you will get all kinds of random help/ideas.


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## gubni (Jul 18, 2016)

First of all I attempted to level the C channel to use as parallels. I got it fairly close by trail and error. The pad in this pic is just one I have played with, so ignore the patterns in it, but it is typical size I would work with.


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## gubni (Jul 18, 2016)

Paul in OKC said:


> Are you holding the parts in the vise? May be 'rising' on you as you cut. If you are running left to right, and the part is flat in the vise, you should not have that much run out. A little concave-ness maybe. Are you thinning the pad, or the metal? May need to clamp to the table for a more rigid set up.



I was told this is a Wilton vice. I have checked after cutting and I don't think that's the case. I am going right to left. I am thinning the pad which is a relatively soft surface.


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## 4GSR (Jul 18, 2016)

gubni said:


> I was told this is a Wilton vice. I have checked after cutting and I don't think that's the case. I am going right to left. I am thinning the pad which is a relatively soft surface.



That's a old Bridgeport vise.


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## brino (Jul 18, 2016)

Hi gubni,

Welcome to the group!

First some terms:
By "tram the head" we mean get the spindle set accurately to 90 degrees to the table both left-right(x-axis), and front-back (the y-axis).
Some mills allow adjustment in various directions to allow special cutting set-ups. "tilt" and "nod" are commonly used terms.
On yours it doesn't look like you have these advanced adjustments. Don't worry, you can still do many of the same advanced operations, you just need to be more creative in your work holding, maybe using sine-plates, etc. But that advanced stuff can wait.
However, you still need to "tram the head".

By "sweep" we mean to place a sensitive measuring device in the spindle (and with the mill turned off!), place the indicator against the table and move the table to look at how the indicator reading changes. You want to place the indicator against a smooth flat surface, so you are not just measuring the table dings and holes (yikes!) left by the previous users.

The measuring device can be a "dial indicator" like this:


from here: http://littlemachineshop.com/products/product_view.php?ProductID=4285&category=

or a "dial test indicator" like this:


from here: http://littlemachineshop.com/products/product_view.php?ProductID=3709&category=

Note the difference between those two.
On the dial indicator the bottom plunger moves up/down to take a reading.
With the dial test indicator the lever-arm on the bottom moves back and forth, but you can change the angle that it covers.

Ideally, you want zero difference while moving the table, realistically, you need to determine what's required by the job and what's possible with the equipment.
-for x-axis you can put the indicator on the top of the table between the t-slots if the table is not too banged up
-for the y-axis you can still run the indicator on top the table, you just need to lift it over the t-slot gaps.

First get the table trammed in, and then introduce the vise.

For your machine I believe tramming requires you to install/adjust shims under where the vertical column bolts to the base.
I know it may sound daunting, but with some thought and effort I am sure you can get it.
I know there is a thread here about tramming a machine like yours.....though it may take me a while to find it.
When(if?) I do , I will post a link here.

Once the head is trammed to the table, then get the vise trammed in too. Bolt the vise down loosely to the table, run the indicators along the fixed jaw of the vise, and adjust it with little taps from your hand or a mallet. When it's right, tighten it down.

50 thou is significant....it should not be this far out. There is a problem that needs to be corrected.
However, I would not shoot for +/-0.0005 either; (that's 5 tenths of a thou.!) that would just drive you crazy.
For many automotive applications I have found 5 thou (0.005 ") to be plenty accurate.

Other thoughts:
Could there be some chips under one end of your work?
Could there be some chips under one end of your vise?

Good luck!
Please post back with any questions or progress.

-brino


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## brino (Jul 18, 2016)

....oh and one more thing....

Do they still use asbestos in brake pads?
I have read conflicting answers to that question.

If they do be very careful!
I do not know what all the precautions should be, but I'd think a shop-vac may just make the particles air born.....making them more dangerous.

Play safe!
-brino


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## dlane (Jul 18, 2016)

Looks like a t slot cutter in there , might try a fly cutter or a face mill. Use parallels, tram vice


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## Paul in OKC (Jul 18, 2016)

Looks like a piece of channel used for parallels, if so, is it flat and true?


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## chips&more (Jul 18, 2016)

A slot cutter does not cut very well/at all on its end/sides. For this reason, the cutter can ramp up as it travels the cut (if I understand your set-up). I would use a regular end mill. And I would strap that brake pad down onto the table and not use the vise.


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## francist (Jul 18, 2016)

Just thinking out loud here, but the brake pads have bolt holes in them. Why not just bolt them right to a fixture plate and be done with it? Skim the fixture plate first and then everything after that should follow parallel, wouldn't it?

-frank


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## T Bredehoft (Jul 18, 2016)

Before you cut again, (after you've determined that the head is square with the table) (the vise was removed for this operation wasn't it?) remove the lower portion of the vise, (the part that is now attached to the table) from the vice and store it in a secure place. It's for rotating the table to a specific angle and you are not doing that in this operation. Before you put the vice back on the table gently run a whetstone over the bottom of the vice to determine that there are not high spots on the bottom surface.  Do the same with the table. You don't want to remove any but high spots, so don't be aggressive, just wipe it gently. Wipe both table and vice bottom with a paper towel, put the vise down and slide it around to verify there are no chunks of anything under it. Secure it to the table.  NOW with an indicator in the quill, run the vice back and forth to verify that the bottom of the opening of the vise is parallel with the movement of the table. Now try another cut. Yes, use a fly cutter or a face mill.


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## gubni (Jul 18, 2016)

Thanks so much for the ideas. I will work on these as I have time and report back.

For anyone else that might find this thread here is a link to the owner's manual.

http://asavage.dyndns.org/Jet-16/Manual_1/JET-16.pdf


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## talvare (Jul 18, 2016)

Check out this youtube video on tramming a milling machine. 






You can find many videos on-line to help you out. The one I've attached is by a gentleman named Tubalcain. He has over a hundred videos that are quite useful for amateur machinists.

Ted


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## John Hasler (Jul 18, 2016)

chips&more said:


> I would use a regular end mill. And I would strap that brake pad down onto the table and not use the vise.


I'd use a flycutter as well as clamping directly to the table.  IMHO it's best to avoid vises when possible.  Everything you put between the work and the table adds error.  Looks like that part could be held by a couple of toe clamps.


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## JimDawson (Jul 18, 2016)

:+1: What John said!  Clamp that pad directly to the table.  In fact you have some nice mounting holes there, I would screw the pad down to a tapped aluminum plate that is bolted to the T-nuts with flat head screws.  Align the hold down screws with the T-slots.  I also would use a cutter that was wider than the pad, like a fly cutter.


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## gubni (Jul 18, 2016)

I ordered a fly cutter. What rpm should I turn? What is a toe clamp?

Since I use the same pad all the time a custom mount may be a good idea. 

I have a friend with a dial indicator that I can borrow to test the table.

Does this forum have a for sale section when I can buy second hand from members? I looked, but didn't see anything. Maybe because I don't have enough posts yet or maybe nobody is selling, lol.


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## JimDawson (Jul 18, 2016)

gubni said:


> I ordered a fly cutter. What rpm should I turn?



I would try about 300 RPM to start, maybe 0.010 depth of cut to start



gubni said:


> I have a friend with a dial indicator that I can borrow to test the table.



You can pick up a dial indicator at Harbor Freight, just down the road from you on 321, behind the Sonic Drive In.  On sale now for $17, not the greatest, but they work.



gubni said:


> What is a toe clamp?



Toe Clamp





gubni said:


> Does this forum have a for sale section when I can buy second hand from members?



H-M Classifieds:
http://www.hobby-machinist.com/classifieds/
.
.


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## John Hasler (Jul 18, 2016)

JimDawson said:


> What John said! Clamp that pad directly to the table. In fact you have some nice mounting holes there, I would screw the pad down to a tapped aluminum plate that is bolted to the T-nuts with flat head screws.


And use the same flycutter that you are going to use on the pads to surface the plate.


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## gubni (Jul 18, 2016)

I found this video which really helped in understanding how to use clamps.






Then I clamped it like this and got a much more level cut. The vice was the main problem.


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## John Hasler (Jul 18, 2016)

Better, but the pad is going to bow up a bit in the middle.  Leave out the spacers and clamp *directly* to the table.  Does the pad face need to be parallel to the backplate?  Those pieces you are using as spacers are not precision ground.


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## gubni (Jul 18, 2016)

Yes it needs to be parallel front and back. I thought about it bowing also. I can't go directly because there are bumps on the back of the pad. I do not have a set of real parallels yet so I thought that might work for now.

Where should I buy a set of parallels? Which ones should I get?

Also notice how my clamps are in the t-slot? It seems like there would be a better way to set them up, but I couldn't think of one.


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## brino (Jul 18, 2016)

If you had flat plate to bolt the pads down to, you could cut pockets or drill holes for the "bumps" on the back.

I'll often use flat steel scraps (say 1/4" thick) under the step blocks, so that they are not sitting on the edge of the t-slots.

-brino


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## gubni (Jul 18, 2016)

I feel bad for asking so many silly questions. When you guys answer the answers are obvious. Thanks for all the help.


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## brino (Jul 18, 2016)

One of the biggest rules here is that there are no silly questions.
Keep asking anything you like.
I always learn something from all the varied responses.

-brino


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## John Hasler (Jul 19, 2016)

gubni said:


> Yes it needs to be parallel front and back. I thought about it bowing also. I can't go directly because there are bumps on the back of the pad. I do not have a set of real parallels yet so I thought that might work for now.
> 
> Where should I buy a set of parallels? Which ones should I get?
> 
> Also notice how my clamps are in the t-slot? It seems like there would be a better way to set them up, but I couldn't think of one.


Move your parallels out so that they are directly under the ends of the straps to eliminate bowing.  If you do many of these it will be worth your while to make a pallet (the plate Jim mentioned).


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