Tool Post Holder

You can make these anyway that you want to. Doesn't seem to matter. I have done several different styles. I have found that you don't need the 45* angled cutout. I made the cut outs with an end mill. Nothing special. First milled out the flat portion. Then clamped the holder in the vise at a 45* angle and milled the angled portion. Just leaving it squared off seems to tighten just as easy as with the cutouts. I will not make the cut out in any future holders that I make. Takes 1/4 turn with the wrench to go from loose to tight.

5/16 bolts are the smallest you can use. I tried 1/4 bolts and twisted the head off trying to get it tight. 3/8 bolts work the best. If you do make the cut out you have to be very careful with the position of bolt. You have to have enough clearance for a wrench to fit on the bolt.

I have found that 1/4 set screws are sufficient to hold the tool bits. I used 5/16 set screws to start with. The most recent ones that I made have all been 1/4 set screws.

After Mikey schooled me on the forces and geometry of parting I made a special holder for parting. It sits on the base. No height adjustment screw. I used to be parting challenged. With my new parting holder no more problems with parting. Winky's Workshop has good videos on making a parting tool holder. I followed his design.

I found that you need a nut on the height adjustment screw to lock it in place. Otherwise it will move with vibration and handling so you loose your height and have to reset the height. And you have to be careful with the position of the height adjustment screw so that you can get a wrench on the nut to tighten it. You also don't need a 1/4 screw. There is no load on the screw. A 10/24 screw will work just fine.

I have made 12 holders so far and plan to make a couple more. Including a knurling tool based on Mikey's design.

IMG_3637.JPG

IMG_3767.JPG IMG_3908.JPG
 
AmericanMachinist said:
I am planning to make tool holders of this style. Thanks @mickri for posting the full PDF scans of the article in the original post.

What tool would you use to cut the 45* bevel shown on the rear-left of the tool holder bodies (top-left image)? I pictured using an end mill with a 45" cut and a flat bottom cut, sort of an inverse-dovetail cutter. But I'm not seeing these on McMaster.

I'm also considering flipping the design when applied to boring bar-type holders, so that the cutout, the height-adjusting screw, and the body-tightening bolt are all on the right-side of the tool post rather than the left. This in my theory provides the benefit of allowing me to use my right hand to tighten and loosen the body-tightening bolt. Because I plan to add indexing detents to base, I don't foresee a complex 2-handed operation to install the tool holder.

Am I missing anything in making that change?

Thanks!



View attachment 352932
Click to expand...

Couple of ways to approach that bevel. If it were me, I'd save it for last, tip the part in the mill vise on edge at a 45 degree and use a normal endmill to cut it. You could also use a swivel vise.

There are also chamfer cutting endmills. One type is called a drill mill and is a normal endmill with a 90 degree point on the front. The other kind is more for doing small chamfers, but you can make it work if you take your time.


Chamfer Cutters-Pointed & Flat End

www.harveytool.com www.harveytool.com
 
Thanks! are yours roughly 2x2" 1018? Or similar? 1-1/4" post it looks like? I need to order materials one evening soon and want to make sure I size mine so they lock with a quarter turn as you mentioned yours do.

Thanks
 
The first batch that I made was out of 2 1/4 x 1 1/4 1018 bar stock. I brought it online. The shipping cost as much as the steel. The second batch that I made was out of 2 x 1 1/4 1018 bar stock that I got from local machine shop. Still have some left to make more tool holders. I have been in there several times since and no matter what I buy I pay $30. Works out to be under $.50 per pound. Most of my holders are 2.5 L x 1.25 H x either 2 or 2.25 W. The center hole is 1.25 ID. The only critical dimension is the holders need to be a very close fit on the post. Within .001 to .002.

Have you read my thread where I summarize making my tool post and the holders? Norman style QCTP | The Hobby-Machinist (hobby-machinist.com) I go through everything that I think you need to know to make a Norman style QCTP.
 
I use lengths of #6-32 all-thread for the height adjuster to get a little more control over the height adjustment. I smooth the bottom so it doesn't scratch the top slide. As micri said, the height adjuster doesn't carry any load so you have a lot of choices there.

This style of QCTP accommodates many different approaches. Hence all the different versions you see out there; and most users seem to be happy with the final product. I like mine, not least because it's relatively easy to make whatever you need.

Mine is mounted on a relatively small lathe that can't take really deep cuts anyway so I make my toolholders out of 6061 aluminum rather than steel. Even the parting tool holder works just fine for me.
 
Add a handle so you don't have to look for a wrench every time you tighten. You can easily just weld a piece of steel bar to the head of the bolt also.
toolpost1.jpg
 
I thought about making handles but decided not to because I would need a handle for every tool holder. I have been thinking about going to square headed bolts with the head the same size as the wrench for my lathe. I will probably try one to see how I like it before converting all of my tool holders over to square headed bolts.
 
You must log in or register to reply here.
Back
Top