Drilling a hardened steel vice

[jack620]

I bought a new vice to mount on my recently acquired Hercus milling attachment. I intend drilling 4 holes through the vice to allow 8mm socket head screws to pass through and into 2 long t-nuts. The holes will be stepped to allow the heads of the screws to sit below the surface of the vice's base.

Today I started marking out for the holes and discovered that the vice is made from VERY hard steel. My scriber barely scratches the surface. Likewise a file. There is the added complication of the rebates along the sides of the vice potentially causing a twist drill to be pushed off line (assuming a twist drill will even do the job).

Due to the narrow width of the two 'rails' of the base, the holes will be partially in these rebates (i.e. the screws will be exposed). That doesn't bother me as long as I can drill the holes straight.

Should I consider a solid carbide drill bit or maybe a slotting mill? Or will a cobalt twist drill will do the job? I want to get this right, so I'm not keen on just jumping in and stuffing up a good vice.

Chris

[Michael G]

The toolmakers at one place I worked used common masonry bits that were sharpened up.
Given you have the whole bed length of the lathe to play with (no need to minimise height), have you considered making up a false table, wider than what you have so that you can clamp the vice using the side slots? (that is, no drilling?)

Michael

[jack620]

I hadn't considered that Michael. It's certainly an option. My only concern with that arrangement would be that it increases the overhang of the vice+workpiece from the mounting point on the cross-slide. An advantage might be that it increases the mass of the milling attachment which might reduce chatter.

[BobL]

Amongst the hardest things I drill are 5/16" holes through the centre of the hub/discs of nose sprocket bearings of stihl chainsaw bars. These hubs will take the point/edge of a standard HSS bit in seconds. To drill these I use a carbide masonry bits, slow (~160 rpm) speed, high pressure and lots of coolant. I touch the carbide bit up as best I can before using it and it needs a lot of pressure to bite so a drill press is essential and don't be surprised if the carbide just disintegrates before your eyes.

[jack620]

Thanks Bob,
My worry with a masonry bit is the interrupted cut (due to the rebates in the sides of the vice) will knock the tips off. I've got loads of masonry bits in my collection, so I'll sharpen one of them up and test it on some hard steel. According to the seller of the vice it is hardened to 58-62 HRC.

How about one of these 2 flute slot drills? Only $12 for the 8mm:
CARBIDE SLOT DRILL HRC45 - 2 FLUTE - TiAlN COATED - METRIC #G66 (http://www.ctctools.biz/servlet/the-386/TiAlN-Coated-Tungsten-Micrograin/Detail)

[Michael G]

As far as the overhang goes, you are probably only talking about increasing it 10 or 12mm, so I wouldn't be losing sleep over it. (after all, it is only a bit of plate wider than the vertical slide so that you can get a clamp onto the vice

You could use a carbide drill, but the slightest bit of movement could kill it as they are brittle. For that to work you would need a good solid mill.
I would try the false table first - I'd rather spend money on a bit of steel that I could reuse for something else if it didn't work rather than potentially damage a drill and/or vice.

Michael

Added bonus - just looking at the photos again - a false table will give you extra clearance for the vertical table handle.

[jack620]

OK Michael, sounds good.
Bear with me, this is all new to me. What sort of clamp are we talking about to secure the vice to the adaptor plate?
And... is there a particular type/grade of steel plate I should be trying to track down? Something flat obviously.

[krisfarm]

jack 620
I hold my vise similar to yours by clamping into the side grooves that you will be trying to drill through. I think you will be buying trouble trying to drill down through those grooves, lots of broken drills and run of of your holes.
Bob

[nearnexus]

Hi Chris,

I did exactly what you are suggesting with an engineers vice much like yours on my vertical mill slide, for milling on my lathe (my only milling option).

Works great. I have three sets of holes in mine so I can move it up or down on the mill slide.

I just used an end mill in the drill press.

That was a long time ago, and from memory I don't think it did the end mill much good, but it worked.

It weakens the vice base a bit as you are drilling out quite a bit of metal to countersink the Allen heads, but there doesn't seem to be any issue once it's pulled up against the mill slide.

You can't use a slot mill as it won't /can't mill out the very centre section when plunging - must be an end mill

Correction: you could use a slot mill if you first drilled out the centre section of where you intend milling - ie. drill the bolt holes through first.

If I did it again I would reduce the depth of the Allen head as much as possible by machining off the top and bottom of the head . That way you won't have to countersink so heavily.

Cheers

Rob

[Michael G]

Something this -
http://www.woodworkforums.com/attachment.php?attachmentid=240105&d=1352454523&thumb=1&stc=1

Michael

[Stustoys]

I'm with Michaal, though,
maybe 4 clamps?
why not a thread hole instead of a nut?
The clamps more like this maybe?

Stuart

[nearnexus]

If you're going to use clamps, why not just mill up something to fit into the slots on the side of the vice (see photo) and clamp it straight onto the millslide with the T slots?

Probably why they put the slots there in the first place.

Rob

[jack620]

Rob,
that is what I was starting to think. Dispense with the adaptor plate and just make a pair of extra long t-nuts that extend beyond the sides of the slotted table. Screw the "clamps" directly to the t nuts?

[nearnexus]

That, or mill up a couple of right angle narrow plates that fit the slots each side and drill through those for the Allen headed bolts into nuts in the T slots.

Sounds good to me, just make sure there is no twist when you pull them down. The only issue is whether the mill slide table is wide enough to let all this happen :)

That's a nice looking vice - how much $$s and where did you get it ?

Engineers vice is one very handy item.

Rob

[jack620]

Now I just have to work out how to mill without a mill. :)

I reckon I can make the t-nuts and clamps by securing the stock in my toolpost with appropriate shims. It will have to wait till Monday when I collect my 11-12mm ER40 collet from the post office. I tried holding a milling cutter in the 3 jaw and it worked its way out and stuffed the job.

Edit: Rob, I got the vice from this bloke: 63mm-2.5" QGG Screw Guide Precision Toolmarker's Vise (Free Postage) | eBay (http://www.ebay.com.au/itm/63mm-2-5-QGG-Screw-Guide-Precision-Toolmarkers-Vise-Free-Postage-/350634109226?pt=AU_Hand_Tools&hash=item51a36be92a&_uhb=1#ht_500wt_1363)

[Ueee]

Rob,
that is what I was starting to think. Dispense with the adaptor plate and just make a pair of extra long t-nuts that extend beyond the sides of the slotted table. Screw the "clamps" directly to the t nuts?

I looked at this thread earlier and came to the same solution that the long t nuts would be my first choice. If it fails at least you can cut the t nuts up into normal sized ones

[nearnexus]

See the description in the Ebay write up:

"can be used on 4 different sides, including pull-down system"

That's what the slots are there for.

Rob

[Clubman7]

Could maybe drill holes with these.

Artu Drills

"ARTU" DRILLS are stocked and sold for drilling up to 70Rc hardened steels. These unique drills look like a masonry drill but will drill through a file. They can handle the heat up to 1000'C. Great for removing broken drills and taps; the set 4 - 12mm is a must for tool rooms and maintenance shops alike.

ALL PURPOSE DRILL FOR ROTARY OR PERCUSSION DRILLING



DRILLS JOBS OTHER DRILLS CAN'T DO

Made from specialised material designed to give long wear life in a variety of materials
EASILY RESHARPENED on ARTU grinding wheels
DRILLS EASILY THROUGH
- hardened steel up to 70 HRC
- iron
- steel reinforced concrete
- concrete
- some cast metals
- stone & bricks
- springs
- bearings
- granite
- marble
- tiles
- baked ceramics
- fibreglass
- glass
- plastics

Metric & imperial sizes from 3.0mm -25mm or 1/8" - 1" in standard, long and extra-long lengths.
Available singly or in sets of 5 metric sizes or sets of 7 in either metric or imperial sizes
Also available: ARTU special carbide tipped hacksaw blade and rod saws - fit any hacksaw frame

[nearnexus]

I wonder if face plate clamps would fit the slot?

Rob

[Bryan]

I went through this process a while back and made an adaptor plate and pin clamps. Here's the thread: http://www.woodworkforums.com/f65/how-mount-vise-lathe-milling-122363/ . It includes some sketches but not a shot of the finished product for some reason. I will see if I can find a pic. It worked quite well. I wouldn't drill the vice.

Edit: This is the best pic I can find. Obviously you would need flat clamps.

240130

[Stustoys]

If you go straight from the slot to a Tee nut you will be clamping to a cantilever. A cantilever with a large hole in it. The point of failure might be the end of the tee slot casting breaking.

Stuart

[Michael G]

I second Stuart's thoughts - a long T nut cantilevered out runs the risk of damaging the T slots. The set-up I've drawn or that Bryan has made will keep your T slots in compression. Much safer.

Chris, milling without a mill is called a hacksaw and file. You can always make up something basic and then replace it once you can mill.

Michael

[jack620]

That's what the slots are there for.


Rob,
I knew what the slots were for, I just couldn't figure out how to use them given that the slotted mill table is only slightly wider than the vice. The adaptor plate idea overcomes that limitation.


I went through this process a while back and made an adaptor plate and pin clamps. Here's the thread:

Thanks Bryan,
I'm glad to see I'm not alone. Yours looks like a good setup.


I second Stuart's thoughts - a long T nut cantilevered out runs the risk of damaging the T slots. The set-up I've drawn or that Bryan has made will keep your T slots in compression. Much safer.

Yep, I was lying awake last night wondering about the possibility of the extended t-nuts flexing up and breaking off the ends of the t-slots. Looks like it's back to the adaptor plate idea. I reckon it needs to be 100mm wide. So a short piece of say 100x12 or 100x16 BMS should so it. Hopefully Lockbar will have some in stock.

Chris

[mike48]

Artu Drills

if you decide to drill with these, or with a sharpened masonry bit, the website for the manufacturer Artu gives drilling and sharpening instructions.
You could sharpen a masonry bit to act like an Artu bit.
The Artu site says the bit insert material is a mix of cobalt and tungsten carbide, but this is true of most drills of this type, so dont be put off if you use a masonry bit.
The cobalt material acts as a binder for the sintered tungsten carbide during manufacture.
The cobalt material is quite poisonous by the way.
Check it out on Wikipedia et al.
Use a particle and fume mask when grinding any carbide.

A few years ago I bought one of these Artu bits in 1/4 inch at the Brisbane Woodworking Show, and as you do, I asked the demonstrator, what the best method was for drilling hard steels.

He said "have you noticed that when I drill files as a demo, I am using a high speed electric hand drill (it was in a mini drill press attachment) , at 2500-3000 rpm, and that is the best advice I can give ".
I also noticed that he used medium to heavy feed pressure, rather than take a light cut.
The other thing that he mentioned (or rather hinted), was that there are no secrets about Artu drills, mostly good marketing techniques. It is all about carbide tips, tip sharpening angles, both cutting and relief, and cutting speed. My Artu bit has a ground back angle on the cutting face of about 15 deg, so that it is "dragging" on the material to be drilled rather than cutting into it like normal HSS and full carbide drill bits.
The Artu website info seems to back up the demonstrator, as it suggests 2000 rpm for hard steels.

These Artu drills do work, but the cutting tips do fracture also.
I use a diamond hand hone on masonry bits to touch up these type of bits; very easy with medium cut then fine cut.

cheerio, mike

edited for maily typos

[jack620]

Thanks Mike. Good info.

[jack620]

Well I bought myself a piece of 4" wide 1/2" thick BMS to make the adaptor plate and today I drilled 4 x 8mm holes for the screws that will engage the t-slot nuts in the milling attachment. Now I need 2 x 75mm long t-slot nuts. Today I tried to devise a way of making these using the toolpost but I can't think of a safe way to do it. The photo shows my setup.

Since I have no vertical adjustment I would need to shim under the stock after the first pass to make the "ears" of the t-nuts the correct thickness. When that's done I would flip the stock around and make the cuts to produce the "ear" on the other side. However I don't think there will be enough metal left to screw the toolpost screws down onto once the first side is milled. I'm worried I will get the job 90% done and have it ruined if it dislodges.

Can you guys offer any ideas that may have eluded me so far?

Chris

[Ueee]

Hi Chris,
Just tap some flat bar that fits in the t slots so that you can put the vise on and then make proper t nuts.

[matthew_g]

A sharpened masonary drill is no different to the Artu drill but a fraction of the price.
I have used sharpened masonary bits to drill through high speed steel, High carbon steel and
even proved to a mate that you can drill a file with them.
Just keep them sharpe (I use a drill doctor) and you wont go wrong.
Just my 2c worth
Matt

[Michael G]

Firstly, from your photo. Do not wind the material into the cutter like that - because there is backlash you will potentially break your cutter and/ or damage the job. You need to position the material so you are feeding out when cutting on the top like that.

As for holding, As Ewan says, make up some strip from flat bar as a temporary hold down. The other option is to make up some t nuts on the lathe. Turn up a hat section. Make the 'brim' of the hat wider than the width of the wider part of the T section and then using a hacksaw and file trim it to fit. That way it will not rotate.

Michael

[jack620]

Thanks Ewan & Michael. If I have some flat I'll use that. If not, I'll turn some up and file flats on the sides. Apologies if that has already been suggested. I think my memory is on the way out.

Michael I know about not making "climbing" cuts (I learned the scary way on the router table). The lathe is not operating in the photo.

Matt,
thanks but I'm not going to attempt drilling the vice.

Chris

[Anorak Bob]

Thanks Ewan & Michael. If I have some flat I'll use that. If not, I'll turn some up and file flats on the sides. Apologies if that has already been suggested. I think my memory is on the way out.

Michael I know about not making "climbing" cuts (I learned the scary way on the router table). The lathe is not operating in the photo.

Matt,
thanks but I'm not going to attempt drilling the vice.

Chris

Well that brings back some nasty memories. A hand held 1 1/2 horse Makita. Instant destruction with the flick of a switch. FM!

B still cringing 20 years later T

[Big Shed]

My vise is slightly different, but the clamps I made for it would work with yours with a minor mod, instead of the pin just mill a step.

http://www.woodworkforums.com/f65/screwless-vise-139279/#post1358128

[sgtfoxhound]

I bought a new vice to mount on my recently acquired Hercus milling attachment. I intend drilling 4 holes through the vice to allow 8mm socket head screws to pass through and into 2 long t-nuts. The holes will be stepped to allow the heads of the screws to sit below the surface of the vice's base.

Today I started marking out for the holes and discovered that the vice is made from VERY hard steel. My scriber barely scratches the surface. Likewise a file. There is the added complication of the rebates along the sides of the vice potentially causing a twist drill to be pushed off line (assuming a twist drill will even do the job).

Due to the narrow width of the two 'rails' of the base, the holes will be partially in these rebates (i.e. the screws will be exposed). That doesn't bother me as long as I can drill the holes straight.

Should I consider a solid carbide drill bit or maybe a slotting mill? Or will a cobalt twist drill will do the job? I want to get this right, so I'm not keen on just jumping in and stuffing up a good vice.

Chris


try sharpening a masonary drill like an end mill find a drill that will drill a hole in a ball bearing

[Anorak Bob]

Chris,

I've been thinking about this and being an exponent of doing the least when you can get away with it, here's a lazy way of mounting the vice along the lines of Michael G's drawing. No milling involved. A strip of flat bar threaded M6 or a 1/4" can replace the tee nuts in the Hercus slide table. I say this because it is all I ever used to secure my little home made vice to both the vertical milling attachment and the No.O mill table. I never shook the thing loose.

The photos should explain the rest. This mickey mouse setup should suffice until you can mill the clamps you require. The Waldown vice is a stand in. I don't have a grinding vice. The first photo show's the robust hold down clamp supplied with that vice.

BT

[jack620]

A hand held 1 1/2 horse Makita. Instant destruction with the flick of a switch.

Yep, I have a Makita in my router table. And being a Makita, it has the horrendous noise that seems to afflict all power tools made by that manufacturer. That and crappy little switches and cords that are too short. Still are they are solidly built.

Thanks again for the replies. As I don't have any 3/16 x 5/8 bar I'll turn up some t-nuts are per Michael's suggestion. I think I'll use Bob's 2 piece clamping arrangement to hold the vice to the adaptor plate. Then I'll be in a position to make 'proper' hold-down clamps like Big Shed's and some t-bars.

Chris

[jack620]

One down, three to go.

[Michael G]

:2tsup:

Michael

[jack620]

Thought I'd better provide an update on my progress after all the input you guys gave me. I've got the vice mounted on the milling attachment using the adaptor plate method. It's currently held down by 4 temporary clamps. I'll make proper ones out of 25x25 MS if I ever receive the ER40 collet spanner I ordered on eBay nearly a month ago. :((

Because I can only hand tighten the collet nut I've been milling soft stuff like Delrin and aluminium. I can do MS if I take very light cuts.

The milling attachment is a great addition to the lathe.

Chris

[beefy]

Thought I was just about the only one who knew about drilling hardened steel with masonary bits, ha ha.

Anyway I'll just throw in how I was told to do it. It may not be the best but it has worked a lot for me. I didn't sharpen the bit and I used the fastest speed my drill press would do. I flooded the bit with coolant so the brazing would not melt, but the high rpm and the pressure causes the hardened steel to heat up and soften at the point of contact. Nothing happens for a few seconds then all of a sudden it starts drilling through.

Mitre 10 have some Bosch multi-purpose "masonary" bits in blue packs. Basically seem like a sharp masonary drill bit as a few have mentioned here. I've used these with success on hardened steel too.