# How would you drill holes in the end of a long plate?



## bpimm (Mar 24, 2017)

I need to drill and tap 3 holes in the end of a 4" X .5" plate that is 14" long to match another part that mounts with 10-32 screws. This is part of the new Z axis I'm building for my plasma table.

I was thinking of making a drill guide out of mild steel on the cnc to get the spacing right and clamp it on the end then hand drill. 

Any better ideas? here is the part the holes mount the plate the motor is on to the vertical plate that is blue.







Thanks for any advise
Brian


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## chips&more (Mar 24, 2017)

What tools -machines do you have to do the job?


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## Bob Korves (Mar 24, 2017)

If you have access to a milling machine with a turret to drill with, I would clamp and square the work to the side of the table, and then swing the ram for clearing the knee with the work.


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## brino (Mar 24, 2017)

Whatever you use to get the first hole aligned, I would finish tapping the first hole and bolt it before moving to drill the next hole and continue in this manner. That is, use the final fasteners as the "clamp" to keep the pieces aligned as you go along. I have had much better alignment when following this practice.
-brino


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## RJSakowski (Mar 24, 2017)

I take it that your motor mounting plate is already made.  Typically, I would use the technique used by medieval locksmiths who made the lock to fit the key.  I would drill and  tap one hole and mount the motor plate to use it as a template for the second mounting hole.  If your other holes are already made, I would do the complete assembly up to get my alignment as close as possible.  I would clamp the assembly as well as I could and then drill and tap the first hole.  Then I would bolt that hole up to further define the alignment and drill and tap the second hole.

Of course, having a CNC, you can make a jig to accomplish the same thing.  A little more work up front but easier and potentially better results on the back end.  As for the actual drilling and tapping, if you have a drill press with enough clearance, you can swing the table to the side and use Bob's clamping approach to drill and tap.  Or you can make your jig an inch or so thick which should be sufficient to make the holes run true and use the hand drill.


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## RJSakowski (Mar 24, 2017)

brino said:


> Whatever you use to get the first hole aligned, I would finish tapping the first hole and bolt it before moving to drill the next hole and continue in this manner. That is, use the final fasteners as the "clamp" to keep the pieces aligned as you go along. I have had much better alignment when following this practice.
> -brino


Damn, Brino, you type faster than me!


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## bpimm (Mar 24, 2017)

chips&more said:


> What tools -machines do you have to do the job?



I have 2 drill presses and 2 mills to work with besides the standard hand tools. See below.



Bob Korves said:


> If you have access to a milling machine with a turret to drill with, I would clamp and square the work to the side of the table, and then swing the ram for clearing the knee with the work.



Bob, if I'm understanding you correctly you are suggesting swinging the head so it is no longer above the knee and has access to the back edge of the table. I could do that on either mill. One is a round column benchtop Grizzly RF clone that has been converted to CNC, I'd have to remove the flood coolant containment box from the table on this one but it's really easy to swing the head and I already have the hole pattern programed for it.






Or I have a Jet Knee mill that could do that as well, needs a little cleaning.





This one can swing the head and I can use the DRO for the drill pattern so I guess either can do it so it boils down to which is easier to set up.


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## bpimm (Mar 24, 2017)

RJSakowski said:


> I take it that your motor mounting plate is already made.  Typically, I would use the technique used by medieval locksmiths who made the lock to fit the key.  I would drill and  tap one hole and mount the motor plate to use it as a template for the second mounting hole.  If your other holes are already made, I would do the complete assembly up to get my alignment as close as possible.  I would clamp the assembly as well as I could and then drill and tap the first hole.  Then I would bolt that hole up to further define the alignment and drill and tap the second hole.
> 
> Of course, having a CNC, you can make a jig to accomplish the same thing.  A little more work up front but easier and potentially better results on the back end.  As for the actual drilling and tapping, if you have a drill press with enough clearance, you can swing the table to the side and use Bob's clamping approach to drill and tap.  Or you can make your jig an inch or so thick which should be sufficient to make the holes run true and use the hand drill.




Yes the motor mount plate is done but the holes in it are clearance holes and wouldn't center the tap drill well, I could transfer punch it and drill but my accuracy that way would be suspect. 
My floor standing drill press can swing and rotate the table to do this but both my drill presses are on the cheap side and kind of sloppy.


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## bpimm (Mar 24, 2017)

brino said:


> Whatever you use to get the first hole aligned, I would finish tapping the first hole and bolt it before moving to drill the next hole and continue in this manner. That is, use the final fasteners as the "clamp" to keep the pieces aligned as you go along. I have had much better alignment when following this practice.
> -brino



I have done this in the past definitely good practice.


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## wawoodman (Mar 24, 2017)

You could make a plate to hold a hardened drill bushing, and clamp that to the workpiece.

For that matter, if it's just three holes, make a guide out of some 1/2" aluminum. That will hold your bit straight enough for the tapped holes.


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## Silverbullet (Mar 24, 2017)

I'd say if you want accurate holes use the mill . If you want working holes use a drill press and clamp to an angle plate leveling to match your drill press. I'm old school I'd layout and center punch first then drill . Guess ill never change that way I know my lay outs are right if the drawing is , yes I've caught messed up drawings too. But it's also saved me a time or two. When I was right and the part made was wrong , the they say make it fit. But my tails covered.


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## tq60 (Mar 24, 2017)

Clamp scrap to already made part and use following size drill first to "spot" the hole then drill with small drill.

This is now pattern.

Use it to drill holes in another chunk of scrap to test fit.

Drill first 3 small holes then remove guide and finish drill and tap then test fit.

If fit then repeat on final chunk.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk


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## Silverbullet (Mar 24, 2017)

Remember the machines only as good as the guy using it.


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## bpimm (Mar 24, 2017)

Silverbullet said:


> Remember the machines only as good as the guy using it.


 That's my concern... LOL


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## Rustrp (Mar 24, 2017)

My first thought; Do you have vertical clearance between the vice and the head of the mill? Then my head starts working on the different methods to fabricate a rigid fixture to clamp in the vise to clamp your plate to. I always add welding into the mix if that's an aption you have. Based on the thread size holding the position is the most critical so I see a fixture similar to this;

https://www.weldsale.com/product/wsknee1012/

If you don't have the clearance then as Bob and others have commented shift what you need too so the piece hangs off the side of the table.


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## RJSakowski (Mar 24, 2017)

I see that the cover for your mill/drill occupies the same position as mine does.


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## bpimm (Mar 24, 2017)

RJSakowski said:


> I see that the cover for your mill/drill occupies the same position as mine does.



That thing made more rattling noise than a rock crusher, it was actually impressive how loud it was.


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## talvare (Mar 24, 2017)

One more option would be if you have a 90 deg. milling attachment for that Jet mill. You could clamp your plate to the mill table set up on some 123 blocks and horizontally drill the end of your plate.

Ted


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## bpimm (Mar 24, 2017)

Don't have one of those...


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## bpimm (Mar 24, 2017)

Bob Korves said:


> If you have access to a milling machine with a turret to drill with, I would clamp and square the work to the side of the table, and then swing the ram for clearing the knee with the work.



This is what I ended up doing, worked great.












Now to finish the rest.


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## whitmore (Mar 24, 2017)

Silverbullet said:


> I'd say if you want ... working holes use a drill press and clamp to an angle plate leveling to match your drill press. I'm old school I'd layout and center punch first then drill .



Yes, the angle plate is quicker than trying to re-level the drill press table after tilting it.

One could also clamp the work between 2 x 4s (or 1-2-3 blocks or whatnot) and use
a Portalign type drill guide.   The guide rods can be used to center, and the base will
keep it square against the 2 x 4s.   Figure 3 in the patent illustrates this method
<https://www.google.com/patents/US3874810>


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