# Tramming a Harbor Freight mini mill



## maddthom (Oct 11, 2020)

I am brand new to hobbyist machining, I've bought a Harbor Freight mini mill and a Morphron 7 x 14 mini lathe, I didn't have the money to buy anything better.  A machinist gifted me a Mitutuyo dial test indicator to measure and loaned me a Brown & Sharpe test indicator, I have a couple of questions I hope someone can help me with tramming or squareness, and if I'm posting them in the right forum. 

1.  the mini mill, the head is not square to the column, I've gotten the column square to the bed(I think, see question 2) but do I need to shim the head? or does it matter that the head is canted about .02" / .5mm (I'm an American but its easier for me to use the metric system than fractions, the Mitutuyo is metric)

2.  I think I've gotten the column square to the bed BUT when I turn the beds Y axis the needle on my indicator moves, to me it seems like the bed is tilting, also when I measure along the X axis I get different measurements from front to back, again its seems to me that bed between the T-slots isn't level/height or I'm I doing something wrong?

3.  I understand that I have the cheapest machines but what kind of accuracy should I expect?  Just adding a little context, I've taken both of my machines apart trying to get them completely square or am I trying to do something that is not possible?

4.  I've looked but I haven't found a guide to tramming a mini mill or lathe, is there one?  If someone knows were I could find one please give me a link, thanks

If anyone could help me I would greatly appreciate it, if any one has any tips, advice or links to tutorials I would love to hear it but thanks to anyone trying to answer my questions.


----------



## addertooth (Oct 11, 2020)

You might give this article a shot.

https://www.hobby-machinist.com/threads/shim-free-tramming-of-mini-mill.30182/

There are also 3 videos I found on Youtube on "tramming a mini mill" via a google search.














There may be some Continental accent in the videos.


----------



## addertooth (Oct 11, 2020)

Maddthom,

Please forgive my manners. I see this is post number One for you;  I was remiss in offering a welcome to the forum.  
Do give a thought of going to the "*INTRODUCE YOURSELF & WELCOME NEW MEMBERS" *forum
and telling us a little about yourself, and your new equipment.


Other than charter members of the deep-pocket club, many here started with smaller equipment than they sport today. 
Most of us smile because we know the journey you are about to undertake.  Assuming you stick with it, you will likely
upgrade and increase the size of your equipment over time. You may even fund the upgrades via producing some 
gizmo on the equipment you have today (but that is an Entirely different topic).

With small equipment it can be harder to get great results without experience.  An old salt can walk up to a mini-lathe/mill
and produce solid results. He knows how to compensate for what limitations and challenges which may exist in smaller equipment.
 A person with less experience will INITIALLY produce parts of questionable virtue on mini-equipment.
But, as they master feeds and speed along with tool grinding, they eventually start producing good parts; don't get discouraged.

I cannot under-state how important it is to put a bit of sweat equity into inexpensive equipment.  Often finishes on the equipment are a big rough, may have burrs which affect accuracy and trueness.  You may find that things are just out of alignment (as you have). This can
force you to dive off the deep end into "metrology" to set your new equipment to "true".   

Start out with easy metals, such as aluminum or brass.  Steel, especially cold-rolled steel is tougher to get great results with initially,
and it may discourage you. Finding a source in your area for "non-mystery" metals is helpful too. 

Best of luck to you.

             Addertooth


----------



## maddthom (Oct 11, 2020)

Thanks I really appreciate it, but I've seen those videos and that article and they didn't help.  I've not seen anything about a tramming the head to the column, again my machines column is square to bed with the X and Y axis locked, the head is not square to the column, I could just shim it but you have to disassemble the entire head to do so then reassemble, measure and repeat but I don't know if thats the correct thing to do or if its necessary, does the canted head matter? The Harbor Freight mini mill has a tilting column, it has a single 32mm nut, T bolt and squash washer for tilting and that mounts to the base with 3 bolts, the bolts are in a almost straight line and it acts like a pivot point, I've seen someone take .5" steel plates and weld them into a L shape to mount to the base and column to it to make it more rigid but I don't have the steel or a welder.  But thanks again.


----------



## addertooth (Oct 11, 2020)

I can be of little help on truing/shimming the head itself.  I am not familiar enough with the model of mini mill you have. 
Virtually all of the mini-mills of that family (harbor freight, Grizzly, etc)  are made by a company called Sieg (or close clones to the Sieg). I know there
is a wealth of information out there for those models.

For some general rule of thumb, shims are appropriate IF the surface shimmed is static, i.e. does not slide on the shimmed surface.  Any sliding or rotation on a shimmed surface tweaks the trueness each time it is moved.  This is why the base of the column is a favorite place to shim.  However, if the column is perfectly vertical, but the head is at a strange angle, I would be tempted to true the column face where the head attaches to the column, or true the face of the head where it mates to the column (you would need to figure out which of the two was mis-machined).  But then, you are getting into the whole "you need access to a bigger mill, to fix your smaller mill" which is not always reasonably available.

As for error, "canting" I normally try to express the error in the impact on the part you are working on.  If a 6 inch long part is 1/1000th of an inch thinner on one end, than the other end, I express the error as 0.001 over 6 inches. If something "looks strange", but cuts true parts (and flat cuts Without dishing), then there is little harm (other than to my emotions).


----------



## maddthom (Oct 11, 2020)

I'm having fun just trying to set the machines up.  I think, but I need to double check, that the head is canted to the right, not nodding, does that matter?  But if it does, the guy that gave me the Mitutuyo indicator has a Bridge Port and told me to come anytime I need to use it.


----------



## addertooth (Oct 11, 2020)

And remember, a head is not nodding, unless it is locked and nodding.  It is well understood the play in the gibs can make the head nod and cant until it is locked (tightened) in place.


----------



## markba633csi (Oct 11, 2020)

Maddthom: If you can post some closeup pictures we can give some more detailed advice on what you might do to improve the situation
Cheers,
Mark


----------



## mickri (Oct 11, 2020)

Welcome to the forum.  You will get good answers to any question you might have no matter how simple the question may be.

If I understand what you have done so far is that you have squared/trammed the column to the table and now you are trying to square/tram the head to the table.  I think that is the wrong approach.  It doesn't matter if the column is square/trammed to the table.  What matters is that the head is square/trammed to the table.  That is what is important.  The accepted way to do this is to place shims between the base of the column and the table.

Again welcome to the forum.  The really knowledgeable people on here will help you get your mini mill dialed in.


----------



## higgite (Oct 11, 2020)

mickri said:


> If I understand what you have done so far is that you have squared/trammed the column to the table and now you are trying to square/tram the head to the table.  I think that is the wrong approach.  It doesn't matter if the column is square/trammed to the table.  What matters is that the head is square/trammed to the table.


With all due respect, it does matter if the column is square/trammed to the table. If it isn't, the head will not move straight up and down relative to the table, but will shift along the X and/or Y axes as it moves up and down. A long jobber drill, for instance, will not align with a starter hole made with a short center or spotting drill. The actual amount of offset might be inconsequential to the operator or the operation, but it will be there.

Tom


----------



## homebrewed (Oct 11, 2020)

There are some web pages describing how to align the head to the column on a mini mill.  Here's one, and this one is a little more detailed.  BTW, you don't need to remove the column in order to evaluate how bad (or good) the alignment is.   I evaluated my mini mill and decided that it was good enough for most of my needs.

The author of the first first link talks about using a special test bar ordered from McMaster-Carr, but any accurately ground rod will do.  The author of the second link used a rod scrounged from a printer.  I have some linear shafting I use for this, it's available for cheap on ebay.  1/2" drill rod would work OK, too.  You don't want a rod that is small enough to be significantly deflected by the force of the dial indicator plunger....but if using RDM that may not matter.

Unfortunately, the mini mill design doesn't have a built-in way to adjust the alignment.  You have to use shims on one axis and hope there's enough rotational slop in the other to get to where you want to go.


----------



## maddthom (Oct 11, 2020)

Thanks for the response mickri.  No, I'm not trying to tram the head to the table, I would have done that next, I'm trying to tram it to the column and I found that the head is tilted to my right.  I put a dial indicator in a collet, swung it to my right, while facing the machine, turn it so its touching the left side of the column,  swing it to the oppisite side and the indicator is .02" or .5mm lower/deeper or if I have the indicator barely touching the left side of the column swing to the right hand side of the machine its not touching the column.

Just to give more context, I took the machine apart to lift it onto my bench(hurt my back in the Army in the late 90's needed to split it to pick it up), I then tried tramming it.  I could get head trammed to the table, that the column was not tilted left or right but if I moved the X or Y axis my measurements were way off not even close to being the same.  So I started trying to tram every part that moved or I took apart, thats when I noticed that the head is not square to the column.  If it was, I would have moved on to tramming the head to the table but I thought I should ask for some advice before I ignored the tilt or shimmed it.  The head and motor mount to another block with 4 bolts, that second block mounts to the column, so the head does not move in relation to the column, moving the head up or down does not change the tilt to my right, the measurements do not change, so could I ignore it?


----------



## maddthom (Oct 11, 2020)

Thanks homebrewed, but thats not what I'm trying to describe.  It seems to me that the 2 casting that make up the head are angled to my right, I measured it by puting a indicator in the spindle with a collet measing the distance from the spindle to the left hand side of the column then swinging it the the right hand side of the column and getting a difference of .02" or .5mm further away on the right hand side.  But I do have some old rods from printers and will use this to measure the nod, thanks again.


----------



## mickri (Oct 11, 2020)

Higgite I hadn't thought about that and have not experienced that on my round column mill/drill.   I use what I call the longest tool method as described by the Lazy Machinist in one of his videos to set the height of the head.  By doing that so far I have not had to move the head to change tooling on my round column mill drill.  Maddthom does not have a round column.

Maddthom  I think that this is what you are trying to achieve.  https://www.homemodelenginemachinist.com/threads/mini-mill-spindle-column-alignment.5337/


----------



## tomfiii (Oct 11, 2020)

How did you tram the column without using the head ?


----------



## maddthom (Oct 11, 2020)

mickri said:


> Higgite I hadn't thought about that and have not experienced that on my round column mill/drill.   I use what I call the longest tool method as described by the Lazy Machinist in one of his videos to set the height of the head.  By doing that so far I have not had to move the head to change tooling on my round column mill drill.  Maddthom does not have a round column.
> 
> Maddthom  I think that this is what you are trying to achieve.  https://www.homemodelenginemachinist.com/threads/mini-mill-spindle-column-alignment.5337/





Thats exactly what I'm describing, and the info I was looking for, thanks mickri


----------



## maddthom (Oct 11, 2020)

tomfiii said:


> How did you tram the column without using the head ?



I don't know if it was a correct thing to do, but I used a magnict base mounted to the table loosened the 3 bolts mounting the column tilting mechinism to the table, cranked the X axis back and forth and tapped the column until both sides of the column read the same.


----------



## tomfiii (Oct 11, 2020)

You need a picture or drawing of what you are doing,as that sounds like squaring column to Y axis.


----------



## maddthom (Oct 11, 2020)

Do I have the axis mixed up, I thought the table moved in X and Y, rasing the head up and down was Z, am I wrong?


----------



## higgite (Oct 11, 2020)

mickri said:


> Higgite I hadn't thought about that and have not experienced that on my round column mill/drill.   I use what I call the longest tool method as described by the Lazy Machinist in one of his videos to set the height of the head.  By doing that so far I have not had to move the head to change tooling on my round column mill drill.  Maddthom does not have a round column.
> 
> Maddthom  I think that this is what you are trying to achieve.  https://www.homemodelenginemachinist.com/threads/mini-mill-spindle-column-alignment.5337/


Mick, I agree. I do the same when I can, just on general principles, but my mill has a quill, as I imagine yours does. Mini mills like the OP's don't have quills so he has to move the head up and down for drilling, plunge milling, etc., so an "in tram" column is actually more important to him than it is to us. Adding to his woes is the HF mini mill has a tilting mechanism so the column can be tilted left or right for angled drilling, etc., and it has to be re-trammed when you "untilt" it. Theoretically, the head should be aligned with the column from the factory and not need separate tramming, but Murphy is alive and well.  

Tom


----------



## higgite (Oct 11, 2020)

maddthom said:


> Do I have the axis mixed up, I thought the table moved in X and Y, rasing the head up and down was Z, am I wrong?


You are correct, side to side is X, front to back is Y, up and down is Z. You are trying to tram the Z-axis to the X and Y axes.

Tom


----------



## maddthom (Oct 11, 2020)

Thanks Tom, sorry if I confused anyone because I didn't know how to phrase it.  Your reply to Mick, your right I'm sure you know alot more about them than I do but the tilting column isn't the only problem, that tilting mechanism mounts to the base with 3 bolts they are almost in a straight line so it acts like a pivot point with side to side movement.  Thats the reason I was slowly taking my time with every, part that can move, trying to make sure it was a square, but thanks to everyone who responded btw Does any one no of a way to make them more rigid?


----------



## tghsmith (Oct 11, 2020)

there is a reason why little machine shop sells a non tilting conversion column,,(they also sell replacement gears or a belt drive conversion kit)


----------



## mickri (Oct 11, 2020)

There have been lots of methods tried over the years to add more rigidity to a tilting column mini mill.  They all add supports to lock the column in place.  Do some searching online and you should find numerous possible solutions to try out.


----------



## maddthom (Oct 11, 2020)

tghsmith said:


> there is a reason why little machine shop sells a non tilting conversion column,,(they also sell replacement gears or a belt drive conversion kit)



I've already looked at them and spoken to the people/person that works there, they are extremely helpful its just $300-$400 is beyond me right now, gota work with what I got.


----------

