Long hole drilling Help

[Alpha1]

Alpha, how about starting with a length of 6mm stainless steel barrel - it would be simple to just drill out the rifling.........

Not as simple as that I am afraid. The (OD) outside diameter of the tube is critical. In the past I have bought in stainless tube of the correct OD cut it to length then had one end of the tube welded to close it up. I then mill a slot on the welded end to a fixed length. The tube is then fitted with a Swagelok threaded fitting and inserted into a custom made holder. I don.t like this set up. All the measurement the length of the tube the size and location of the milled slot and the fitting of the Swagelok fitting have to be correct so the tube when fitted into the custom made holder the location of the insert is correct.
I want to take a piece of round bar stock of the correct OD approx 200mm long and drill a 6mm hole approx 150mm into the bar stock. Then cut a slot at 150mm of a fixed width and length. Then part off the excess and face the solid end off.
I go through about 16 of these items each year.

[shoppe]

So it is a thin wall tube your trying to make to allow the fitting of the compression fitting? I would say this is going to be very difficult to make on a lathe at the length you are wanting. Better sticking with buying in the tube.

[Pippin89]

I can afford to ruin a few to get to a suitable end result.

I would seriously suggest getting a quote to have it sparked. I would imagine you are looking at around £50 or so. By the time you have broken a few bits you might be spending that anyway.

[Alpha1]

I can afford to ruin a few to get to a suitable end result.

I would seriously suggest getting a quote to have it sparked. I would imagine you are looking at around £50 or so. By the time you have broken a few bits you might be spending that anyway.

Thanks for the input. I get were you are coming from if it was my money I would not even go there. But its not my money that I am spending.
In the mean time I have ordered a 6mm gun drill and priced up for a system for my lathe.
I have also ordered long drills in different sizes from Guhring.
WHY. Why not its all a learning curve.

[ovenpaa]

Pro Tip: Order two!

Are you going to flood the job with coolant or use a compressed air feed for chip clearance and cooling? A slow and steady feed is the only way forward and take your time to align the tool holder, oh and make sure you can get the job out without having to remove the drill as it saves a lot of time on runs.

[Alpha1]

I have only ever seen it done with flood coolant. Didn't know it can be done with compressed air. I have a compressor in my work shop. Its a fair size one. I will have to have a look at how its done with compressed air.

[Alpha1]

Actually that's not correct they used flood coolant but its pressure fed.

[Alpha1]

Thinking out loud before you invest money in tooling. Those piece of tube you were given to work with that were probably cut to length on a mechanical saw. A bit of advice pop one of them in the lathe face it off de bur it then measure the internal diameter(ID)
Could of saved a lot of money. Its a good job I am not paying for this if it was my business I would be bankrupt in no time at all.
I should probably stick to making pens at least I make some money on them.

But as I said its all a learning curve.

[ovenpaa]

Actually that's not correct they used flood coolant but its pressure fed.

Hammond should have asked you if you were using coolant or air blast

[Alpha1]

Actually that's not correct they used flood coolant but its pressure fed.

Hammond should have asked you if you were using coolant or air blast

Yes you are correct.

My understanding is Hammond do two types of drills:
Ventec drills that are designed to be used with the Ventec spray mist unit. That runs of your workshop compressed air system I would have to buy the Spray mist unit and all though I have a large compressor I am not sure if that would work. May be later on depending on how it goes. I might consider it and providing I can make a good case for my employer to fund it.

They also do speed feed drills that are designed to work with flood cooling. This is the option I am looking at. If you all ready have flood coolant and a suitable tool holder and may be a bushing to fit on your existing tool post then I am hoping that will work. We will see.

I have ordered after re measuring my example that I have here a 6.5mm by 290cm speed feed drill. I had previously ordered a 6mm but as I said in a previous post after facing of and deburring the tube I have the measurement came out at 6.5mm. So when they turn up I will have a look at getting the 6mm to work as a first pass then the 6.5mm as a second pass.

The whole thing might be a total disaster but what the heck its only money and it keeps me off the streets. And its fun I enjoy playing in the Shed and at this weird time with whats going on its good for my mental health.