Thread: Swivel Base Revisited

Hi BT,
Smooth isnt flat.(have you checked out how much concave yor lathe cuts, if any?)
You need to put it on a flywheel grinder.


Not so sure about the graduating being illegible, others might be able to help there. Might look great.

Stuart

Stu,

I wasn't suggesting smooth was flat. Smooth as opposed to rough. I'll blue up the little surface plate tomorrow and see how things look. Sadly there is no flywheel grinder in the garden shed.

Ew,

What's visible is everything not covered by the 130 x 80 tee slotted upper section. In other words, a fair bit. Let me do some checking with the granite plate tomorrow . This is becoming a xxxx of a job.


BT

Originally Posted by Stustoys

Not so sure about the graduating being illegible, others might be able to help there. Might look great.

I scraped the top of my cross slide, where the compound mounts, and the numbers are harder to read now. The scraping scatters the light. It had to be done and I'm getting used to it. I don't know how you could remove the scrape marks without sacrificing the flatness, except with a surface grinder. Maybe a lap - a proper one like Phil's?

Originally Posted by Anorak Bob

I cleaned up the edges of the tee slot on the mill this afternoon then set the base up again on the faceplate. The plug is a reasonable fit, the finish on the cast iron isn't. Cast bar, in my experience, varies in hardness. The final cut was about 0.001 deep witth the slowest feed . Maybe too slow. My fear is that if I have another go I'll expose the end of the blind M6 tapped hole in the plug. Me being anal I suppose, no one will ever see it.

What if you lower the area where the markings will go - only a couple of thou - and leave a turned finish on that, then scrape the higher mating surface true?

Originally Posted by Bryan

What if you lower the area where the markings will go - only a couple of thou - and leave a turned finish on that, then scrape the higher mating surface true?

Now that sounds like a good idea! As Bob has a square spinning on top there would be a risk of scratching the divisions as the corners pass over then.

I happen to know a guy with a flywheel machine that I might be able to talk around, but you didnt leave us much to play with.

Stuart

Boys, the problem with lowering the markings is that the intended marking location is directly above the outer land of the base's tee slot. I feel a bit like I'm painting myself into a bit of a corner with this project.

I blued up my man junior plate and gave the base a blueing. F...ing hopeless. The centre was the only part making contact. I repositioned the tool and adjusted the gib screws to accommodate some of the wear in the cross slide. Better result. I also used a fresh insert. I noticed that yesterday's facing effort didn't appear flash because the insert was worn. After the adjustments the result improved. I could not lift the baseplate off the granite, I had to slide it off sideways. I imagine that I will need to scrape the underside of the round base and probably the bottom of the top profiled section.

I have marked the intended graduation location with a blue marker. It's not like there is an expansive view if they are in that location. There is alway something waiting to bite you when you make up stuff on the hop.

BT

The method of securely mounting the tee slotted upper section on the round baseplate as suggested by Stu* has been adopted ( with naturally a couple of minor tweeks ).

I had started off badly by thinking I could accurately tap a 12 x 1 with a tap held in a tap handle in turn held in the tailstock mounted chuck. 5 thou runout ended that idea. I had a very small threading tool that I reground to 60 degrees and cut a 14 x 1 thread and counterbored the hole to a depth of 3.5mm.

My first few attempts at making a spigot for the original 12mm thread were unsuccessful. I had been using 4140 but the swarf ended up twirling around the nicely turned bar and marred the finish. I gave up on the chrome moly and used 1214 for the 14mm threaded spigot. Rather than rely on a drill bit to drill the tapping hole for the M6 screw, I used a tiny boring bar to bore the 5mm hole. I had a go with the very small threading tool shown in the photos mounted directly in a collet but there was insufficient clearance ground below the cutting edge. It would be fine in a large diameter bore but not 5mm.

All worked out well in the end. Next step is the cam locking tee bolts.

BT

Originally Posted by Anorak Bob

The method of securely mounting the tee slotted upper section on the round baseplate as suggested by Stu* has been adopted ( with naturally a couple of minor tweeks ).

I had started off badly by thinking I could accurately tap a 12 x 1 with a tap held in a tap handle in turn held in the tailstock mounted chuck. 5 thou runout ended that idea. I had a very small threading tool that I reground to 60 degrees and cut a 14 x 1 thread and counterbored the hole to a depth of 3.5mm.

My first few attempts at making a spigot for the original 12mm thread were unsuccessful. I had been using 4140 but the swarf ended up twirling around the nicely turned bar and marred the finish. I gave up on the chrome moly and used 1214 for the 14mm threaded spigot. Rather than rely on a drill bit to drill the tapping hole for the M6 screw, I used a tiny boring bar to bore the 5mm hole. I had a go with the very small threading tool shown in the photos mounted directly in a collet but there was insufficient clearance ground below the cutting edge. It would be fine in a large diameter bore but not 5mm.

All worked out well in the end. Next step is the cam locking tee bolts.

BT

Bob
Once again nice work.
I was particularly impressed with the collet held boring bar.
A very convenient tool.
regards
Bruce

Originally Posted by Abratool

Bob
Once again nice work.
I was particularly impressed with the collet held boring bar.
A very convenient tool.
regards
Bruce

Ha Ha, You're just happy that I'm using that gumby 1214 stuff Bruce. I have to admit it's beautiful to work with. Imagine holding a bit of tough stuff in the jaws of the baby Sherline chuck and expecting it to stay there.

Those W20 collet holders have worked out to be dough well spent.

BT

Hi BT,
Nice going. Is it to early to say the end is in sight?
Are you going to stay with the sine bar?

Stuart

Originally Posted by Stustoys

Hi BT,
Nice going. Is it to early to say the end is in sight?
Are you going to stay with the sine bar?

Stuart

Well Stu, apart from some careful scraping I'm tempted to leave the base in its unadorned form. Graduating with a pointed tool will raise burrs and create yet another problem. Far easier to go the soft option with the whizzo mini sine bar.

I don't imagine that the tee bolts will be real easy. Rather than struggle with 4140 from the outset, I think I'll do the trial and erroring with 1214. I'll start with the job of turning the cap screws into cams.

BT

Bob
I reckon you will get a lot of use out of that little Sine Bar.
After a lifetime of improvising with feeler gauges, adjustable parallels, telescopic gauges, planer gauges etc to set the opposite height for the Sine of the predetermined angle, I finally lashed out on a brand new low priced set of Gauge Blocks from the USA. Shars..... Sub Continent Mfg
They were $76
Now, I know these are not in the same league as Starrett, Johansen, Mitutoyo etc however since getting them Ive found them to be very handy (like all tools) & in all honesty, accurate enough.They wring together & are convenient for all sorts of jobs.
Sine Bars are also very useful tools
regards
Bruce
ps Here are a couple of photos of my 3 inch Sine Bar in use & a photo of the Gauge blocks

Bruce,
I have been looking at the blocks from ctc, no doubt out of the same factory as yours. My one concern was the ability to wring them together, it is good to know they do. To see van da waals forces at work I think is really something amazing.

thanks for more info on the Chinese gauge blocks I am also considering a set from ctc not sure whether to get imperial as I have two imperial sine bars or metric

Originally Posted by welder

thanks for more info on the Chinese gauge blocks I am also considering a set from ctc not sure whether to get imperial as I have two imperial sine bars or metric

Easy Andre, get one of each