Tool Post Holder

mickri said:
Nice job on your tool holders. My boring bar holders are are a little on the rough side but work well. Mine also take only a 1/4 turn to go from free to locked. I have been using the two boring bar holders to bore the center holes on the remaining five holders. I have decided to complete one holder as a test run. I will try cutting the slot with just the end mill without drilling out most of the material to see how that works for me. I can hold all of the last four holders in my vise at one time.

View attachment 276819

That way I can cut the slot in two of the holders at the same time. Then do the other two. I have been using the slowest speed on my mill in previous projects. For this I think that I will figure out what speed I should be using and see how that works for me.
Click to expand...

Thanks for the picture. Be very careful holding several pieces like that in your vise. I personally would not do that. You cannot guarantee that the work pieces have faces flat enough to grip each other. At best I would only hold two, and even then use some cardboard between the vise faces to ensure that they were both gripped securely. Also tap them down so that they are sitting flat on the vise bottom.
 
Ok, I got it now. The main body of the holder is NOT split, it's the pin. It makes for a very clean look! I'll have to give it a shot -- slitting the holder is a slow job, at least the way I do it....
 
Hi Guys,

I think that most of the articles that I've seen put a slit in the block and squeeze it with a clamping screw, did it that way because it was easy to write an article for publication without putting people off because it was hard to make. Forty or fifty years ago it would never have been done.

I used to have a copy of the original drawings for the Norman Tool Holder, in those it was a split clamp as in my drawing.
As I mentioned to Mick, splitting the block means that you only have two points of contact on the post. Using a split clamp actually has three, but those contact points cover a much larger area and thus greater rigidity.

One other important point that I have just remembered. When splitting the clamp, make sure to deburr the edges of the cut ! If you don't the burrs will cut into the post and make the movement rough.
 
Started cutting the first slot in a tool holder. 1/2" four flute end mill and 90 rpm. I know probably way too slow but then I am a newby. Depth of cut is 0.010. My mill/drill doesn't seem to like cuts deeper than that. Here is my set up.

IMG_3633.JPG

As I make a cut the table jumps back and forth by the amount of the backlash in the table. It feels like climb milling. Is this normal when milling a slot? Or am I doing something wrong.?
 
mickri said:
Started cutting the first slot in a tool holder. 1/2" four flute end mill and 90 rpm. I know probably way too slow but then I am a newby. Depth of cut is 0.010. My mill/drill doesn't seem to like cuts deeper than that. Here is my set up.

View attachment 277100

As I make a cut the table jumps back and forth by the amount of the backlash in the table. It feels like climb milling. Is this normal when milling a slot? Or am I doing something wrong.?
Click to expand...
tighten the gibs a little?
 
Hi Mick,

As Pacifica says, tighten the gibs, you have too much slap in the table. 90 rpm is way to slow for a 1/2" inch cutter !
Make sure you nip the quill as well, you don't want the cutter to pull the quill or the cutter to pull out of the chuck collet.
As far as depth is concerned 10 thou is barely a scratch.

But since you are learning, try 20 thou (1/2 mm) and see how the machine behaves, increase the rpm's to say 400. That mill has a substantial round column, so if the table is tightened up you should easily be able to do a 2 mm (80 thou) deep cut, which I can do with mine.

Also its nice to see that you have taken my advice about not ganging up workpieces.

Keep me informed about how you get on.
 
I checked my backlash and it was way out. Undid the lead screw on one end and slid the table to one end to expose the lead screw nut. Found that one of the bolts that holds lead screw nut in place was loose. Tightened everything up and my backlash is back to its usual 0.005. In process of tramming the vise and then hopefully I can get the tool holder close to where it was. I don't have to be absolutely exact on the tool holder because I was milling about 20 thousands from my line on one side with lots of room on the other side of the slot.

I'll try the faster speed and deeper cut to see how that works.
 
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