PDA

View Full Version : Honing a bore



HWooldridge
11-26-2015, 10:26 AM
A buddy of mine is building a few small pumps using 3/4" black pipe. He asked me to figure out a way to hone the inside to a consistent bore size over about 20". He doesn't care so much what the ID comes to because the leather washers can be cut to any size - but he wants a fairly consistent diameter throughout and a medium finish - maybe 120 to 180 grit or so. First thing that popped into my head was a Sunnen mandrel and stones but I'd still have to build some way to drive in the lathe. Has anyone seen or built a good homemade tooling remedy to hone (or bore) a few thousandths and keep a fairly consistent ID size?

Thanks in advance. Hollis W

gvasale
11-26-2015, 10:35 AM
Black iron pipe has a weld line that may be tough to work around. The weld seam is pretty noticeable. DOM tubing would be a better choice, or round bar stock drilled (gundrilled) might be cheaper than DOM tubing. Just my opinion.

wierdscience
11-26-2015, 10:54 AM
Black iron ERW pipe is the last thing I would use to make a pump cylinder out of,that weld seam is nasty.
If he insists,I would make up a long shank reamer big enough that it will clean the weld seam out and wipe a few thou off the walls,then follow up by honing with a ball hone for a few days until it smooths out enough to make a seal.

DOM tube is not THAT expensive-
http://www.mcmaster.com/#7767t371/=zz97mg

HWooldridge
11-26-2015, 11:15 AM
I might be able to convince him to use DOM tube but he may still want a hone job to make sure the bore is close to the same size over the entire length. Not sure what the tolerances are as supplied.

Rustybolt
11-26-2015, 11:24 AM
I might be able to convince him to use DOM tube but he may still want a hone job to make sure the bore is close to the same size over the entire length. Not sure what the tolerances are as supplied.

DOM is pretty consistent over its length. if he's using leather seals it will probably work as is.

Forrest Addy
11-26-2015, 11:45 AM
I might be able to convince him to use DOM tube but he may still want a hone job to make sure the bore is close to the same size over the entire length. Not sure what the tolerances are as supplied.

I wouldn't think of using black pipe as material for a piston pump barrel. Black pipe is intended as a conduit for non-corrosive fluids. Its virtues are few: it's cheap, welds readily by all processes, and being soft and ductile bends and forms. It's a poor selection for structural strength and being soft and gummy has poor machining properties. It's subject to abrasion, corrosion, and mechanical deformation. Black pipe is great for plumbing natural gas but as a pump barrel probably the worst material selection possible.

The bore of DOM tubing runs round and smooth well within accommodation of pump leathers. On-line Metals and Speedy Metals and other on line steel suppliers have DOM tubing in a wide variety of sizes and wall thicknesses and for a short length is not expensive.

Material selection is like picking a wife: what's cheap, easy, and available is seldom a wise choice.

johnd
11-26-2015, 12:18 PM
The seam would likely break stones and tear up a Sunnen mandrel. If you do get something seamless you could check with a good Automotive machine shop. If they have some of the long Sunnen mandrels for fitting king pins, in your size range, it would be a 5 minute job, just like dressing the stones with a truing sleeve. 20" is too long so it would have to be done by flipping end for end every couple strokes, which is just good honing practice anyhow.
If you mount a Sunnen mandrel in a lathe you would need to duplicate The Sunnen mechanism for controlling stone pressure and feed, plus a way to flood mandrel with honing oil. The Sunnen foot clutch also gives a feel and control to the process that would seem hard to do with a lathe. Why spend all the time to reinvent the wheel if what you really want is a cart?

camdigger
11-29-2015, 02:46 PM
The seam in ERW pipe is nasty enough that I would hesitate to use a hone without another operation to remove the weld flash first. On a larger pipe, I would suggest a boring operation. For 3/4", I'd look for the right size of twist drill. The seam is a large enough PITA that I'd likely grind enough off the ID for a starter guide for the twist drill.

I'd reconsider the material choice. There are other options of little more cost like assorted tubings.

JoeLee
11-29-2015, 03:21 PM
Black iron pipe isn't even round, not to mention what every one has said about the seam.
DOM is OK, but they do make ready to use hydraulic cylinder tube in various sizes. Perfectly round and polished on the ID if you can work with the available sizes.

Here is a good place to start looking http://www.teamtubellc.com/en/products/round-tubing-products/fluid-power-products/honed-tubing.aspx

JL...............

CalM
11-29-2015, 03:49 PM
A split lap made from soft material brass/ aluminum/lead/plastic/wood/fiber (even steel works!) is a very practical method to refine a bore. The abrasives can be changed to obtain aggressive stock removal or the finest mirror finish.

I would not just shove a charged brass plug into a piece of water pipe, but once the weld seem is knocked down, rapid progress can be made. A single tool last a long time.

To start from rough sawn black pipe, make up a single tipped "gun drill" that guides on the bore after it is cleaned up. That may require boring a leade on one end of each length to facilitate starting the tool.

Both tools can be driven with a hand held 1/2 inch slow speed drill motor

RichR
11-29-2015, 03:56 PM
A buddy of mine is building a few small pumps using 3/4" black pipe. He asked me to figure out a way to hone the inside to a consistent bore size over about 20". He doesn't care so much what the ID comes to because the leather washers can be cut to any size - but he wants a fairly consistent diameter throughout and a medium finish - maybe 120 to 180 grit or so. ...

Any reason a piece of copper pipe won't work for this? I can't imagine the ID changing over 20 inches, and the inside is already
smooth. Your buddy is sealing with leather washers and you're talking about boring and honing?

Mcgyver
11-29-2015, 04:02 PM
3/4" bore, accurate diameter for 20"? Some friend.

I like Rich's idea, copper pipe. Next would one of the sunnen hones, do they make the portable ones that small? Next would lapping. I've done a lot of lapping this, and have a couple of threads with pics of them. You can near perfect bores, but its a very slow process that I think would be brutal if not starting with a fairly round bore. Brutal in the sense of constant jaming up at high spots etc

duckman
11-29-2015, 06:04 PM
To bad he's not closer I have access to some SS tube 1" OD .083 wall, yeah it's a little bigger but it'll not rust.

10KPete
11-29-2015, 06:59 PM
Any reason a piece of copper pipe won't work for this? I can't imagine the ID changing over 20 inches, and the inside is already
smooth. Your buddy is sealing with leather washers and you're talking about boring and honing?

I agree, copper pipe is the way to go. No boring or honing needed. I've made a hand well pump and a couple of
bilge pumps with copper pipe and rubber or leather cups. Worked perfectly. Your buddy is making way too much
work out of this trying to use steel pipe!!

Pete

PStechPaul
11-29-2015, 08:05 PM
Sometimes I swap the first letter or syllable of a word pair to get something funny. Like "downloading updates" becomes "uploading downdates", and "smart feller". The title of this thread becomes something quite different! :rolleyes: ;)

Mcgyver
11-29-2015, 08:15 PM
:) too bad we don't have "likes" here

boslab
11-29-2015, 09:37 PM
Don't know if it's any use to you but I saw a lift pump made from black tube, about 1 or so, it had a plastic liner slid in, thick walled stuff, not had much to do with pumps so I don't even know a good one if it bit me
Mark

Rosco-P
11-30-2015, 07:04 AM
Black iron pipe isn't even round, not to mention what every one has said about the seam.

JL...............

A length of black iron pipe isn't straight either.

michigan doug
11-30-2015, 12:26 PM
As noted, DOM or rigid copper pipe would be 10x to 100x better than black iron pipe/water pipe.

water pipe is not round, straight, concentric, and machines lousy. But it rusts easily...

HWooldridge
11-30-2015, 10:52 PM
Sometimes I swap the first letter or syllable of a word pair to get something funny. Like "downloading updates" becomes "uploading downdates", and "smart feller". The title of this thread becomes something quite different! :rolleyes: ;)

Now that right there is funny, I don't care who you are...:cool:

HWooldridge
11-30-2015, 10:59 PM
This guy is trying to make some type of replica pumps that have something to do with antique tractors - the real old steam stuff. He suggested black pipe because that's the first thing that crossed his mind (and he has a plumbing background).

So the various responses bring up some interesting points - let's say he had some original pump bodies that were pitted from age...what would be the best way to restore them? Sounds like we might want to try an expanding reamer and hone/polish after the pits are cleaned up.

achtanelion
11-30-2015, 11:49 PM
Sometimes I swap the first letter or syllable of a word pair to get something funny. Like "downloading updates" becomes "uploading downdates", and "smart feller". The title of this thread becomes something quite different! :rolleyes: ;)

That's called a spoonerism, and I do that all the time. Much like puns, they seem most often amusing to the perpetrator. ;-)