Low profile boring head plans?

[RainbowsParticipant @rainbows]

[RainbowsParticipant @rainbows]

I need a boring head to make the new over arm for my horizontal mill, then after that probably to bore a bunch of other stuff too.

Apart from off the shelf heads being money and not being as satisfying as making one I do need to minimise the space taken up because the horizontal space on a horizontal mill is less than the vertical on a vertical mill. Some commercial heads seem to be longer than necessary.

While minimising the height I still want something fairly beefy to hog out a 2.5" hole without taking a year. I also later want to make a 100mm hole to take a flange mounted motor which is probably the biggest hole I need for the near future.

Has anyone got plans for a home made low profile boring head? Or pictures or even concepts that have never been put into practice. Wanted to check the hivemind before designing something myself which turns out to be already done better.

[Ady1Participant @ady1]

If you have a digital subscription there's one in 4250 you could adapt

There's been a lot over the decades, if you have a pile of old mags you can have a flip through with a reasonable chance of success

It's one of those things that's been a bit done to death over the decades

There's a magazine index here

Let me know if one catches your eye (pre-2000)

[Ian S CParticipant @iansc]

Fo the motor plate, chain drill and a half round file is probably the quickest way for a one off job.

Ian S C

[Chris Evans 6Participant @chrisevans6]

A simple boring bar with a bit of HSS held in it and tap it out to achieve your size. If you are making the bush to suit you are not looking to achieve size to a thou. I used this method until I got a boring head. You can set close to size by tapping the cutter out on to a known edge/table and use the machine dials to get to size.

[RainbowsParticipant @rainbows]

Ended up making a design, probably isn't particularly low profile but in case anyone cares I will post some pics anyways. Sadly I don't have a digital subscription either

The horizontal mill doesn't like internal dovetails, I have a 60 degree cutter but it would only be able to do the exposed dovetails. Collet chuck is still on the wishlist. So instead of dovetails we have box section ways.

The pocket for the lead screw nut is going to get hogged out with a drill press and a dremel tool.

Going to use a M8x0.5 fine thread. Lets me get 0.01mm on a 10mm dial. Probably going to push a 10mm collar on to the severed head of a m4 cap head or something like that. Not fully worked it out yet. Could have a go trying to make a hex broach.

Boring bar gets locked in place by tightening the central bolt of each gib down hard.

A bronze piece retains the leadscrew and locates it axially. Pretty much a copy of my lathe compound slide.

The bar is held by a cotter pin. I also have a plan for a horizontal holder for really big bores. Could add more attachments but I can't think of any of the top of my head.

Body is 80mm diameter. Total length 148mm. Length minus taper is 62.5mm. Takes 12mm bars.

Might still tweak it but thats the overall plan.

[Neil WyattModerator @neilwyatt]

Multiple holes in the slide will give you the same range of positions as a moveable holder, increase headroom by 20-25mm and be more rigid by reducing the number of joints.

Neil

[BazyleParticipant @bazyle]

As Neil says multiple holes in a round boss at 1/8 deltas in offset would gibe you coarse adjustment. The fine changes can be made on the tool position in the same way as for 'between centres' boring bars. You might be able to use a Devlieg microbore tool tip to adjust to tenths.

[colin hawesParticipant @colinhawes85982]

There is a picture of one I made in my album under Colin's tool designs.

[Martin KyteParticipant @martinkyte99762]

Can you not cut internal dovetails on a horizontal mill with a single angle cutter with the work set over at the dovetail angle? Just asking.

regards Martin

[RainbowsParticipant @rainbows]

Issue is that there is a 1" shaft sticking out both sides of the cutter. This would hit the top of the dovetail.

Looking at Colins I noticed I can save 16mm by sticking the nut in rather than under the moving table. (Nice milling vice too)

Will probably go as Neil says and remove the holder for rigidity. Though because I still need to be able to clamp the boring bar I am not sure if I can save much height from it.

Getting rid of the slide completely would be a wild ride. If I ever need even more space I could go for that. Have seen those little boring things in the past but never went for them. Will pick one up if the price is right.

[JasonBModerator @jasonb]

You could always use built up dovetails which won't be a problem to cut on your horz machine.

[Neil WyattModerator @neilwyatt]

Now you know you need a shaper

Neil

[RainbowsParticipant @rainbows]

If I stick it on the wishlist between the bandsaw and the surface grinder…

That said the cost of those precision angles is something in the same area as a collet chuck and dovetail cutter. Chinese prices make bodging somewhat less effective.

[Author]

Posts