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Thread: Machinists Level. Build Log.
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4th Feb 2015, 09:08 AM #1
Machinists Level. Build Log.
Hi Guys,
Following on from from some of the posts made here, including mine, discussing various alignment issues with lathes and being aware that bed twist, particularly on small lathes can be a problem, I decided to try to build myself a Machinists Level. Having seen and used a "Starret" machinists level, I thought that something along those lines could be doable.
The picture above is one I found on the net of the type of construction that I want to build. It is basically a tube containing a vial that is supported at each end on a cast iron base. The tube is adjustable at each end so that the bubble can be centred easily.
Now I don't have any cast iron suitable for this job so I propose to use brass, not just for the base, but all the parts. The vial is one extracted from a "Pound" (Dollar) store spirit level. The one I bought was 12 inches long and made from an alloy casting. It had three vials two small ones and one larger one. I used the larger one. However I also found a supplier of low cost precision vials on the internet. Unsurprisingly almost exactly the same size as the one I extracted from the store bought level.
The picture on the left is the salvaged one and the one on the right is the one I found on the net. As you can see the salvaged one only has two graduations where as the other has six, three on each side of the bubble.
Below: These are the details of a supplier and details of the vial. Both vials have the same dimensions. However the sensitivity of the salvaged one seemed to be higher. I could detect bubble movement when I shoved a 1/1000 feeler gauge under one end of the level that I bought.
www.fine-tools.com/level.htm
Vial cylindrical (Tubular Vial)
Length: 40 mm
Diameter: 9,5 mm
Sensitivity: 0.35mm/m=0.020"
Order nr. 312141 cart
Price US $ 4.80
These are the pieces of brass that I am going to use to make my machinists level. There are eight pieces in all. Only five shown here. Plus two fibre washers and the vial. The two pieces of brass in the lower half of the photograph are going to be soldered together to form a "T" section. The bottom plate has already been fly cut so that it is as flat as I can make it. The holes at the ends have been drilled and threaded M8. Then I used solder paste wiped on the bottom of the vertical piece. Aligned it on the base then put the whole lot on a hot plate to solder it together.
The brass tube is 10 mm OD and the 9.5 mm diameter vial is a good sliding fit inside. The two 1/2" diameter brass pillars are heater supports from a Hotpoint top loading washing machine, as are the fibre washers. You can see that I've turned and threaded one of them M6. I did the same to the other one.
More later:Best Regards:
Baron J.
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4th Feb 2015, 11:02 AM #2Most Valued Member
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Hi there.
Thats a lot of effort to save less than $100 on a S/H starret but that doesn't mean its not worth a try. I certainly attempted similar but I suspect like you its not necessarily about the money and more about the journey of experimentation.
Ill be interested to see how it turns out.
Good luck!
SimonGirl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.
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4th Feb 2015, 11:47 AM #3Retired
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Shop made tools
More about the journey I think, some buy some create.
My Chinese level is rated at .02mm/m, so .35mm/m may not be sensitive enough - depending on how fussy you are of course. But I do find my level a PITA being so sensitive.
Anyway the reason for my post, I saw this in GB on ebay and thought it may interest you. It doesn't give the sensitivity, but going on the number of graduations may be better suited to your task, could be worth asking a question about sensitivity.Just a thought.
http://www.ebay.com/itm/SPIRIT-LEVEL...item5b0bff8180
Anyway, I'll follow this thread with great interest. Give me a shop made tool over a bought one any day, anyone can buy a tool.
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4th Feb 2015, 12:37 PM #4Cba
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BaronJ, that vial is not sensitive enough. You have absolutely zero chance to align a lathe bed with such a plastic toy vial. You need a more sensitive vial.
But spirit levels good enough for lathe alignment have been successfully home made before. It is perfectly doable, albeit not as simple as you may have hoped for. I recall at least two articles in Model Engineer's Workshop on this subject. One is about loading (cold bending) a straight glass to achieve the desired curvature. The other article is about lapping the inside of a cylindrical glass to achieve the desired curvature, just like it's made in industry.
Have a look at this thread, post 47
http://www.woodworkforums.com/showth...ome+made+level
This thread started about a rather dubious homemade level, but there is some good discussion that you will find useful for your project.
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4th Feb 2015, 05:25 PM #5Philomath in training
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The secret to how sensitive a level is is not in the structure that surrounds it but in the vial - the more sensitive levels have the inside of the (glass) vial ground to a large radius.
While something you make may look the part on the outside, without a proper vial on the inside it won't get the sensitivity that you need for machine tool leveling.
Worse still, with a moulded plastic vial you do not have any guarantee that the surface is uniform inside. If there is a flat spot in the moulding (lack of uniform cooling for example), the vial will not be repeatably accurate.
If you want to make a level, then inquire of someone like Starrett about buying one of their precision vials, otherwise you will effectively be making a precision paperweight.
Michael
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4th Feb 2015, 08:25 PM #6Banned
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Hello Baron.
Did you notice the accuracy of the vial you linked too?
Precision +/- 1.00mm/m.
They (Stabila) claim +/- 1/32 per 72" That works out to be 0.437mm/m
Heres a vid of a bloke that was sure, his lathe was close to God truth, because no matter where he put it, it was POINT ONE. This is the $29.95 Canadian Tire version.
https://www.youtube.com/watch?v=-E7AenIOajY
You wont see an error in any machine, no matter how cheap and nasty with a level that course. Every thing will look beautiful. Zero -Zero.
Hardly suprissing if you need to shovel half a house brick under it to make it move.
I wouldn't atempt the 0.02mm/m which is the machine tool standard, for a home build.
But 0.05 or 0.1mm/m arnt that expensive from legitimate sources once you move into that $50 -$100 per vial. I'm seriously at a loss of what you were expecting at $4.80. Precision cost's. Vials are ground, not lapped
Moyer / Geier & Bluhm, do real vials at suprisingly low cost for the resolution.
http://www.wamoyer.com/products/glass/precision/
http://www.geier-bluhm.com/
I have doubt's about you seeing a change on your dollar (pound) store vial. Especially with 1 thou. What did you have the level sitting on? A cardboard box?
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4th Feb 2015, 08:34 PM #7Pink 10EE owner
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There are precision vial manufacturers in the UK.. I cannot think off them off hand but I recall seeing a UK based seller there..
Gold, the colour of choice for the discerning person.
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4th Feb 2015, 08:40 PM #8Banned
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Level Developments. They have the Wyler agency, and charge accordingly.
http://www.leveldevelopments.com/products/
Poor service, they want 3 weeks to pull anything out of stock, and megger dollars for Freight. They wont use UK-Post. Down here its quicker / cheaper to use the Yanks.
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4th Feb 2015, 09:27 PM #9Banned
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4th Feb 2015, 10:15 PM #10
Hi Guys,
Thankyou all for your helpful comments. As some have said, "it's the journey"
I do have access to a high precision level if I really needed to use one. I'm told that it has not been taken out of its case more than a dozen times in 20 years.Best Regards:
Baron J.
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4th Feb 2015, 10:29 PM #11Cba
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If its the journey you are after, you will like these articles:
this is from MEW 33, on how to grind and lap an accurate vial:
And this is from MEW 36 on how to make an accurate level by cold bending a glass tube:
And this is a link to an instruction sheet on how to grind/lap a 10 second spirit level vial for a mirror artificial horizon. No worries, it also applies to a nachinist level....
http://fer3.com/arc/m2.aspx/Making-y...an-2012-g17728
Have fun.
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4th Feb 2015, 11:00 PM #12
Build Log.
Hi Guys,
Continuing my build log for a "Machinists Level". If some of the pictures look a little fuzzy, I got a new "Nikon" camera in the vain hope that I could get better pictures than my "Fuji". It seems that the Nikon cannot focus properly for close up shots. In macro mode you have to use the zoom facility from about 12 to 18 inches. The camera is going back...
This is one of the supporting posts for the ends of the brass tube that will be used to hold the vial. As can be seen the vial slides nicely into the tube.
At this point I need something to support the tube at each end and locate it between the support posts.
I just nipped the piece in the vice for this photograph.
I have found a short length of 1/2" diameter brass bar. Fortunately it is just long enough to do what I want. I turned the ends down so that they were a push fit into the brass tube which left a section in the middle full diameter.
I next set this up at one end of the mill vice so that it was level and square I used a machinists jack to support the opposite side of the vice jaws so as not to twist the jaws when I tightened up the vice.
Using a 12 mm slot drill I then proceeded to cut a scallop in each side, so that I had a flat 4 mm thick section in the middle. I used Mk1 eyeball to cut up to the edge of the turned ends.
Turning it through 90 degrees and using the same 12 mm slot drill I rounded of both ends. I turned it over and did the other side the same. I then using the DRO drilled two 6 mm clearance holes through. At this point I realised that I haven't allowed anything for cutting the piece into two halves. I'll let you fill in the expletive...
Thanks for looking:Best Regards:
Baron J.
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4th Feb 2015, 11:08 PM #13
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5th Feb 2015, 07:29 AM #14
Would people please be mindful of copyright etc, there is a difference between posting copyright material on a public forum and sharing a bit of info privately.
We have been here before.
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5th Feb 2015, 07:54 AM #15
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