Quick Change Toolpost

A quick change toolpost based somewhat loosely on the design that Vikki built. I had already bought the steel for the post, so I decided to make it out of steel rather than aluminum. Not that it took any longerÖ.

 

 

Starting off with a 2.5 inch square piece of 1018 steel, mainly because thatís most of whatís available. I overdid the milling a bit, and finished all the surfaces. Itís about 1 1/2 inches thick. The next step is to decide on the location for the dovetail, how many, and where to put the holes.

 

The location for the dovetail was placed squarely in the middle of the length of the toolpost. This slot is about 1/4 inch deep, which is all the dovetail that a 60 degree dovetail cutter 1/2 inch in diameter will do.

Youíll notice , in the second picture, a bright slot where the dovetail starts. Iíve decided to blacken the metal to be removed with a marker. This allows me to see where Iíve yet to go. I was very conservative, and removed only about 10 thousandths each pass. This took quite a while.

However, I decided that before I did all this, I would try out the dovetail cutter, see how well things worked, and make some gauges in the process.

 

Hereís the edge marked on the gauge. The countersunk hole is because Iím cheap enough to use aluminum over again, and it wonít matter that the hole is there. You can see Iíve got just a little more to do for this dovetail on this side.

 

Hereís the two gauges. They fit well enough that they are a snug fit when you try to pull them apart. Thereís enough friction that it is difficult to move them up and down when trying to pull them apart.

 

The two gauges trimmed so that they look like theyíve been made for each other. I meant to do thatÖ.

 

 

The toolpost with the dovetail almost milled. You can see how easy it is to see the part that has yet to be milled. Once I get close, I start trying with the gauges, and I also look at the width of the slot. Note also that the dovetail cutter is milling out the flat surface, and doing a nice job of it.

 

Last pass. The gauge fit and the dovetails are done for the toolpost holder.

 

I tried to find a good way to hold down the tool carriers, and finally settled on drilling a 3/8 inch hole through the 7 inch long steel bar. Using the jacobs chuck made the setup too flimsy, but when I tried to use the collets, the tool wouldnít reach far enough down.

 

Time to stop everything, replace a gear that had been mistreated, and do the torsion arm mod. You can see the old hole below the attach point of the arm. The spacing is about 1 inch. Iíd rather have done it about 1/4 inch further up, but the results (in the second picture) were good enough.

 

Youíll notice that thereís enough travel so I can use the collet. It was worth the effort to move the torsion arm.

 

This is the last bit of the dovetail. I got rather tired of it, and started using an electric drill set to very slow to turn the feedscrew.

 

The tool carriers are finally milled. Now to keep doing stuff that wonít ruin the effort. There was enough space to make 4 carriers out of this, and throw away the two sections with the holes.

However, I decided to try to make something out of the other sections, and looked at my knurling tool.

But first, some pictures of how I decided the whole thing would fit.

 

As it turns out, I had to use the chuck for the dovetail cutter. Not happy, but it worked. The nice blue block is the toolpost sitting on one end.

 

And the toolpost is sitting on the other end, so unless Iíve managed to make it odd shaped, it all works.

 

Iíve cut the pieces to size, and realized that these pieces are awfully thick. I could have gotten a piece of steel a little less thick. Still, it turned out well. I could cut all these on the metal saw.

 

 

Before I did that, though, I tried to see how this would fit. The toolpost hangs out over the left edge of the compound by 1/2 inch, and goes in by the same amount. I could trim off that inner 1/2 inch, but the one to the left with the tool carrier has to stay.

 

As you can see, cutting the half inch off the tool carriers could have been a real problem, but I had something that would fit in the metal sawís vise, and would also hold the tool carriers securely. There was enough pressure to lock the carrier in place.

 

 

All the carriers cut to size. Boring bar to left, 1/4, 5/16 lathe tools, circular boring bar, two more lathe tools, 5/16 and 3/8. The toolpost is to the right.

 

The handle and threaded rod are from the original toolpost, and the small washer next to the handle keeps the handle at the proper angle when locked. The handle above the cam goes on the cam, and the cam plate, locking screw and washer are above the tool post.

 

This shows the tool post block with the hole for the cam and cam plate. The cam goes in the front of the toolpost. The hole was drilled first, and the cutout for the plate was made second.

 

The cam installed in the toolpost. Thereís a small flat milled on one side so the plate will lock into place, although that doesnít always happen. The hole below the cam is for the locking screw, more on that later.

 

Hereís the cam. You can see that the cam area is wider than the hole for the plate. Thereís a small flat milled on the cam for the handle, which keeps the handle from slipping. The end is slightly pointed, which probably wasnít needed, but looks nice.

 

The cam plate itself is beveled on each corner so I didnít have to make an absolutely square hole for the plate. While it may be hard to see, thereís a little protrusion on the bottom of the plate. Itís small enough to fit into the hole that the cam fits into. This small part rides on the cam.

 

This last photo just shows the position of the cam in relation to the tool post. The darker area on the plate is the area the cam rides on.

 

This gives the best picture of the cam plate with the cam installed.

 

Hereís the face view of the cam plate. The screw is a 10-32 socket head screw. One of these days Iíll get a set of counter bores for this, for now, itís just a drill. The screw holds the plate in place, but is left loose enough that the plate can move.

 

Hereís the handle for the cam. The handle itself is made from a 5/16 inch bolt with the head removed. No sense in making what you can buy for cheap.

 

Hereís the boring bar holder (the square one) as finished, but without clamping screws. Thereís about 1/16 inch clearance top and the tool is also inset by the same amount.

 

I bought a knurling tool, only to find out that it would not fit the lathe. Not happy, I wasÖ. You can see the reason, the arm is far too long, even on the new toolpost. However, suppose I didnít need the arm? I had a carrier that had a hole already in it. Just needed to thread that thingÖ.

 

The hole was too big to thread. So I milled a small slot in the dovetail, and turned a nut down to fit into a larger hole that had been counterbored. This is the carrier before it has been cleaned up.

 

The knurling tool, an added nylon washer, the carrier, and the nut. You can see how it was turned down to fit in the hole. The top part keeps the nut from falling through and also locks it into place. If it ever breaks, itís easy to replace.

 

Very cleaned up, you can see the slot for the nut in the back. Thereís still plenty of surface for the cam plate to push against. The carrier has been finished on a belt sander, and the edges have been rounded a bit. The whole assembly will be blued, but later.

 

Top view of the carrier. Plenty of surface left on the dovetail.

 

This shows the position of the knurling tool. It fits quite nicely, and just happens to fit the way it should. Thereís no height adjustment because the height adjustment is just an eyeball measure, anyway.

 

The knurling tool in action on a scrap of aluminum.

 

Hereís the top view. Everything lines up quite well, and I am surprised, but happily so. Thereís enough adjustment in the cross slide to accommodate all different sizes of work.

 

Hereís one of the toolposts, finished, blued, and with the height adjustment in place. None of these are exactly the same height, but it really doesnít matter.

 

Hereís the second. I made one that was for 5/16 inch tools, one for 3/8 inch tools.

 

Hereís the one that I left the original thickness, so something good came of that. This takes 1/2 inch boring bars, and the slot was made with a slitting saw, just a little at a time.

 

Another view of the knurling tool, blued and ready for use.

 

In case the idea of the height adjustment never quite struck home, here it is in operation. The screw is another 1/4 by 20 bolt, the capscrews are all metric so they fit whatís on the lathe, and the knob is knurled with the tool above.

 

Hereís the toolpost, blued and in place. The plate was aluminum, so that didnít blue. This shows the plate fully extended with the handle in the locked position. Everything turned out rather well.

 

Hereís the entire ensemble. The various toolholders are shown together with the toolpost. I donít think I have enough toolholders, but that will wait until I get the energy to go ahead and make another somewhat long project out of the tool holders. Iíve got enough for now, and the toolpost itself is removable rather easily.

 

If I were to do this whole project over again, I might make the toolpost a bit smaller towards the center of the lathe. It has cost me a little cross slide travel, but not much, only half an inch.

The cam mechanism seems to be a bit more complicated than it needs to be, but Iím still working towards elegant simplicity. Itís a goalÖ.

Bluing worked reasonably well, but Iíd rather have had true blue rather than black. I do think that two treatments was probably needed, but Iíll see how this wears and reblue as needed.

I drilled one of the setscrew holes before I bored the hole for the knob, and found that the drill ran off center by a lot. Strange that it did, so I left that Ďtill last, and it worked much better.

Weíll see how this works in practice, but considering the mass of steel, it should be just fine.