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pntrbl
10-20-2009, 11:30 PM
I've been able to do 2.25"x 8tpi internal threads before on my 11" Logan for cast iron backplates, but man, they were a bear. You guys eventually got me thru it, but now I'm wanting some internal 1"x8 tpi which I'm thinking is even harder. The 1" boring bar that got me thru before ain't gonna fit for one thing. So I thought of a way to cheat.

Since 1"x8 tpi is a standard thread I got a me plain old zinc nut and turned it down to fit into a pocket in the part I want the threads in. Here's a pic of both parts.

http://i115.photobucket.com/albums/n300/pntrbl/SpindleStop001.jpg

And here's a pic of them together.

http://i115.photobucket.com/albums/n300/pntrbl/SpindleStop002.jpg

I'm thinking silver solder would be a nice clean way to attach them, but since I've never done that before how would I know? :rolleyes:

The bigger part is 1018, 2.125" in dia, and the threads are whatever they make standard zinc plated nuts out of.

I have a OA torch. Propane is also an option. I could very easily be persuaded into buying a hot plate if that would work. Experience wise I've soldered copper pipe and electrical stuff. Soldered lugs on a long set of battery cables once with the OA.

Any advice on silver solder methods and materials, or alternative attachment methods is welcome. There's a distinct possibilty this is another one of my crackpot ideas, and, if that's the case, I'd appreciate knowing that! :)

Thanx for any help.

SP

Highpower
10-20-2009, 11:43 PM
Personally, I would smear some Loctite 609 retaining compound on it and call it a day. :D

http://www.henkelna.com/cps/rde/xchg/henkel_us/hs.xsl/product-search-1554.htm?iname=Loctite%C2%AE+609%E2%84%A2+Retainin g+Compound&countryCode=us&BU=industrial&parentredDotUID=productfinder&redDotUID=0000000HWO

TGTool
10-21-2009, 12:35 AM
I've done a similar operation, but sweating a sleeve on a larger diameter that I'd ruined by turning undersize. My first try with brazing compound didn't work well because the stuff didn't wick into the crack well and I couldn't get the whole thing up to heat at the same time.

I got some silver solder with a high flow rating and it worked great. Fed in at the top it just showed as a bright line at the mating surface at the bottom. I think you can get your job done just fine.

snowman
10-21-2009, 12:37 AM
Use the right flux and the right solder and it's a piece of cake. My biggest problem is that I always overheat the workpiece.

Bill Pace
10-21-2009, 01:25 AM
My biggest problem is that I always overheat the workpiece.

Aint it the truth!! I can braze, oxy-weld, wire weld, stick weld, etc etc but I cannot get silver soldering down -- for this very same reason ... too much heat!!!:mad:

dp
10-21-2009, 01:40 AM
I wonder if one of all'a y'all could clear up the silver solder mystery for me. I've used silver solder in electronics but I've come to understand that is not the same thing as what is used in machinery circles, that being I've known as brazing with brass and flux. Some of the confusion may come from reading descriptions from foreign countries regarding the process.

So is silver solder in this application at all like brazing or is it more like soldering copper pipe? If you don't ask the stupid questions you stay stupid! :)

pntrbl
10-21-2009, 01:44 AM
Well I've been messin' around with whatever I had on hand. I know it's "some" kind of silver solder and I'm using the flux I had leftover from copper piping my air lines, but so far ... it ain't working!

It seems like the flux is all burnt and gone before the solder ever melts. I started with the propane but it didn't seem to have enough capacity to get the whole part hot. Then I went to the OA but I think it was already too late.

Just to experiment I cleaned up some scrap and had a fresh shot with the OA, but I think l'm violating the right flux right solder law Snowman mentioned.

Loctite 609's looking better and better .... lol.

SP

darryl
10-21-2009, 02:02 AM
In electronics, what they call silver solder is silver bearing solder. It's stronger than regular solder and takes a bit more heat to do, but it's still soldering.

Silver soldering is brazing basically, and takes much more heat to do. It's also a lot stronger. There are many alloys available- one that I use, because it's available locally, is called easy flo 45.

One thing I found to make it easier to silver solder is to heat both parts till they discolor, etc, then let cool. Clean both up well, then re-heat for the silver soldering operation.

It helps to have a gap for the solder to wick into, so when you machine the parts, make it about a 3 thou loose fit. Then put punch marks around the inner part, the nut in your case, such that the dimples you raise make the parts a tight fit again. Now you've got some room for the solder to flow into.

I would wipe some flux on both mating surfaces before pressing the pieces together, to ensure that there is flux within the spaces. When you heat, the flux will already be preventing oxidation in the gap and the soldering should go well. One more thing- it helps to chamfer the edge of the hole and the nut, so when they are pressed together you have a bit of a vee where you would apply silver solder. Think of it as the gap between the parts being a bit bell-mouthed- this is a 'wick starter'.

And yes, you do need the right flux.

Paul Alciatore
10-21-2009, 02:13 AM
You are going to a lot of trouble to avoid threading a hole. It's true a 1" boring bar won't fit, but you don't need a 1" bar for a hole that is only 1 - 1.5 inches deep. Look at this:

http://www.wttool.com/product-exec/product_id/37871

3/8" diameter and three inches long: it's plenty long enough and narrow enough for the job. And it only costs a few dollars. Grind one end of the tool bit to bore the hole and the other for the threading. Start off by drilling to 5/8" or 11/16" or 3/4" or so and just bore the rest. Then thread. A lot easier than all that soldering and the thread will be a lot more concentric.

barts
10-21-2009, 02:21 AM
True silver-solder is very fluid once molten, and will wick into .002" gaps very nicely; it has little strength when filling large gaps. Cleanliness is very important; I find a dilute hydrochloric acid pickle very useful in getting solder to wet steel surfaces. When I silver-soldered the 110 copper-steel joints in my steam launch boiler, I found that, after a thorough brushing, heating the steel nipples to 300F or so (guesstimated) and then cleaning the joint surfaces w/ an acid brush and hydrochloric acid (stay clear of the fumes) prior to fluxing made getting leak free joints pretty straightforward; I had one joint leak afterward and it was readily repaired.

I'd use a brazing flux containing fluorides even though they're toxic - they seem to work best. If you use cadmium-bearing solders, be careful not to overheat the solder as the resulting fumes are quite toxic.

For small parts, particularly of brass or bronze, you'll find a propane torch easier to use, and less prone to locally overheating the parts.

- Bart

dp
10-21-2009, 02:38 AM
For small parts, particularly of brass or bronze, you'll find a propane torch easier to use, and less prone to locally overheating the parts.

And now we're at the reason for my question. I was trying to braze a part a few days ago using MAPP gas. The rod was fluxed brass and of course it would not melt. I got out the O/A torch and made short work of it. My guess is (can you tell I'm no expert, here) that fluxed brass won't work with lo-heat gases. I've soldered miles of copper pipe (and never had a problem with Chinese toxic drywall :) ) but have never had luck using propane or MAPP with brass rod. Is that normal?

And apologies for hijacking the thread - it might be a good one to start fresh.

Astronowanabe
10-21-2009, 02:59 AM
Mapp and Oxygen are perfect for brazing brass or silver solder, harder to overheat the joint. use a borax flux. I do not think straight Mapp will work with anything but the lowest temp silver solders

pntrbl
10-21-2009, 03:02 AM
And apologies for hijacking the thread - it might be a good one to start fresh.

No apolgy necessary dp. All good info to me.

I just did a google on hydrchloric acid, wondering where I might get some, and I see it is known historically as muriatic acid. I already got some of that! Thankfully one bottle still has a label and I see it's 29% hydrochloric acid. Somewhere in that google mess I saw 18% was good for a pickle, 50% more water should do that, but for how long?

barts?

That and I need to get some kind of known silver solder and the flux that's designed to work with it.

SP

dp
10-21-2009, 03:09 AM
Mapp and Oxygen are perfect for brazing brass or silver solder, harder to overheat the joint. use a borax flux. I do not think straight Mapp will work with anything but the lowest temp silver solders

There's the problem - my MAPP gas was burning the same air I was breathing. Hot, but not hot enough.

pntrbl
10-21-2009, 03:17 AM
Paul A., I know you're right in that a 1"x8 tpi thread shouldn't be a big deal, and I've got a 3/8" boring bar among numerous others, but internal 8 tpi without giant amounts of chatter out of me and my Logan is an enormous amount of trouble. My 1st backplate took weeks and about 4 times more metal than was necessary. The major thread on the subject was titled "Still No 8tpi" and it ran for 4-5 pages until the good members here on the board finally got me thru it.

I have since used those lessons to make another for a sweet little 8" 4-jaw I got from BadDog, but it wasn't exactly easy. Believe me, a 3/8" bar in a smaller hole trying to cut those big ol' 1/8 wide threads is not going to be pretty ....

SP

Astronowanabe
10-21-2009, 03:41 AM
a 3/4" boring bar should be good to start and possibly a 7/8 if chips are not a problem.
I wonder though with through holes like this, especially if they are much deeper, if a cross between line boring and a boring head would work.

the setup would be boring bar in the chuck, other end end supported in tailstock with a live center the threading bit in the middle of the boring bar is feed by a set screw pushing on its back, bit clamped with another setscrew if need be ...
and the work piece is riding on the carriage. after each pass and return you would extend the bit a little further, over kill but hey!

I have a slightly smaller Logan and I think I would use just use the biggest shortest boring bar I could and maybe drive the spindle by hand if need be.

barts
10-21-2009, 04:31 AM
No apolgy necessary dp. All good info to me.

I just did a google on hydrchloric acid, wondering where I might get some, and I see it is known historically as muriatic acid. I already got some of that! Thankfully one bottle still has a label and I see it's 29% hydrochloric acid. Somewhere in that google mess I saw 18% was good for a pickle, 50% more water should do that, but for how long?

barts?

That and I need to get some kind of known silver solder and the flux that's designed to work with it.

SP

I usually give it 10 minutes or so... the warming it up and brushing on the acid is great if you're impatient. Degrease first, of course; I find degreaser, thorough water rinse and following w/ pickle works well. I handle parts w/ tools/rubber gloves after degreasing to keep from getting any oil on parts....

You need enough flux on the part so that the air doesn't reach the joint after it's heated.

The cadmium bearing solders are a bit easier to use, but do be careful if you use them - read the warnings, etc.

- Bart

snowman
10-21-2009, 08:43 AM
There is also some misunderstanding as to what makes silver solder.

There is both soft and hard solder. Hard solder is your safety silv or staysilv or whatever. This is brazing.

Soft solder, which is soldering, is usually 95/5 for steel I believe. That is 95% tin 5% silver. Melting temp is still higher than plumbers solder, but it will provide a strong joint.

Lew Hartswick
10-21-2009, 11:18 AM
but internal 8 tpi without giant amounts of chatter out of me and my Logan is an enormous amount of trouble.


Tell me about. I just did a 1.5 x 6 in steel . :-)
...lew...

cuslog
10-21-2009, 11:54 AM
I did some silver soldering awhile back and came across a couple interesting things (I'm certainly no expert).
My local auto parts store had it in several grades that varied from about 5% silver to about 45% silver (with the corresponding price increases). I presume the higher silver content is stronger ?
I see there's both white and black flux available, some pro's seem to prefer the black.
I read in a post a few days ago on PM that the white flux is just a Borax and water paste.

barts
10-21-2009, 01:11 PM
I did some silver soldering awhile back and came across a couple interesting things (I'm certainly no expert).
My local auto parts store had it in several grades that varied from about 5% silver to about 45% silver (with the corresponding price increases). I presume the higher silver content is stronger ?
I see there's both white and black flux available, some pro's seem to prefer the black.
I read in a post a few days ago on PM that the white flux is just a Borax and water paste.

The high silver content alloys are much stronger and have a much higher
melting point, and have very different soldering characteristics as well.

One cannot determine the chemical composition of fluxes by color; there
are very many different types (http://www.handyharmancanada.com/TheBrazingBook/Section%203/Part%2011.htm#A%20flux%20for%20every%20brazing%20n eed) for different applications. In general,
one containing borates & fluorides works well for most silver soldering...

- Bart

Mcgyver
10-21-2009, 02:52 PM
its my understanding that the 5% silver ones are correctly referred to as silver bearing solders vs silver solder. Their strength is more like that of soft solders than silver soldering

Allan Waterfall
10-21-2009, 03:26 PM
If it was me, I'd snip a few bits of silver solder of the stick,flux everything up and lay the bits of silver solder in the bottom first under the boss you're inserting.
When it's warm enough the solder will melt and the boss will drop into position,you can then apply some to the top.

Allan

The Artful Bodger
10-21-2009, 04:18 PM
When silver soldering I find it best to set up the work, thoroughly cleaned, with flux and pieces of solder cut and laid along the join. Then all it needs is heating which could be done in an oven or on a hot plate but if using a flame I think it is essential to not play the flame over the flux or fluxed area which basically means heating from the other side.

Mcgyver
10-21-2009, 07:17 PM
I think it is essential to not play the flame over the flux or fluxed area .

correct if say you're using oxy acetylene. Unless the assembly is large, i almost always use propane/air which you can apply directly without harm

darryl
10-21-2009, 10:30 PM
The 'secret' with any solders I've worked with, hard or soft, is to have the parts melting the solder, not the heat of the flame. If there is enough of the right flux and the parts are clean, the solder will melt and flow. This is the best way to do it. Laying bits of solder in place before heating is good, as is heating from the 'other side'. Play the flame over both parts so they heat more or less evenly to the same temperature.

I meant to mention earlier- when heating plated parts you might want to avoid overheating and fumes. Maybe someone here knows enough to enlighten us in this regard-

jmm360
10-21-2009, 10:59 PM
I do a fair amount of silver brazing in refrigeration work, it should suit your part fine. I use Harris 56% on new joints, very pretty joints. 15% when I have to fix a leak. White flux with a clean acid brush.

Any Welding or Refrigeration Supply should have Harris' free pamphlet with good descriptions of all their products. Refrig Supply should have the products in stock.

I feel cleanliness is most important of all, clean with scotchbrite, (don't forget to clean the brazing rod too!) and I use Zep Aerosolve II, fast evaporating solvent. Clean your hands too.

O/A with a small tip and slightly carbeurizing flame. With copper and brass at least, soon as it sets (pretty quick) wipe it down with a wet rag and when cool enough clean it again to get all the flux residue off.

Good luck,
John

Al Messer
10-21-2009, 11:29 PM
One question, I know that Logans had/have the reputation of being "chatterboxes", but---if you are threading with the compound set over to 29/30 degrees, how big of a bite are you taking at a time with the threading tool? I threaded a 10 inch Steel faceplate for my 11 inch Logan with no chatter, but I only advanced the depth of cut about 1-2 thou at a time. Maybe you are taking too much off at a time.

J Tiers
10-22-2009, 12:03 AM
I've cut 8tpi for the 1.5" spindle of a 10" Logan, ON the Logan, with no particular problems I think you are over-worrying.

get a small boring bar, even a 3/8" or 1/2" will be fine, grind a cutter, and do it.

As for the silver brazing, there are all sorts of temp levels. I used, back in teh metal sculpture days, IIRC 3 or 4 temps, so that small assemblies could be attached to larger without melting the first. the last was often sil-flo, a very low temp material.

However, I NEVER used oxy-acetylene. I have used propane and once a small butane pencil torch.

I always could melt the brazing material, as long as I could get the parts hot.

I think Darryl was the one who said it, which is to get the PARTS hot and let THEM melt the brazing alloy ("solder").

If BOTH the parts are NOT hot, you are never going to get them to "solder", so don't DO that. If the parts are hot, the solder will suddenly collapse and run into the joint. it's like magic when it works right, showing you prepped, fluxed, placed solder and heated correctly.

SOLDER FOLLOWS THE HEAT. Heat AWAY from the joint, and the sun will shine and all will be well as your solder happily runs in and makes good joints.

Well, you WILL have to clean the entier joint well, and use a brazing flux..... generally that is an inorganic flux that won't poison the joint with carbon and other unsolderable junk.

Hugh
10-22-2009, 01:09 AM
If you are finding you are 'cooking the flux' by taking too long or applying too much heat, a black flux is a bit more forgiving. also apply enough so that if you are using it up in a spot there is some already active that you can drag in with your brazing rod.

There is nothing greater than when nice shorelines appear after draging silver through the joint. The bicycle frame guys are masters of this.

Hugh

tyrone shewlaces
10-22-2009, 01:23 AM
Any advice on silver solder methods and materials, or alternative attachment methods is welcome.
SP

Hey SP. Just to be different, I have an alternative attachment method you can ponder.

I had a bevel gear with a threaded ID that was stripped out which I needed to repair a few years back. The gear teeth were still in good shape and hard to duplicate, so I bored it out and inserted a newly threaded ID sleeve. I made it a light press fit. Some loc-tite wouldn't hurt.
This was not enough to keep it in place, especially with the thrust loads it was going to encounter in use, so I used an old tried-and-true method of fixing it in place:
Just drill and tap two or three holes of an appropriate size right on the seam between the two parts. Then install a set screw in those holes, maybe with some loc-tite to keep them in place. They serve pretty well as keys, and the threads keep everything from slipping apart too. For a large part with plenty of meat you could use 1/2-13 but for your part even a 4-40 might even work if the wall is thin. I'm guessing maybe a 10-24 or 1/4-20 is about right by what I see in the picture?

Just to be clear, the drilled & tapped holes would be axial to the part - i.e. start the hole in one end and drill right along the seam of the two parts until it is through to the other end, then tap it.
Is that clearer? Seems like what I'm writing is kind of confusing, but if you could make sense of it you would see that it's a really simple solution. My part has been working like a champ for several years now.

Soldering is for blacksmiths :D

pntrbl
10-22-2009, 11:25 PM
I have decided to leave the mysteries of silver solder for another day. After a quick chamfer I wacked them parts together with my mig and moved on. One void in the cleanup, which is what I was trying to avoid with the silver, but the only way those 2 parts will ever be separated now is if one of them is reduced to chips.

As far as the 8tpi, maybe it's my ineptitude, something with my Logan which is the only lathe I've ever known, or just lack of experience in general. I dunno. But based on past experience the time I spent turning that nut down and welding it was way less than I would have spent cutting them threads. Hands down.

And many Thanx to all who responded.

SP

tyrone shewlaces
10-23-2009, 12:48 AM
It seems to me that you've taken substantial time to consider several possible solutions, reduced the problem to it's basic root elements, considered your resources, filtered out the noise, then taken the shortest route toward the goal.
There's a lesson in there somewhere. Kudos!

But I have this nagging, inexplicable wish that somewhere in the middle you would have reported a need to buy a bigger hammer. Hmmm....

beanbag
10-23-2009, 02:23 AM
looks like I was too late to this thread.

But don't you have to be careful welding or heating up zinc plated objects?

I think your solution of welding is a good one. Since I am averse to welding, I would have used a carbide insert to cut the threads. It PROBABLY would have worked. The main difference being that you would have lost about 1 thread's worth at the end of the tube due to the need to create a starting groove.

pntrbl
10-23-2009, 09:37 AM
But don't you have to be careful welding or heating up zinc plated objects?


I've never had a problem, that I know of, lol, from welding the odd nut or bolt.

Years ago my brother and I cut up a dunebuggy someone had made out of galvanized water pipe for it's suspension parts. The green smoke shoulda been a clue, but we did it anyway and got a little nauseaous over it. I think it's a matter of how much.

SP

Your Old Dog
10-23-2009, 10:14 AM
I haven't read the entire thread, someone else may have said this.

After mating the two together, I'd drill a 1/8" hole where they come together and shove an 1/8" piece of rod in there to keep the nut from spinning inside your mate. If they were really tight fits, silver soldering might not even be necessary. I did something similar to this when the nut on the spline joint for the blades to my mower deck came loose and stripped out some teeth. I slid some stainless mig wire pieces in the fit , covered with large washer and put it back together. It worked great.

BTW, that's a really slick solution to the 8 tpi problem. My 9" SB is a little light for doing 8 tpi and this is a neat fix for occasional need.

DICKEYBIRD
10-23-2009, 12:51 PM
I did a similar repair recently and just left the inner threaded repair part .002" oversize, heated the outer part with a propane torch and dropped the cold inner part into the hole. Once cooled, man nor beast will get them apart.

My pappy always said "There's more'n one way to skin a cat son."