Thread: Magnetic base clamp in sixteen steps

The toolmaker took back his Mercer mag-base, that looked a bit like this:

s-l1600.jpg



For a while I tried to cope with a smaller/weaker base,
but after it fell off something and bent my large plunge indicator, it was time to build a better setup.


I was given a fine adjustment spring rod thingy a few weeks ago,
so I just need a good mounting system. Rummaging around,
I found 50mm generic base with a broken hydraulic arm.

1. Unscrewed broken arm, its an 8mm thread. Grabbed some scrap rod, machined a ~7.9mm step on the end, and used crappy 8mm die to cut the thread
2. Screwed it into the base, then spent way too long, trying to cobble together a clamp from available junk. Decided I would machine a twin disc swivel clamp. Find some cleanish 50mm round, face in lathe:	IMG_1522.jpg
3. Drill through at 11/64, and started 1/4"WW thread: (to match my box of cheap old screw handles)	IMG_1523.jpg
4. Grab in the mill, load 10mm end mill, and machine some flats for accurate drilling: (Spring rod is 8.5mm diameter. and scrap rod ~9.5mm diameter. I sort of just eyeballed slot offsets)	IMG_1524.jpg IMG_1525.jpg
5. Spot drill: (actually a lathe centre drill, because I don't have any real spot drills, but is conveniently 10mm diameter, so no collet change required ! )	IMG_1526.jpg
6. Drill both thru at 8.5mm:	IMG_1527.jpg
7. Enlarge one to 9.5mm: Made some colourful swarf !	IMG_1528.jpg IMG_1529.jpg
8. Back into the lathe for parting off. First, rotate/align parting tool to the job: (which is hard against the chuck face)	IMG_1530.jpg
9. Then, use side of tool for aligning job in chuck: (my chuck is bad, and this saves me dial indicatoring)	IMG_1531.jpg
10. Part off between discs. This didn't go well. There wasn't quite enough space between the holes, so it was an interrupted cut, which killed my insert. Finished off with hacksaw:	IMG_1540.jpg IMG_1549.jpg
11. Face off, and check the rod still fits: (I was worried the lathe might have pushed the material in at the edges)	IMG_1550.jpg
12. Load the other disc in the chuck: Using two parallel-ish rods as spacers	IMG_1551.jpg
13. Face this one off: On this one, I barely cut into the hole	IMG_1558.jpg
14. De-burrrr: (and then I filed the edges also)	IMG_1560.jpg
15. Finish up the thread. Mag base and rod comes in handy:	IMG_1562.jpg
16. Drill other disc thru at 1/4", find a washer for the knob, and assemble!	IMG_1563.jpg
... However, one side's disc was machined too thin, which means the gap between discs was too big, and the thing doesn't grip due to twisting, so...	by too thin, I mean the rod sat too far above surface
16+1. I need a spacer/washer. Went looking for copper, which I thought would be grippier, but could only find some 2mm brass sheet:	IMG_1564.jpg
16+2. Make it round-ish:	IMG_1565.jpg
16+3. Use round file to make a groove in the disc where the rod sits, and assemble again:	IMG_1566.jpg

So, I now have a base, with two rods for some positioning, but I need to attach the DI.

Go searching again, and find one old Mitutoyo swivel clamp.
One hole grabs the 8.5mm rod OK, but the other won't grab the 8mm end of my Mitu'o DI???


Some quick boring of a little aluminium tube, and viola.

Here it is, across the rear Vs of my Hercus, showing chuck's 0.15mm run out:
IMG_1567.jpg

Originally Posted by nigelpearson

The toolmaker took back his Mercer mag-base, that looked a bit like this:

s-l1600.jpg



For a while I tried to cope with a smaller/weaker base,
but after it fell off something and bent my large plunge indicator, it was time to build a better setup.


I was given a fine adjustment spring rod thingy a few weeks ago,
so I just need a good mounting system. Rummaging around,
I found 50mm generic base with a broken hydraulic arm.

1. Unscrewed broken arm, its an 8mm thread. Grabbed some scrap rod, machined a ~7.9mm step on the end, and used crappy 8mm die to cut the thread
2. Screwed it into the base, then spent way too long, trying to cobble together a clamp from available junk. Decided I would machine a twin disc swivel clamp. Find some cleanish 50mm round, face in lathe:	IMG_1522.jpg
3. Drill through at 11/64, and started 1/4"WW thread: (to match my box of cheap old screw handles)	IMG_1523.jpg
4. Grab in the mill, load 10mm end mill, and machine some flats for accurate drilling: (Spring rod is 8.5mm diameter. and scrap rod ~9.5mm diameter. I sort of just eyeballed slot offsets)	IMG_1524.jpg IMG_1525.jpg
5. Spot drill: (actually a lathe centre drill, because I don't have any real spot drills, but is conveniently 10mm diameter, so no collet change required ! )	IMG_1526.jpg
6. Drill both thru at 8.5mm:	IMG_1527.jpg
7. Enlarge one to 9.5mm: Made some colourful swarf !	IMG_1528.jpg IMG_1529.jpg
8. Back into the lathe for parting off. First, rotate/align parting tool to the job: (which is hard against the chuck face)	IMG_1530.jpg
9. Then, use side of tool for aligning job in chuck: (my chuck is bad, and this saves me dial indicatoring)	IMG_1531.jpg
10. Part off between discs. This didn't go well. There wasn't quite enough space between the holes, so it was an interrupted cut, which killed my insert. Finished off with hacksaw:	IMG_1540.jpg IMG_1549.jpg
11. Face off, and check the rod still fits: (I was worried the lathe might have pushed the material in at the edges)	IMG_1550.jpg
12. Load the other disc in the chuck: Using two parallel-ish rods as spacers	IMG_1551.jpg
13. Face this one off: On this one, I barely cut into the hole	IMG_1558.jpg
14. De-burrrr: (and then I filed the edges also)	IMG_1560.jpg
15. Finish up the thread. Mag base and rod comes in handy:	IMG_1562.jpg
16. Drill other disc thru at 1/4", find a washer for the knob, and assemble!	IMG_1563.jpg
... However, one side's disc was machined too thin, which means the gap between discs was too big, and the thing doesn't grip due to twisting, so...	by too thin, I mean the rod sat too far above surface
16+1. I need a spacer/washer. Went looking for copper, which I thought would be grippier, but could only find some 2mm brass sheet:	IMG_1564.jpg
16+2. Make it round-ish:	IMG_1565.jpg
16+3. Use round file to make a groove in the disc where the rod sits, and assemble again:	IMG_1566.jpg

So, I now have a base, with two rods for some positioning, but I need to attach the DI.

Go searching again, and find one old Mitutoyo swivel clamp.
One hole grabs the 8.5mm rod OK, but the other won't grab the 8mm end of my Mitu'o DI???


Some quick boring of a little aluminium tube, and viola.

Here it is, across the rear Vs of my Hercus, showing chuck's 0.15mm run out:
IMG_1567.jpg

Hi Nigel,

Did you ever see the thread that I did on my dial indicator for the lathe ? I use mine for all sorts of setting up including stuff in the four jaw.

14-04-2020-001.jpg

I simply grip it in the tool post, set at centre height of course. The aluminium strip is bent so that it doesn't quite push on the dial gauge plunger when relaxed. I have another without the aluminium strip for use when working further away from the chuck jaws.

HTH

Originally Posted by BaronJ

Hi Nigel,

Did you ever see the thread that I did on my dial indicator for the lathe ?

Yes (and thanks for the reminder).


1) I love the "lever" aspect of that one, that takes the DI away from the chuck.

If I ever setup for milling QCT holders,
I will make a quick change version of that.
Sort of like this, but with your lever/pivot idea:

SAM_0787.jpg



2) I think your holder gets clamped in like a boring bar?

Which is good to keep out of the way if you are tapping down to centre something,
but means you have to keep turning the chuck back 90° to drift/hammer down?

My ideal would be something that levered underneath the job.
Both away from the drift, and still in the vertical axis without turning the chuck!





...but for now, I have a DI stand that shouldn't fall over too much,
and can reach the chuck from the rear Vs of the Hercus.

(hope it doesn't magnetise the bed )

Hi Nigel, Guys,

I find that clamping the gauge in the tool post very convenient ! I have an expensive "Noga" that I think only came out of its box once when I got it, since then its been sat in a cupboard unused.