How to remove seam from inside hollow box section ideas please

[CRS51]

Hello all, I’m making a extendable vice holder like you see in the back of some plant fitters vans where they slide out,

I have some heavy section rectangular hollow box section and another piece to slide up the inside.
They are quite a close fit to the point that the internal seam of the outer section stops the internal hollow box section sliding through.

Is there a way to remove the internal ridge ?
Any ideas welcome, Chris

 

[selectedgrub]

Groove the one that slides in.

 

[Gareth J]

On a length, like that which you want to make a slider, it's really hard to work it out with tools. You could try to make a broach that'll push through and cut out the seam.

On a similar project, I got the sizes of box that fitted well without touching the seam and welded strips of the right thickness flat around the seam and onto one of the sides to take up the slack and make the sliding fit I was looking for. A lot less hassle than trying to remove metal.

 

[james butler]

good excuse to make and fit some replaceable nylon pads to go between each surface and avoid said ridge

 

[8ob]

Pressing down the centre of one side of the male box a tad works, only needs a tiny bit to avoid the ridge. Could be done with a hammer and chisel if you dont have a press.

Bob

 

[Agroshield]

What size of box section?

What length of box section?

The most appropriate method depends on the answers to those questions.

 

[Kram]

How long a length do you need to do? Sounds short would be acceptable, and you can do that with a finger belt file angle grinder attachement.

Another way that may be quicker as its a short length is to cut along the weld seam with grinder. Clamp an alu bar as a bzcking and re weld. The bar will stop the seam from protruding, but will need the amps turned up. The advantage of this is once cut it will try to spread, but put it in vice and you can adjust the size for a better sliding fit before welding.

 

[Hitch]

How long is the piece?

A grinding wheel on an extended mandrel will do it unless its particularly long.

 

[rtcosic]

My search skills are lacking at the moment, but I recall a YouTube video of a home-made broach to do exactly that, as @Gareth J describes.
I think he also added slim PTFE bearing surfaces, as @james butler describes.

 

[rtcosic]

 

[zzr1200]

I made a sliding vice mount for my van once, choose your outter box section carefully and build the outter section first.

Suggestion:-
Internal sliding box section 90mm x 90mm as long as required, outter box setion 100mm x 100mm x 3mm wall, 300 mm long.

Then position outter section with weld at the top, now plug weld inner spacing shims to the 2 vertical and lower surfaces of outter section to reduce movement/slop. Now weld a shims to the back/end top surface and the vertical sides of the inner section to reduce side/vertical movement/slop.

Sliding lock by either horizontal through pin or by locking bolt, up to you..

Grind and fettle as required.....

 

[BrokenBiker]

Long length of threaded rod, chunk of steel that's a good fit on the sides of the tube but a bit loose too and bottom, braze a bit of tool steel on and grind a cutting edge, thread the middle of the chunk of steel, use an impact gun to spin the threaded rod and pull the cutter through.

I will admit, I've only ever done this on lengths to about 350mm.

There are videos on fireballs channel I think for something similar

 

[CRS51]

What size of box section?

What length of box section?

The most appropriate method depends on the answers to those questions.

@Agroshield thanks for the reply,
dimensions are
120mm x 80mm x 8mm hollow box section 1200mm long (Outer)
10mm x 60mm x 5mm hollow box section 1500mm long (Inner)
Thanks, Chris

 

[Agroshield]

...1200mm long (Outer)

The idea above of making a tool and pulling it through using allthread would work. I think two 1m lengths with a joiner would work if you went from both ends.

It could be worth trying a piece of wood as the bulk of the tool block, maybe with a sheet of steel screwed onto the bearing surface. Keep adding more sheets each pass through (you likely won't remove the flash all in one go).

 

[Kram]

Another easy way would be to grind a small recess along the length of the inner piece. Its not going to be loaded anywhere near maximum for your stated purpose so wont affect that use.

 

[Smallfry]

Long length of threaded rod, chunk of steel that's a good fit on the sides of the tube but a bit loose too and bottom, braze a bit of tool steel on and grind a cutting edge, thread the middle of the chunk of steel, use an impact gun to spin the threaded rod and pull the cutter through.

I will admit, I've only ever done this on lengths to about 350mm.

There are videos on fireballs channel I think for something similar

What I was thinking.

To start though file out as much as possible with a finger file.

 

[Erie Fred]

I make the outer piece out of 2 pieces of angle, shim as needed, and weld it up.