Machining marks inside a steel tube - removal help Please

Fill the slot in with a cutdown piece of tube? Solder, glue, tack it to a couple of hose clips and fit, using a piece of shaft turned to fit inside the tube whilst clamping.

Tom

How long is it? Can you bore half way and flip it around in chuck to get the other half? Check run out at far end incase your jaws are not perpendicular to spindle.

An idea and only an idea. If the ratio of length to diameter is > 5:1 can you make a boring bar with guide pads to stabilize it going down bore? Might be more trouble than it is worth but I don't know how much time, effort, and money you have in this at the moment.

Wes

I need to remove some heavy marks from a poorly finished 25mm ID tube to allow a spring driven striker to slide in it in a totally repeatable manner.

Here's a picture after I have done a good bit of work on it:

Available, drill, bench drill, lathe (no steady's), no tool post grinder and little skill.

A Flex Hone has been recommended but I've not been able to find one for sensible £ so would a 30MM OD flap wheel work.

A flexhone won't work well with a slot either. It'll wreak havoc on the abrasive balls and a 30mm flapwheel won't go down a 25mm tube until it's well worn. Ideally it's a honing job so you need to fill the slot. Aluminium or something else soft for preference but wood might do at a pinch. Saw and chisel a T shaped bit of wood to size and hold it in place with hose clips. If it sticks out a bit run a half-round bastard file over it when it's in place until it's flush and then use your 3 leg hone. Lubricate with a 4:1 mix of paraffin and oil.

Is this part of an air rifle? It looks like the spring chamber of mine which also has an abysmal internal finish but seems to work fine despite it.

it is, the air rifle is a BAM B50 a poor copy of the long out of production Daystate Huntsman and the bit of tube giving the problems is the part were the hammer slides down to the valve.

Apparently there are some other possibilities that I had not thought of and I'll explore them too.

Thanks All Ora

So you were quite near to the solution :-)

Make a cylinder of CI that fits inside the bore. Bore the round conical, make a mandrel that fits inside that conical bore. Slit the CI-part lengthwise. You got an adjustable lap, that is only missing a nut on the mandrel. After adding that, use it.

When that is too much work, here is a hack: Turn a cylinder out of some hardwood. Diameter about 0.1mm smaller than the bore. Put some lapping grit on it. Lap with it. If the diameter is too small, some drips of water will expand it.

Nick

Slit a dowell down the center and wrap a piece of wet/dry around an

through it. Use a wedge to open it as you go. Make sure you make ful strokes with it as it is running so the bore is not tapered. Us kerosene or wd-40 as a cutting fluid

-- macon

----------------------------------------------------------------------- macona's Profile:

Sorted.

I effectively cast a section to fill the slot then I was able to use my hone. It sounds a bit dramatic but it took about ten minutes to fill the slot.

I inserted a tight fitting plastic rod into tube under the slot, masked off the outside of the tube sprayed it all with a releasing agent, covered it very loosely with a thin plastic bag. Some car body filler went onto a bit of wood that was then clamped over the slot pressing the filler into it.

Next morning I took out the rod and I was ready to hone :) :)

Thanks All Ora