Rebarreling and Home-Shop Machining

1 inch Stock Preparation

My slotted plate to which the cross arm will be attached will be bolted to 1 inch square solid stock supports that are welded to the fifth column. This photo sequence shows the preparation of this 1 inch stock.

Flycutting the Surface

First I took a milling cut on front and back of the stock using a fly cutter with a similar clamping arrangement to that shown in photo 3, with the exception that I had a third middle clamp that I removed to complete the middle. I then replaced the middle clamp and removed an end clamp to Mill the ends. Even this thick stock had some curl to it after a milling cut on only one side. This clamping method helps to hold the stock flat better than using the vise. I then reversed the stock and took a milling cut on the back. The front was now pretty flat. I used the fly cutter to remove the hard scale of this hot rolled steel without wear to a good endmill. I used the fifth column to support the mill head with some makeshift clamps. The milling performance was much better than before the fifth column. A lot more solid hits without the bounce on this 2 inch diameter fly cutter. Good sized smoking blue chips were produces.

Layout

Photo 1 shows the layout of the milled and sanded stock which has been sprayed with Dychem layout dye. This is a medium precision part so I did the layout on the drill press table using the Combination square, the scriber that fits into the casting of the square, a small Starrett automatic center punch and magnifying glass to punch the cross points, and a larger center punch to provide a good starting point for the big drills. Care here will improve the appearance of the part.

Drilling

I drilled and counterbored the holes on the drill press. The mill could be used as well. The photo shows the proper orientation of the drill press clamp. The base is used as a stop to prevent the work from rotating when the bit breaks through the work. The force is considerable on these big drills, so this is more important. I added a second stop with a T- nut underneath and a bolt and spacer that came with my mill clamping kit.

I first used a ½ inch drill to drill through the work. Photo 2. I then replaced the drill with a 3/4 inch drill. I used the stop, on the drill press feed, to counter sink the hole ½ inch for the head of my socket head capscrew. To use the stop on this Delta Drill Press, I put the larger drill bit down with the feed handle until it touched the edge of the hole; the tip was below the surface. In this position I rotated the stop until the ½ inch division was on the indicator line and locked it down with the thumb screw. The feed then will stop when 0 is reached. A ½ inch deep counterbore will be produced, but with a tapered bottom. This removed most of the material from the counterbore with a less expensive and easier to sharpen tool than the endmill used below.

Milling Counterbore

I then put the work on the mill to finish off the bottom of the counter bore flat. I used paper to find the top surface of the work. I adjusted the hole centered on the 3/4 inch two flute mill by eye. I used a dial indicator (on the top of the drawbar that secures the endmill holder) to controlthe down feed, to mill to ½ inch depth. Photo 3 shows a finished counterbored hole. In the back ground a flush fitting socket head capscrew is shown in a finished hole. Another screw is shown on top of the work. A postit pad paper makes a good tool for finding the top of the work.

Note that a piloted counterbore is available to drill a flat bottomed counterbore in one pass. The one that I saw in the Cambell tools Catalog has a 9/16 inch shaft and drills a 25/32 inch counterbore and is available for about $20.

1 inch Bars Ready to Weld

 I first Clamped the 3/4 steel plate to the face of the cross arm with a bar across the assembly and then a .25 inch wedge at the face of the cross arm but behind the plate. Photo 4. I then clamped the bars to the plate. Two studs with barrel nuts are being used as screw jacks to hold the assembly together now. Photo 5 and 6 show the lathe side and outside of the one inch bars ready to Weld. Photo 7 and 8 show the 1 inch bars welded up.

Quadralift Stop/Screw Jack

I adjusted the quadralift downward to its final position to do the fly cutting described above. To improve rigidity and to prevent slack from building up on the quadralift, I applied light tension upward with this small screw jack. The jack accepts the standad 3/8 studs from my clampingkit so that I can make it to any height longer than the red base itself. Photo 9.

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