Thanks: 0
Likes: 0
Needs Pictures: 0
Picture(s) thanks: 0
Results 1 to 15 of 58
-
31st Aug 2012, 06:57 PM #1Banned
- Join Date
- Feb 2012
- Location
- Adelaide
- Age
- 73
- Posts
- 153
Completed (almost) Pendulum Level
Here’s some pictures of the completed pendulum level (almost). For the pictures, I hung the vernier scale on two 1.5 mm drill bits and glued it to the slide, the scale will be mounted using 2mm screws as soon as my 2mm tap arrives. The Pendulum is mounted to the knife edge assembly via a bronze bushing inside a steel tube welded to the top of the pendulum arm, ensuring it hangs true vertically, there is no sideways movement. The knife edge has thumb screws front and rear so I can adjust the distance between the rule and vernier scale (backing them off after adjustment). The vernier scale (in 0.05 increments) is mounted to a slide which can be zeroed via a phillips head screw and tensioning spring; again, there is no movement. Above the rule I mounted a weight as a dampener to reduce swing and ensure the pendulum comes to rest in the same place each time. Every part of the assembly has been cut and re-welded so many times the finish is a bit rough now and quite a bit shorter than it was to start with, but it does the job. To test, I mounted the assembly just in front of the chuck and zeroed the vernier scale. I then moved the assembly to the tailstock end (600mm) and took a reading,. Shimming the front of the tailstock end leg using a 0.05 feeler gauge brought the vernier to the seventh increment (0.35). I carried out this procedure several times and got the same readings each time. My mathematics: the distance between the knife edge and the tip of the vernier scale is 1320 mm and the contacts on the base of the unit have 100mm centres, giving a ratio of 13.2. I then divided 0.35 by 13.2 and got 0.0265151. I never made it to high school so I can’t spell trigonometry, let alone do it; however, the method I worked out seems logical to me. At any rate, 0.0265151 (0.1590906 over the length of the bed) seems reasonable to me and presumably I could get it closer with the right size shims. If you find fault with my math, then I'm happy for you…
Last edited by tongleh; 31st Aug 2012 at 07:07 PM. Reason: forgot pictures
-
31st Aug 2012, 07:26 PM #2Senior Member
- Join Date
- Sep 2007
- Location
- Country West Oz
- Age
- 77
- Posts
- 169
I'm impressed by your set up. Looks like it would be very accurate to me.
Have you tried turning something between centres and checked how much taper you have?Regards
Bradford
-
31st Aug 2012, 07:42 PM #3
A very nice piece of kit there, well done!
He Who Dies With the Most Tools Wins
-
31st Aug 2012, 09:50 PM #4Banned
- Join Date
- Feb 2012
- Location
- Adelaide
- Age
- 73
- Posts
- 153
Changes
Some would disagree with the accuracy bit I think; and no, I haven't tested between centres yet, it was pretty accurate before levelling anyway - another day. If I was to make another (and I still might, I've had so much enjoyment from this project), I would change the pendulum to round bar, that would allow a heavier weight and also make it easier to align the rule with the vernier scale. I'd probably also change the knife edge pivot to an underslung design.
-
31st Aug 2012, 10:17 PM #5Most Valued Member
- Join Date
- Jul 2010
- Location
- Melbourne
- Posts
- 9,088
-
1st Sep 2012, 08:47 AM #6Senior Member
- Join Date
- Jan 2004
- Location
- Bellingen
- Posts
- 278
Just another thought, and I'm not sure if this has been covered yet but you could test the resolution of this setup with shims.
Hopefully this will the resolve the math debate.
Zero your scale, unlock the cam and slide a fine shim under one side and check to see how much the pointer moved. I guess your after maximum swing for the finest shim you have.
-
1st Sep 2012, 11:36 AM #7Banned
- Join Date
- Feb 2012
- Location
- Adelaide
- Age
- 73
- Posts
- 153
Excellent Idea
Excellent idea, I'll reglue the vernier and try that. On the other question of turning between centres: I think that would just show the tailstock is out, after all the carriage sits on the same plain (lathe bed) as the tailstock, I think you would have to turn something unsupported on the tailstock end to get a true reading. Anyone?
-
1st Sep 2012, 12:00 PM #8Banned
- Join Date
- Feb 2012
- Location
- Adelaide
- Age
- 73
- Posts
- 153
Stuart
For Stuart. All I stated was that I wasn’t that good at mathematics (forget about trigonometry) and as I said: ‘I may be wrong’! I also described how I came by my figures; and, I still think it a perfectly logical method. I will try Ben Dono’s idea, as soon as I have mounted the scale properly. As for ‘I’m happy for you’, well that may have been out of line, life’s a bitch. ain‘t it?
-
1st Sep 2012, 12:24 PM #9
Threads have clearly been crossed here and it is rather confusing for those of us that havnt been following the other thread. The maths made my head hurt a bit too, but bens solution will solve the question.
Yes you need to turn a piece unsupported, maybe 4" long. Personally I would have bought a level......yes I know, I'm normally a why buy when you can make it guy, but not for measuring gear.1915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.
-
1st Sep 2012, 12:46 PM #10Banned
- Join Date
- Feb 2012
- Location
- Adelaide
- Age
- 73
- Posts
- 153
Why make when you can buy
Well, you can buy knurling scissors, die holders, coolant systems and just about every other item we use on a lathe or mill, but most of us have made these items or other items of a similar nature at one time. For me, it's the challenge and of course I enjoy projects of this nature, keeps me out of the pub.
-
1st Sep 2012, 12:51 PM #11
I suggest you re-read my post......i did not say why make when you could buy.
1915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.
-
1st Sep 2012, 01:10 PM #12Senior Member
- Join Date
- Jan 2004
- Location
- Bellingen
- Posts
- 278
I'm always making things that I could have or should have bought. I think we all like the idea of the challenge and lessons we learnt with each project.
I always get a kick out of finding another way. How often are we stuck on something and have to think out side the box to solve the problem.
This project really ticks that box.
The other side of it is we may have eneded up proving why this is not the best path to follow. Still a lot would have been learnt.
I just read over all that and realized I'm spouting the obvious. Sorry guys..
On a side note.. A lot of my projects end up being a new tool or jig etc to make my life in the workshop easier.. Hahaha I feel like I'm chasing my tail sometimes.. I buy tools to make tools to make my life easier in the workshop to make more tools!
-
1st Sep 2012, 01:16 PM #13Member: Blue and white apron brigade
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 7,183
-
1st Sep 2012, 01:20 PM #14Senior Member
- Join Date
- Jan 2004
- Location
- Bellingen
- Posts
- 278
Bob thats awsome! I have not had the pleasure of that yet. I read a lot of gingery's books on machine building. That system played a big part of his construction methods?
-
1st Sep 2012, 01:27 PM #15Member: Blue and white apron brigade
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 7,183
A couple of other cases where this has happened is my wood work bench.
I built the basic frame and then immediately added the front vice and then used that to make the rest of .
The same happened with my Welding Metal work bench and the welding fume hood.
My favourites are the 2 and 3 mm wide woodworking chisels I made a couple of years back where I prepared blades by grinding bevels on 2 and 3 mm wide pieces of HSS and then sharpened these. Then I turned some handles and used the blades to cut their own handle holes. It worked really well. Now I use these chisels to make handle holes for all sorts of other chisels.
Similar Threads
-
Pendulum Level
By tongleh in forum METALWORK GENERALReplies: 29Last Post: 31st Aug 2012, 09:42 PM