slide fits. box/box and tube/tube

[gavuk]

Is there a chart somewhere to find what size box will slide fit into another ?also for tube ..for different wall thickness's....rather than trawling the steel stockists?...cheers Gav

 

[astro_al]

You won't get a sliding fit in ERW tube as it has a seam running down the inside. You'd need CDS (cold drawn seamless) or similar.

I've never tried to find some in earnest, but nothing I've come across has ever fitted precisely - there is normally a bit of wobble. Possibly the only way to achieve this is by machining one or the other piece.

Al.

 

[Shox Dr]

There are quite a few tubes that will "telescope" You will have to trawl through as it depends on the wall thickness of the outer tube.

Search for "tube and Pipe Group" they are called something else now but it will bring their site up. On the site go to Hydraulic tubing (CDS) there is a list of all the tubing you can get, from there you can figure what fits in what


Box section is not so easy as it is not drawn after welding so has a ridge on the inside, you can get a sort of descent fit, but it will never be spot on

 

[Pete.]

I did see on another website a guy had made a tool for shaving off the weld flashing from inside ERW box section. It supposedly worked quite well.

 

[Hitch]

We had one a place i used to work at. Quite effective. Quite easy to make aswell really.


What sort of size range are you after Gav? 20mm goes in 25x1.5wall, sometimes it will go in 25x2 wall... 26.9 fits in 33.7 x2.5, sometimes 3mm. 42.7 normally fits in 48.3x2.5
Best bet is to try some before you buy though.

 

[gavuk]

....i have a bike stand and roller support to make for my bandsaw...i've always selected by trial and error but wondered if it had been worked out or at least remembered by you guys .........we don't carry a decent steel stock where i work now and i knew i coudn't get to a stockist this w/e....Karl/pete...i'm sure i'm not the only person interested in the shaving tool,,,,,links, photos ?........cheers Gav.

 

[Hitch]

Basically a frame to hold the bit you want to cut the seam from, then a ram with a fairly long stroke, and cutter, just a bit of square tool steel i think, might have been tct...
The one they had was pneumatic iirc. A hydraulic version would be quite easy to build id imagine.
When you get to the end of the stroke, you could put a spacer rod in to cut further. The ram slid sideways to allow you to insert the spacers.

Thats from vague memories mind, think i only ever used it once about 4/5 years ago

 

[Shox Dr]

Just reread your post, and my beer induced reply.

Sorry I can't help other than what I said. That said, do look at their site, they stock a lot of sizes, and are far cheaper than any one else. I bought 60mtrs of 1.125" CDS a 3mtrs of a size that telescoped inside, from them and they were over £200 cheaper than the next quote.

 

[gavuk]

my beer induced reply./QUOTE]

......Thanks for all replies ....i will be making a note of any good slide fits that i find for future reference .......Gav......Karl will keep my eyes open for more info on the shaving/dressing mc ,,sounds interesting

 

[pidgeon chit welder]

You should be able to make a device to scrape the crud off the inside of a tube by getting some long high tensile steel studding , boring a machined block of mild steel ( machined to the tube ) , centrally along the axis thread it to the studding size , then case harden it all over especially in the threaded hole , then using the high tensile steel studding and any extending devices etc draw it through the tube using a ring spanner on a high tensile threaded nut with a thick end plate washer .. similar to the way a gunsmith draws the barrels of a hand made shot gun true and clean ( they used to use case hardened balls with large diameter studding so I'm told )


Start off the initial internal clean up using a flat file and file several inches in making a tiny leading in edge at the same time.

Don't for get to lubricate and back off the block every few inches for the initial clearances to stop getting crud bind up ( like tapping a thread..
The last clean up using the biggest block should be able to be pulled in one lubricated direction only, like a reamer ..


For long tubes over 1.5 mtr could you use a heavy motorcycle chain as the draw rod and then make a simple chain pulling device over a shrouded cog etc? Or even an old scrapped chain leg off a steel sling.

You may need two or more draw blocks if the tube is really bad before you can get to the correct size..

If you cannot get a close enough fit ,could you use a solid steel bar for the inner ?

 

[gavuk]

hi "PCW"......to be honest the question was very general,not aimed at any specitic job although i was planning a bicycle repair frame ,i was intending to use 25x50 box,i ended up making out of stock i had laying about and fabbing up a slide ,i hoped someone had a chart or table for future reference....many thanks Gav

 

[English Steve]

We use box/box sliding fits quite often, but they really are a PITA. The tolerances on box are so wide that you never get two fits the same - even from the same bar.
For some applications, we have started fabricating the outer box so that we have some control.

 

[Weldingartisan]

I've just finished a job using 30mm x 2mm wall SHS and found 1" x (14swg) is a nice sliding fit. W/A