Hal The Van - Page 14

**WVvan** · 03-31-2010, 11:50 AM

Thanks Andrew.
The slider company also has a German branch that "Spezialist für Teleskopschienen nach Kundenwunsch". Might be useful when you get back home.

Lifting Mechanism.
Started with a piece of steel stock.

After some cutting, drilling,

And grinding,

constructed the lifting mechanism.

The bar across the top is a guide rail for testing.
Once I started testing I found I had to move the central pivot down 1/2". Also the top arm has to have the driving pivot point .8" below the bottom of the bed level.

To create the pivot connection between the different arms I've drilled a 1/4" hole in each arm.
Then used a 1/4"bolt with a nylon spacer between the arms and then a washer-nut-lock washer-nut on the end of the bolt to hold everything in place.

I originally thought I would need the nylon spacer for clearance between the two arms. After having tested it I might just replace that with a metal washer and some 3-in-1 oil to reduce friction.

Looking for suggestions: The pivot connections seem to be a bit of a kludge to me but it's the best I could come up. Can I get some suggestions on how to make a better connection so the steel arms can rotate but withstand lateral(?) force?
There is a machine shop in town but the more I can do myself the better.

Thanks,
Dave

Zaskoda · 03-31-2010, 12:23 PM

Quote:

Originally Posted by WVvan

I originally thought I would need the nylon spacer for clearance between the two arms. After having tested it I might just replace that with a metal washer and some 3-in-1 oil to reduce friction.

Looking for suggestions: The pivot connections seem to be a bit of a kludge to me but it's the best I could come up. Can I get some suggestions on how to make a better connection so the steel arms can rotate but withstand lateral(?) force?
There is a machine shop in town but the more I can do myself the better.

Thanks,
Dave

If you go the washer route, you might try some dry graphite lubricant instead of 3-in-1 oil. Being a dry lube, it doesn't gather dust and turn into gunk. You can get it as a powder in a plastic bottle or as a spray on, fast drying application.

If that doesn't work, you could try moving the nylon spacer *inside* one of the arms. I think they call it "pin and bushing". If you do this, you may have to switch to a metal spacer/bushing. Since it may create a little bit of play, you may also want to make sure the spacer/bushing is only slightly thicker than the arm itself. With this approach, you can revert to just one nut.

I think the weakest link in your design would be the distance between the two arms. I suspect that the thinner you make the spacer, the stronger the joint will be.

Ford_6L_E350 · 03-31-2010, 03:57 PM

Instead of spacer, you could use a nylon washer. And I would rather tap the 2nd arm and have the bolt screw into it and a single nut for a jamnut to keep it from loosening. If you had a bolt with 1/4" unthreaded area, it would make a better bearing surface for the arm to rotate on.

Mike

**WVvan** · 03-31-2010, 07:58 PM

Thanks for the suggestions.
After reading the comments I stopped at the hardware store to look at locking nuts and found this:

It's called a "KEP Lock Nut". Looks like it might be a little sturdier than the lock nuts with nylon at the end.
Does anyone have experience using these?

My drawer sliders arrived today. When they say "Heavy Duty", that's just what they mean.

jage · 03-31-2010, 11:43 PM

Quote:

Originally Posted by WVvan

Does anyone have experience using these?

Same as a split lock washer. The metal tabs keep a bit of pressure which keeps the nut from spinning free. I usually only use recycled ones.

There is another kind that has little dents in 3 of the 6 corners and it gets really hard to thread after the first few turns- the principle is similar to a nylon lock nut, but it's metal.

If you want to be sure add some locktite on top of using the KEP nuts.

Ford_6L_E350 · 04-01-2010, 11:08 AM

I prefer nylocs to kepnuts. If some wears and takes the pressure off the nut, a nyloc still will not turn freely, a kepnut will spin right off. That is another advantage to a threaded part and a jamnut. It does not get loose because parts wear and tension is removed.

Mike

jage · 04-01-2010, 11:59 AM

Quote:

Originally Posted by Ford_6L_E350

I prefer nylocs to kepnuts.

That's funny, I have the exact opposite preference- if you take a nyloc off and on it stops being effective. The kepnuts and lock washers have a better re-usability, and if they're flattened you can tweak them. But honestly I think any of them will work.

Ford_6L_E350 · 04-01-2010, 02:13 PM

Geez Jage,

When something is worn out you should throw it away. If a Nyloc nut turns freely it is trash, not a locknut.

Mike

**WVvan** · 04-03-2010, 10:51 AM

Thanks for all the info guys,
I had to go to Lowe's to find jam nuts but I'm going to give the ny-lock (on the store bins they are marked as "stop nuts") a try.
If they don't work I'll go for the jam nuts.

Dave

**WVvan** · 04-03-2010, 11:26 PM

Got the sofa-bed sliders finished tonight. Getting closer. In the mean time.....

A quick post on using calipers. More particular vernier calipers.
If you've been following these postings you'll have seen pictures where I'm using them.
Here's the three I own.

The top (plastic) one cost me about a buck. The middle one got for around $6. The bottom one I inherited.
I use them to measure width or depth.
I wouldn't trust the markings on the plastic one but it's good for getting a size then comparing it to a tape measure.

These are the Outside Jaws.

And for measuring inside, the Inside Jaws.

On the other end is the Depth Probe.

Once you've taken a measurement, this is how to read it.
On the Main Scale is marked inches and 1/10 of inches. Only the even numbered 1/10 marks are labeled. The top scale is the Vernier Scale. This caliper is accurate to 3 decimal places.

Here's an example measurement.
Find where the zero mark on the Vernier Scale lines up on the Main Scale. It's between 0 and 1 inch.

On the Main Scale the zero mark is pointing between 0.5 and 0.6. Between the 1/10 inch marks are three shorter marks. Each mark equals .025 inches. This value will be the same as the largest value on the Vernier Scale. Since the zero mark is to the right of the third .025 mark the measurement is
.5 + .025 + .025 + .025 = .575
before adding the Vernier Scale.

To use the Vernier Scale find which of it's marks line up exactly with any mark on the Main Scale. It will only line up with one but you have to look closely to determine which one. Add the value from the Vernier Scale, .012 in this example, to get the total measurement.
.575 + .012 = .587 inches.

Or you could use a dial caliper.

And why might you need to know measurements this accurate?
Here's one way I used them. The smaller bits had fallen out of my drill case.

The bits have been used so much you could no longer read the end markings.

Use the dial caliper to get the diameter from a drill bit then convert fraction to decimal.

Worked like a champ.