brandenjs

In the automotive industry we call these a dingleberry or flex hone. We use these on new bike seat tubes at the bike shop to remove burrs that are left during manufacturing. They work very well and come in multiple sizes.

Chrome Molly

I use a 10ga brass brush for rust and gunk inside a seat tube, works pretty well. Since the fun factor of shooting my 10ga went away long ago, the brush is at least good for something now.

If you need something to actually hone the tube down, that's different. I proceed very carefully with a fine round file for the high spots that mark up the post.

Pars 

Sorry for the thread resurrection.

On my brother's Pinarello Catena Lusso, the seatpost was very difficult to get out. Bike is Columbus Cromor, and seatpost appears to be correct for that tubing (27.0mm). I bought one of the hones at Harbor Freight and was going to hone it a bit as even greased, the seatpost is still hard to insert.

Any thoughts, warnings? Bike is down to bare frame right now (frame savered it for him), so no problems cleaning anything, etc. Also, the seat binder bolt slot is parallel. I opened it up a bit, but still problems.

SJX426 

Sounds like you addressed my first thought, the pinch area of the seat cluster. If you perceive that the resistance is below the seat cluster, they a hone might be my next step after I checked that the post is really round and not oval.

Did you try a different post the same size?

Are you absolutely sure the issue is with the tube and not the lug?

Pars 

The resistance does seem to be below the seat cluster. I can get the post started the first inch fairly easily, but then it starts to bind. As for checking roundness, could I just take my digital calipers and run them around to see what sort of variance is detected?

As for your other questions:
1) No. Don't have any others in 27.0
2) Not sure. Looking down the bore, I don't see any issues...

randyjawa 

I would not waste a cent on the fancy store bought reamers or tools. The dowel idea and some emery cloth will do the trick just fine, in my opinion. To that add this...

Frame Cavity Preparation. That article will help anyone understand how to prepare a seat post cavity for its next use. Again, my opinion.

ramzilla

[QUOTE=orangeology;16411152]little bit of both. just wanted see what ideas are out there on the method side while wanted to see if there's a magic formular in terms of degunking the stubborn stuffs on the inner surface.

so far, it's great learning same time quite entertaining.
always loving to see various ideas well seasoned.[/QUOTE

I see this is a pretty old post but, thought you still may be interested in my technique. I tear down & clean old vintage Japanese bikes. After stripping down entire frame & removing bottom bracket I clamp bike down over an empty kitty litter tray. I pour a little diesel fuel down seat tube. Run a wire brush around inside seat tube and bottom bracket threads. Let it all drain into tray. Clean inside entire frame this way.

Pour used diesel fuel from kitty litter tray into a clear glass jar. After the sludge settles, decant clear diesel into a clean container and, it's ready to use again. Sludge is seperated and recycled with used motor oil.

Diesel is a good inexpensive solvent and degreaser. It's vapor is not dangerous or explosive like gasoline. Won't damage paint if wiped off with soap & water. Diesel leaves a nice residue inside frame. Been using this technique for several years with good results.

Also - BE SAFE - you need some big heavy elbow length nitrile gloves, safety glasses, shop apron, fuel containers, secondary containment (kitty litter trays) rags, and a suitable location like a detached garage. (Don't do this inside the house or kitchen).

Pars 

I'll take these under advisement. The HF hone was a whopping $3.97, so not a problem

The frame is already quite clean as I had stripped it down, washed it several times (including WD40 wipedown) and frame savered it. Just need to get the seatpost in properly and go from there. I'll see if I have a brush similar to what you show Randy.

Glennfordx4

I use carb clean on a rag with a long screwdriver for grease clean up, I then use a small drum sander on a 24" drill bit extender to do the final clean up followed with air from a blow tool, works every time. Doing it this way lets me choose what grit I want to use and it smooths out the frame joints as well as the slot ( I also file a radius on the inside of the slot ) so I won't scratch a seat post when installed.

Glenn

fietsbob

Stripping the BB Out , lets you Access Both ends of the seat Tube ,, a Length of Dowel with a Slot across the end

can take a strip of Carborundum Grit cloth to spin the dowel and lower it in the tube as you go then take the strip out of the BB shell when You Get there.

there should not be paint very far down from the ends anyhow ..

Velocivixen

How about lightly sanding the seat post? Unless it's a very collectable or rare post, it would work. I had to sand a Nitto Technomic stem to 22.0 (from 22.2), for my French bike. Anyway, just another way to go about it.

arex

ScotchBrite pad on a dowel, like someone else said. Unless the tube is really foul with grease and gunk, you probably don't want to clean it completely...a little grease for rust protection hurts nothing.

Pars 

Some here need to read more completely ST was already nice and clean.

I took a few light passes with the hone, after cleaning both the seat post and the seat tube to get any of the grease that I had used out before honing.

Before honing, I painted the lower portion of the seat post with a sharpie and did some insertions to see if I could see anything out of the ordinary, per Randy Jawa's excellent site, but could not see anything conclusive. The ST looked and felt smooth, no jaggies, etc. Using my digital calipers, the 27.0mm seat post measured between 27.08 and 19.86mm when working around it, so it isn't quite perfectly round. It is an American Classics post BTW.

After honing a few passes and cleaning, the post is going in acceptably so I greased it and the ST and went with that and should be good. Thanks for all the input!