# Need to make a big hole in Aluminum plate



## Investigator (Jun 11, 2018)

I need some suggestions please, I need to 'bore' a 2-2.5" hole in 1.5" aluminum plate.

I'm working on a steady rest, my lathe didn't come with one.  To that end I have acquired a piece of 1.5" aluminum (6061-t6 I think) which is 6x10", as well as some brass 'fingers' for the rest.  I have pretty much worked out the steps I need to do everything but make the 'big hole'.  I have a 12" Logan lathe and a RF30/31 mill to work with.

I think what I need to do is drill then bore it to size on a mill.  Trouble is I have no boring head or tooling.  Is there another way? Or do I need to bite the bullet and buy a boring head to do it?

Scott


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## David S (Jun 11, 2018)

Let me be a bit crude, but could you drill a series of holes around the circumference of the hole and then cut out with a jig saw, and finish in the lathe?

David


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## benmychree (Jun 11, 2018)

Get someone to water jet cut it, they could shape the whole works for you.


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## Dave Paine (Jun 11, 2018)

The drill holes and use jig saw method of David S. could work, but you need to go slow with the jig saw.   I tried using my jig saw on some 1/2in aluminium and within seconds the blade gullets were filled with cold weld particles.   I had to pick these out one at a time then go much slower.

Another option is to grind a trepanning tool.

A Tom Lipton (Oxtool) video on this topic.

Tom Lipton video on trepanning tool


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## Investigator (Jun 11, 2018)

I don't think turning the piece itself on the lathe is an option, at least not the way I am planning on making it.  I could possibly make a tool on the lathe to cut the hole in the mill though. 

The drill and jigsaw idea would likely work, but I'd rather do a more elegant and precise method if it's available.


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## benmychree (Jun 11, 2018)

Dave Paine said:


> The drill holes and use jig saw method of David S. could work, but you need to go slow with the jig saw.   I tried using my jig saw on some 1/2in aluminium and within seconds the blade gullets were filled with cold weld particles.   I had to pick these out one at a time then go much slower.
> 
> Another option is to grind a trepanning tool.
> 
> ...


One should always use a lubricant to avoid chip welding with aluminum; kerosene is the old standby but Magic Tap works well and is not so smelly.


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## GoceKU (Jun 11, 2018)

Scott, the simplest way i can think off is to go to a friend or a fellow machinist with a bigger lathe that can swing the whole piece around, drill and thread the centre of the hole then attach it to a mandrel and use an parting and grooving tool to part it off, for aluminium hand ground hss tool should be fine https://www.sandvik.coromant.com/Si...arting-grooving/face-grooving-tools-thumb.jpg


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## Investigator (Jun 11, 2018)

Thinking off the wall here.....

I have a small rotary table.  What about mounting it so that I could turn it under the mill head, and cut with an end mill?


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## DAT510 (Jun 11, 2018)

You could also use a hole saw, though the surface finish won't be the greatest.  Drill/Hole Saw then boring would get you the nicest finish.  If you get a boring head for your mill, as long as it doesn't have a fixed arbor, there are a variety of additional uses, such as a ball turner or as a means to further offset your tail stock, that you can use it for.


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## benmychree (Jun 11, 2018)

That could work, (doing it on the rotary table) but likely you'd need to cut from both sides due to the thickness, same would go for trepanning. A hole saw is a option, also going at it from both sides.


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## DAT510 (Jun 11, 2018)

Investigator said:


> Thinking off the wall here.....
> 
> I have a small rotary table. What about mounting it so that I could turn it under the mill head, and cut with an end mill?



That would work..


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## kd4gij (Jun 11, 2018)

https://www.homedepot.com/p/Diablo-...apLock-Plus-Mandrel-System-DHS2500C/206797332


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## Mitch Alsup (Jun 11, 2018)

Investigator said:


> Thinking off the wall here.....
> 
> I have a small rotary table.  What about mounting it so that I could turn it under the mill head, and cut with an end mill?



How small?

You are going to need clearance off the table so the end mill does not eat the table as the part turns around.
You are going to need a means to hold part to table while milling.

Other than that:: perfect.


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## MarkM (Jun 11, 2018)

Locate your hole with your mill by drilling and then put a boring bar in a collett that will enable you to true up the hole.  Either a fixed bar or use a bar that takes high speed.  True the hole up then put it in your four jaw on the lathe and indicate the hole then your hole place is accurate.  Now either bore the rest or use what you have to get close like a holesaw if you don t Have any big drills.  I wouldn t trepan a hole that deep as everything has to be spot on when treppanning and the tool needs to be done well.


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## P. Waller (Jun 11, 2018)

I have no idea what a RF 30/31 mill is but can you not interpolate such a small hole?

If not use a cheap fly cutter as a rough boring head after a hole saw or drill has made a starting hole, use a dial indicator to set the tool diameter.
This is slow and tedious but you only require one part correct?


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## pdentrem (Jun 11, 2018)

These are 2 possible ways I would do this job. The Wire EDM machine would love this easy job but you have what you need to do the job.
I would use a 2 flute 3/8 or 1/2” end mill made for Aluminum. Rotary table with a 1/4” sacrificial piece of plywood or plastic cutting board. Bore your center hole which will be used to locate on center of rotary table. Use a 2 flute end mill and work down to pass half way, like about 1/4 to 1/2” from bottom. or cut through into that sacrificial plate.

Careful please read this part!
You do not want the center piece to break loose and trap the end mill as you approach the end of the cut. So with leaving 2 small retaining tabs about 180 degrees apart to hold the center plug in place. When done you should have a plug that is cut all the way except for two small areas that you can cut with a small saw and then blend into the rest of the cut.

Or flip before completely cutting through and avoid the sacrificial plate and cut down to about 1/4 to 1/2” left and flip, locate on the center hole again and continue to clear the remaining part but still leave the retaining tabs to hand cut at the end.


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## pdentrem (Jun 11, 2018)

If the rotary is too small, Make an adapter that will allow the steady rest to mount to the rotary table. 1/2” Baltic plywood comes to mind as I have use this stuff for jigs and mounts quite a bit.


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## eserv (Jun 11, 2018)

I'd do it with a holesaw as already mentioned. It'll be slow and you will need to clean out the chips often but you'll have a nice "slug" left to make something else out of!    Best if you could do it horizontal.


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## Eddyde (Jun 11, 2018)

A fly-cutter will work like a boring head, it's just harder to adjust. Here is a video of using one to cut a relief but it works for holes as well 



Make the initial hole with a hole-saw.


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## jim18655 (Jun 11, 2018)

If you use a hole-saw try drilling 3 or 4 1/4"  holes on the kerf of the saw. It gives the chips a place to fall through and out of the way.


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## Investigator (Jun 11, 2018)

P. Waller said:


> I have no idea what a RF 30/31 mill is but can you not interpolate such a small hole?


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## Investigator (Jun 11, 2018)

going now to google "interpolate".........


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## Investigator (Jun 11, 2018)

pdentrem said:


> ................................
> 
> Careful please read this part!
> You do not want the center piece to break loose and trap the end mill as you approach the end of the cut. So with leaving 2 small retaining tabs about 180 degrees apart to hold the center plug in place. When done you should have a plug that is cut all the way except for two small areas that you can cut with a small saw and then blend into the rest of the cut.
> ...



Thank you! that is not something I would have thought of.


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## Jimsehr (Jun 11, 2018)

When I made a steady out of alum I made the bottom of steady first . Then I put it on the machine with the hold down bolt snug. Then I drilled steady with a 1/2 drill in a collet by pushing alum into drill with tailstock. That way I knew 1/2 hole was on center of machine . Then I used that hole to center steady on rotary table. I worked from that hole to cut the 3 slots for the steady fingers. Then I cut the center plug out.


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## JimDawson (Jun 11, 2018)

Investigator said:


> Thinking off the wall here.....
> 
> I have a small rotary table.  What about mounting it so that I could turn it under the mill head, and cut with an end mill?



That's how I would do it given your available tooling.


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## tq60 (Jun 12, 2018)

Rent a hole saw from a rental place or buy one as they are handy to have. 

Place wood under it clamped tight to table.

Slowest gear possible and peck drill.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk


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## Investigator (Jun 12, 2018)

I was under the impression that a hole saw cutting that deep in aluminum was a problem.  But that does look like the easiest solution.  I have several hole saws already but hadn't really considered using one because as I said I thought it was somehow an issue.
I guess going slow and lots of cleaning out of chips would work and might be the easiest set up.


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## RandyM (Jun 12, 2018)

Use a lubricant. I use WD40 for aluminum. You'll still have to clean the chips out of the cutting very often. I think the hole saw is really your best choice.

Another tip for this is to cut half way thru one side and then flip the part over using your pilot hole to line it all back up. This will keep the saw groove from getting so deep.

Good luck.


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## Investigator (Jun 12, 2018)

Another, albeit late thought.  What would be the preferred size opening for a steady rest?  Put another way, what size stock should I plan on being able to handle?

Talking this through in my head......My spindle is 1.375", so it seems there really is no value in making a steady for smaller than that since it could fit through the head stock and work close to the chuck.  I guess making the steady large enough to handle a range from 1.375"-? would be a better plan. 
So, 2.5"? 3"?  does it matter how much of the fingers are extended past the rest?
Maybe the best design criteria would be what size hole saw I have readily available?


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## pontiac428 (Jun 12, 2018)

I cut a hole in 1.5 in aluminum plate with a hole saw... Once. Never again. I'd suggest hogging the hole out with a S&D bit then using a boring head or a fly cutting head in the Rong Fu. Rotary table would work well too.

Sent from my HTC U11 using Tapatalk


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## Investigator (Jun 12, 2018)

pontiac428 said:


> I cut a hole in 1.5 in aluminum plate with a hole saw... Once. Never again.
> 
> Sent from my HTC U11 using Tapatalk



What was the issue that turned you off of that method?


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## pontiac428 (Jun 12, 2018)

I used a hardware store saw and arbor that wasn't very round or concentric, but the main issue was side wall friction and chip clearance. It took over an hour. Simply the wrong tool for the job. I might have a photo in the archive somewhere. It was a pretty ugly result. That was ten years worth of learning ago, and I haven't dared consider it since. 

Sent from my HTC U11 using Tapatalk

Edit:. I found a pic of the plate, but I must have skipped the pic after the hole saw debacle.


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## Eddyde (Jun 12, 2018)

A hole saw will work fine if, as mentioned above, peck and use WD-40 or Kerosene. Also for that thickness I would cut it from both sides.
Edit: A quality hole saw and arbor.


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## DAT510 (Jun 12, 2018)

After cutting with a hole saw, if you are not happy with the surface finish, you could then use your Rotary table idea to take a finish cut to clean it up.


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## Downunder Bob (Jun 12, 2018)

Is it for the 12"logan?


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## Investigator (Jun 12, 2018)

Downunder Bob said:


> Is it for the 12"logan?



Yes


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## projectnut (Jun 12, 2018)

Personally I would enter the piece on the rotary table with a couple of 1" parallels under it.  then center where the hole is to be bored under the quill .  Next drill a center hole through the plate with the same size bit as the hole saw pilot.  Be sure to note the coordinates if you have a DRO, or zero the dials if you don't have a DRO.  

Using a hole saw slightly smaller than the finished hole make a slight to serve as an outline.  Move the mill table to align the caw cut with the quill.  Rotate the table drilling several 3/16"holes around the perimeter using the saw cut as a centering point.  Reinstall the hole saw, move the mill table back to the zero point and cut through the plate using the pecking method and plenty of WD 40 as a lubricant and flush.  Once the core is removed insert a mill in the quill and move the mill table to the proper position to cut the desired diameter.   Rotate the table to finish the cut.  Depending on the size of the original hole and the size of the end mill used for finishing you might want to make more than a single finish cut.


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## ezduzit (Jun 12, 2018)

The steady I have for my 12" Logan can handle up to nearly 4" diameter. I would not want to limit myself to much less than that.

Also I would use the rotary table for producing the hole. The attached photo shows a part I made on my rotary table. The rounded portion fits inside a 4" diameter sailboat boom (so its  would be ~3-5/8") and was hollowed out using a 5/8" carbide end mill.


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## dennys502 (Jun 12, 2018)

The steady rest I made could handle 5" pipe. I made it that big so I could face the ends of pipe if I needed to.
It all depends on usage.


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## derf (Jun 12, 2018)

Here's one I made for my 10" SB, and then an adapter for my 13". It's been a long time ago, but I think I just drilled some 3/4" holes and freehanded the rest on the mill.


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## pineyfolks (Jun 12, 2018)

The hole in the steady rest is only for clearance. You could mill a square or hexagon hole in it and it'll still work fine. You're using the fingers to center the workpiece.


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## whitmore (Jun 12, 2018)

Investigator said:


> I have a small rotary table.  What about mounting it so that I could turn it under the mill head, and cut with an end mill?



Yes, that'd work; you'd want to start by making the lathe bed-base part, affix the plate to it, and use the lathe to
drill an accurate center hole, to use in centering the work on the rotary table.

I've considered making a rest that takes a press-in ball bearing race, so I could make adapter inner sleeves
to slip-fit a future project.    If there's a junkbox of big bearings, removed for preventive maintenance,
this can be justification for doing a really accurate circular aperture for your project.


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## stupoty (Jun 12, 2018)

Investigator said:


> I was under the impression that a hole saw cutting that deep in aluminum was a problem.  But that does look like the easiest solution.  I have several hole saws already but hadn't really considered using one because as I said I thought it was somehow an issue.
> I guess going slow and lots of cleaning out of chips would work and might be the easiest set up.



I some times drill from both sides on thick parts , depends if the chips are nice and leaving the hole.  

theirs an rpm chart from starreett to give a guide to speed ,
http://www.starrett.com/docs/other-downloadable-resources/hole-saw-speed-chart---bulletin-194.pdf


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## Dabbler (Jun 12, 2018)

This is old school, but it will give you your large hole.  A steady rest will have to be cut in half anyway, so:
1)  use layout blue to the preferred diameter - sounds like 3" is your best target....
2) make your halving layout and cut with a band saw.
3) continue to take cuts on the band saw until most of the hole is taken out
4) file finish - after all this is just clearance.....


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## P. Waller (Jun 12, 2018)

Investigator said:


> What was the issue that turned you off of that method?


I suspect that chip control was an issue as there is no way to evacuate the chips from the top, this will involve a good deal of pecks.

If indeed one wants to use a hole saw for this purpose make it act like a bandsaw where the chips pass through, drill several through holes where the cut will be and the chips will exit through them clearing the blade, you will find that this approach makes using such a tool almost easy.

Like so.


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## P. Waller (Jun 12, 2018)

As to the size that will pass though a steady you are only limited by the diameter that will allow you to build it and fit on the machine ways.
Often you will  have to turn the ends of a part that will not fit through the spindle yet is short enough to hold in a chuck on one end and the steady on the other, make it as big as possible.

This part would not fit through the spindle but was less then the 100" long would that would fit in the machine, also make it as big as possible in the event that the OD is a finished surface that requires the use of a cats head.


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## homebrewed (Jun 12, 2018)

It seems one apparent limitation of the rotary table approach is the disk you're making in the cut, which could jam once it's free.  But you don't need to do it that way.  Your follower will have some holes in it for mounting the finger adjusting mechanisms, right?  Place them first then use them to mount the plate to a sacrificial piece of plywood.  Mount that on your RT.  Drill the center hole as big as you can, then enlarge the hole by stepping the RT over and milling with your end mill.  It will be -- sorta -- like a boring head setup.  Keep on stepping over and rotating/milling the piece until the hole is the size you want.  You probably want to do conventional milling, not climb milling, with this setup.


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## Silverbullet (Jun 12, 2018)

I to wouldn't just cut the three inch hole, I'd go as big as the piece will handle and leave enough room for the adjusters . And yes I'd start from the bed up , base , ring , adjusters, . Cutting the hole shouldn't be a problem , I'd drill holes close together and near the diameter size . I'd either jig saw by hand or trepan it in the lathe. But your rotary table for you sounds best and yes go from both sides . You can mount it with a sacrificial piece between the part and table to support the size.


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## Charles Spencer (Jun 12, 2018)

Dabbler said:


> This is old school, but it will give you your large hole.  A steady rest will have to be cut in half anyway, so:
> 1)  use layout blue to the preferred diameter - sounds like 3" is your best target....
> 2) make your halving layout and cut with a band saw.
> 3) continue to take cuts on the band saw until most of the hole is taken out
> 4) file finish - after all this is just clearance.....



I like it!  I think that's the approach I would take.


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## kd4gij (Jun 12, 2018)

The one I made for my 12" crafts lathe will hold 4 1/2: stock.


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## strantor (Jun 12, 2018)

Last year I cut two holes through 1" aluminum with a 6" hole saw with a DeWalt wrist-snapper hand drill. It was a hell of a job. It was on a piece of large equipment that would have had to be completely disassembled and sent off for machining, very costly. So we decided to try the hole saw first. I didn't think it would work, but it did. Went at it with plenty of WD40 and stop when the drill gets too hot to hold (or starts smoking from the motor, whichever comes first) then take a 10min break. Repeat.

The surface finish was crap, but would have been better if done in a rigid machine and not by hand.

If it can be done with a 6" hole saw by hand, then surely a 2.5" hole should be no problem for any machine you have access to.


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## markba633csi (Jun 12, 2018)

Yes I would use the lathe itself to cut it, so I would rough cut the hole first then build a temporary mount and fasten it to the carriage.  Then I would build a large flycutter with an adjustable tool bit, mount it in the spindle and start taking light cuts through the hole, running the carriage back and forth, adjusting the flycutter each time.
Painstaking, but will give a beautiful machined surface if you use the power feed. I've used this technique to cut largish holes in 1/8" and 1/4" aluminum.
Also, for a project like this, I would make a fairly detailed drawing since there are many little details to work out and many different design ideas.
Mark


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## NortonDommi (Jun 13, 2018)

If you have the mandrel a hole saw will cost you under $10, use lube, peck drill and have a vacuum cleaner pointed at cut. Swarf is what kills holesaws.
Run at very slow speed as to fast is killer No. 2.
 2 - 2.5" is not a big hole and 1.5" thick can be handled by a standard saw if you buy a long series blade. If you need to extend one just part in lathe and weld in an extension of ERW tube. Make sure the outside is cleaned smooth when done.
  Clean up with a sanding drum and file the edge if you want a really flash finish.


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## coherent (Jun 13, 2018)

I'm assuming you don't know anyone with a cnc mill or this question wouldn't be asked. If you do or can track someone down who does it would be a fairly simple operation.


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## Investigator (Jun 13, 2018)

coherent said:


> I'm assuming you don't know anyone with a cnc mill or this question wouldn't be asked. If you do or can track someone down who does it would be a fairly simple operation.



You're right, I don't know anyone with any equipment whatsoever. 



derf said:


> Here's one I made for my 10" SB, and then an adapter for my 13". It's been a long time ago, but I think I just drilled some 3/4" holes and freehanded the rest on the mill.
> View attachment 269526



This is pretty close to exactly what I plan to do.  I don't plan to make it hinge, just a solid rest.  My plan is to take the plate and put it on the mill table flat/horizontally on risers and true the bottom with an endmill.  Then to remove that set up, and measure/mark the "V" way and put it back in the mill, this time vertically at a 45* angle.  Then to plunge down with the spindle and make the "V" way cut through the length of the bottom.  Then it goes onto the lathe.

On the lathe, I plan to make a center point held in a 5C collet in the lathe.  The plate will be placed on the bed and softly mark the center of the hole.  Off the lathe and use the marked hole placement as well as the true bottom on the rest to lay out 3 slots for the brass fingers 120* apart. Back onto the mill, again on risers and line up the slot and cut with flat end mill, check for fit of finger, and while still set up drill and tap the hole to hold the fingers so it is in the center line of the slot. Repeat for each finger.

Off the lathe, mark the hole better, then use hole saw to make the hole.

I think that will work nicely for what I need, but I don't know what I don't know so if anyone has suggestions I'm open.


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## Mitch Alsup (Jun 13, 2018)

I would suggest that the hole in the SR should be at least as big as the size of a part that can swing over carriage.


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## savarin (Jun 13, 2018)

I use a hole saw for aluminium often.
I clamp the aluminium to a plywood backing and clamp the whole (pun intended) lot onto the drill press table.
Directed wd40 spray and pecking at the drills slowest speed works for me.
Heres some I did earlier.
https://www.hobby-machinist.com/threads/the-giant-binocular.55688/page-3
last post.
I have another sheet to do soon so I will show the actual drilling.


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## kd4gij (Jun 13, 2018)

50 BMG will blow a pretty  big hole in that plate.


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## Dabbler (Jun 14, 2018)

I once had to cut 6 holes in 1/4 " hot rolled steel plate, from 3" to 4".  I used a fly cutter in my mill to do the job...


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## Eddyde (Jun 14, 2018)

kd4gij said:


> 50 BMG will blow a pretty big hole in that plate.


Well a .500" hole. It reminds me when I was a teenager and got my first highpower rifle a .303 Enfield. I shot it at some aluminum plate and was astonished to see the lands and grooves of the rifling perfectly reproduced around the inside of the hole.


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## Asm109 (Jun 14, 2018)

Don't cut the guide slots for your fingers until the center hole is at least roughed out.  That much material removal will cause the part to move.
Don't want that messing with your fits. If it benefits you, you can rough the slots first leaving .015 or .020 to clean up.


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## derf (Jun 14, 2018)

On a previous job about 30 yrs ago, I remember having to cut a 12" hole in a 3/4" steel plate. 
I laid the hole out with blue dykem and drilled a 3/4" hole on the inside. Then proceeded to a 20" bandsaw. The bandsaw had a built in blade welder and grinder. I just broke the blade, threaded it through the work piece, and re -welded it. After I re-installed the blade and cut the hole out, I simply broke the blade and retrieved the work piece. It took less time to weld the blade twice, than to do it any other way.


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## C-Bag (Jun 16, 2018)

I've been lurking this thread because I was getting ready to bore a 1 3/4" hole in a 3"x3"x2 1/2" block of aluminum. Not exactly the same but bigger than I'd done before. I also have an RF-30 and because I also have to mill some flats decided to do the whole thing on it (as opposed to the lathe) because I have a boring head. I also have a 1" drill bit I picked up out of a garage sale thrown in for free because it was messed up. Pushing the boundaries is always a big learning experience and for the first time I was not able to plan around having to raise and lower the head on the mill/drill in middle of the process. I remembered a tip about the laser pointer mounted to the mill shooting across the shop to keep index as I raise and lower the head. After mounting my plumb bob line on the opposite wall and making sure the mill was level I went for it. Works like a champ and the HF laser torpedo level was only $20 with a coupon! It's now staying with the mill and almost looks like part of it. I can't remember who specifically mentioned the laser but I had to send a shout out with my many thanks. And now we return to your usual programming........


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## mattthemuppet2 (Jun 16, 2018)

I would also suggest a hole saw, then clean it up on the rotary table or lathe. Chip evacuation holes are the key to getting holesaws to work - if the inside piece is going to be scrap like here, drill the holes just on the inside of the cut line. Four or 5 1/4" holes should work fine. Then run at a low speed (100-150rpm?) and use lots of WD40 and you find it goes really easy. Another tip is to pre drill the center hole and replace the drill in the arbor with the same size piece of rod, so it acts as a guide only, no cutting.

I've done 1" thick steel plate with a 2 1/2" holesaw. Took 20min or so but it worked fine. Got a nice chunk of steel round to play with too.


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## BGHansen (Jun 16, 2018)

Based on the tools available to you, I'd recommend buying a boring head.  Lots of good ideas above, but you have a lathe and a mill.  You could get close to the right size with a hole saw, but the finish will not be close to what you could do with a boring head.  Plus the boring head lets you make any sized hole within its range.  Once you have it, you'll find other uses.  The 2" import ones with 1/2" 9 pc. boring bars go for under $85 on eBay including shipping.

You have a good idea with the rotary table too.  I've made holes and outside radii on pieces using an RT.

Bruce


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## Charles Spencer (Jun 16, 2018)

derf said:


> On a previous job about 30 yrs ago, I remember having to cut a 12" hole in a 3/4" steel plate.
> I laid the hole out with blue dykem and drilled a 3/4" hole on the inside. Then proceeded to a 20" bandsaw. The bandsaw had a built in blade welder and grinder. I just broke the blade, threaded it through the work piece, and re -welded it. After I re-installed the blade and cut the hole out, I simply broke the blade and retrieved the work piece. It took less time to weld the blade twice, than to do it any other way.



Many years ago I worked at a cutting die shop where we made credit card and label dies using that process on a DoAll saw.  It was the fastest way to remove the stock on the manual machines we had.


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## Jimsehr (Jun 16, 2018)

There is no law that says hole has to be round. You could drill 4 holes and cut out a square hole if you want. Or look at post #40 and think of a rectangle shape opening. Cut the 3 slots before the clearance hole.


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## kd4gij (Jun 16, 2018)

Don't pass up an opportunity to buy new tools. Get a boring head with boring bar set and a good hole saw.


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