Thread: The old "trimming the mill" question

Originally Posted by Oldneweng

I guess he just thought it was a good thing to do and enjoyed doing it. Maybe he will make money selling adjustable parallels. If a parallel is adjustable, it isn't parallel is it?

Dean

Dean, no need to re-invent the wheel. This is what my adjustable parallels look like:

zoom_Starrett_154C_Adjustable_Parallels_17.5-24mm.jpg
PS: They come in sets of different sizes and are not intended to be used in pairs. But they are great to support small workpieces in the vise. Certainly better than stacking up pieces of scraps when you cannot find the right height in the proper parallels box....

Originally Posted by cba_melbourne

Dean, no need to re-invent the wheel. This is what my adjustable parallels look like:

zoom_Starrett_154C_Adjustable_Parallels_17.5-24mm.jpg
PS: They come in sets of different sizes and are not intended to be used in pairs. But they are great to support small workpieces in the vise. Certainly better than stacking up pieces of scraps when you cannot find the right height in the proper parallels box....

Yes, I have seen them, but that wasn't what I meant. I have just been watching a Tubalcain video where he does the "What's in your Box" thing. He showed a square the was adjustable so it was not a square! That's where my comment originated. Anyway, Stuart covers it.

Dean

Originally Posted by Oldneweng

He showed a square the was adjustable so it was not a square!

P1010988 (Medium).JPG

Toolmaker's or Diemaker's square - good for checking draft angles etc.

Michael

Originally Posted by Michael G

P1010988 (Medium).JPG

Toolmaker's or Diemaker's square - good for checking draft angles etc.

Michael

Not quite that fancy Michael. This one was just for transferring angles as far as I am aware. No measurements. I believe he did mention it was good for diemaking.

Dean

We are way OT, sorry Hutcho, but the only thing i found interesting about that presentation is the case hardening recipe....

Ew

Thats OK Ewan. Its all interesting reading. And I learn from the off topic stuff too. I have been trying to get a dial gauge to run on my table while I run it full travel. It looks as though the table doesnt give any runout at all. Nothing to talk about anyway. I am not overly happy with the rigidity of my gauge so will work on that. The vice however, is another matter. I am using basic measuring techniques here guys so dont jump too hard on me. The vice at the top of the fixed jaw on one end is about 4 thou higher than the other end. The bed that the movable jaw runs on is even further out, one side to the other. So my vice may be the culprit. I'll keep on it though.

regards

Old Hutcho

Old Hutcho,

What is the problem you are trying to fix?

Stuart

Stu, I bought a fly cutter and made a light pass over some aluminium square stock I had laying around. The lead side of the cutter did a neat job and then as the trailing edge of the cutter passed on to the job it started to make another cut. (If that makes sense) So it looks to me that the job is not at 90 degrees to the spindle. I believe that as the lead cut is made the tool should not be making another cut on the trailing side of the tool. It should maybe leave the slightest tool mark?

So I am chasing why. My table looks to be level when run past the spindle mounted clock.

Thanks for the interest.

regards

Old Hutcho

Sounds like it could be tram.... but did you try taking another cut in the reverse direction?

Stuart

Originally Posted by Old Hutcho

My table looks to be level when run past the spindle mounted clock.

Yes it probably would, to check for tramming, you need to rotate the spindle.

Imagine the table is tilted by 45 degrees, and you run the table back and forwards past the spindle, the distance between the spindle and the table won't change.

Ray

Something like this..

tramming.jpg

Originally Posted by RayG

the distance between the spindle and the table won't change.

*shouldn't*

Originally Posted by Stustoys

*shouldn't*

Yes of course.. but then again Hutcho said it didn't..

Ray

Originally Posted by Old Hutcho

The lead side of the cutter did a neat job and then as the trailing edge of the cutter passed on to the job it started to make another cut. (If that makes sense) So it looks to me that the job is not at 90 degrees to the spindle. I believe that as the lead cut is made the tool should not be making another cut on the trailing side of the tool. It should maybe leave the slightest tool mark?

Yes...and no.
If the spindle were perfectly square to the table and your machine was perfectly rigid then you would get a mixture of marks as neither one side or the other would predominate. If your spindle is not square then you will get one side and not the other. When rigidity is taken into account, the cutter can bend away from the direction of travel which can also complicate things. That will then give the impression that the spindle is not in tram when it is. Light cuts are needed. Nothing says that your mill must be spot on in tram by the way, but if it is not then a milled surface will be a series of scallops perpendicular to the direction of travel. (One well known UK writer used to purposely have his mill head slightly off tram so he didn't get the mixture of marks.)

One thing you may like to check is how parallel the vice base is to the machine table. On a good vice (new) you can rely on it being pretty good but on a cheaper unit or second hand unit it will not be. A skim across the base of the vice may be in order if it is not parallel.

Michael

Originally Posted by Old Hutcho

Thats OK Ewan. Its all interesting reading. And I learn from the off topic stuff too. I have been trying to get a dial gauge to run on my table while I run it full travel. It looks as though the table doesnt give any runout at all. Nothing to talk about anyway. I am not overly happy with the rigidity of my gauge so will work on that. The vice however, is another matter. I am using basic measuring techniques here guys so dont jump too hard on me. The vice at the top of the fixed jaw on one end is about 4 thou higher than the other end. The bed that the movable jaw runs on is even further out, one side to the other. So my vice may be the culprit. I'll keep on it though.

regards

Old Hutcho

See my thread about "Two Thou". I've been scratching my head for a day or so about this one. Like you I get virtually no variation from one end of the table to the other. But my vice bed is also dead parallel to the table. In my case after skimming the top of the vice jaws I get this "Two Thou" difference across the 4" jaw width.