Advanced Grinding Rest (Harold Hall)

[Kim]

Thanks Dave and Don

[Jo]

Anyway, if you couldn't tell, I'm quite tickled with the Drill Jig. It's the coolest little gadget I've made with the Grinding Rest.  I can't believe that I had considered skipping this part!  It's well worth it!

Nice, now I have no excuses I will have to learn how to cut/sharpen four facet drills on my own cutter grinder.

Jo

[Arbalest]

Nice job. I'm going to have to sit down and digest the technique.

[joe d]

Kim

I really enjoyed following you along on this, I think I need to move it up on my "Need to build one" list,
might finally get to the cookie tin full of semi-retired drill bits

Incidentally, I really like the brass shield you've made for the grinding wheel, looks really good!

Joe

[Kim]

Thanks Jo, Arbalest, and Joe for the comments!

Yes, Jo, no excuses!  If a ten thumb novice like me can do it, there's no reason anyone can't do it!

Good luck with it Joe, when you get around to doing it. It has been a fun project for me.  I'm not the fastest machinist, that's for sure, but I think I have about as much fun with it as anyone

And thanks for the comments brass shield.  Its brass, because that's what I had handy, and its there because I want to be safe! But it does make it look pretty business like, doesn't it?

Thanks everyone,
Kim

[Kim]

In the off chance that anyone is actually interested making this drill sharpening jig, I thought I'd share some of my experiences in using it on larger drill sizes - like a 1" Silver & Deming.

First off, I should disclose that these are not top quality bits - they are, however, the best set that $30 and a trip to Harbor Freight can get you!  I knew they weren't very sharp, but it wasn't till I started sharpening them that I realized how whacky they were.  Most of them were not symmetrical between the two flutes!  I had to take more material off of one side than the other to get the secondary angle's the same on each side.  The relief angle was also a curve, not a flat.  I don't know if that is a 'design feature', but after sharpening them evenly and with a more consistent geometry, they sure seem to cut better! 

Anyway, on to what I really wanted to say.  The Jig, as designed, seems to work well up to 1/2", maybe even 5/8".  But when you get much past that, you start to run into problems.  First off, the stud for the drill clamp isn't long enough, nor is the height adjuster tall enough, to allow the clamp to reach over the larger drill sizes.  Second, the drill stop isn't tall enough to make a good stop for the larger sizes.  The 1/2" (or 3/8") reduced shank just slides over the top of it. (Oddly enough, the 3/4" and 11/16" bits have 3/8" shanks, while the rest are 1/2" - go figure!)  And third, the V-channel isn't really long enough to provide support across a complete spiral (or half spiral?) for the larger sizes, which makes getting the drill bit seated uniformly a little tricky. 

So, to get around these issues, I replaced the clamp stud with a 3" piece of 10-32 all thread, and put a longer 10-32 SCHS in place of my fancy knurled height adjuster.  Not quite as easy to use, but it worked for my few large S&D bits.


And for the stop, I used a little clamp to hold a scrap of steel in place to make the drill rest taller.


These pictures show a 7/8" bit in the jig, so it's not the largest one I did.  But you get the idea.

I managed to hobble by with the stock V channel drill rest.  I had to work a little more than I should have to get them set properly, but it was doable.  At least I was able to get the bits to seat consistently - I think the larger drills sat at a slight angle, not perfectly straight.  But it was consistent.  So as long as both sides have the same angle (which they should) being off by a few degrees in the relief angle is probably not that big of a deal.  I've already shown it to be better than it was before! And much more consistent.   But as I said, if you were doing a lot of larger bits, a longer v-block would be in order.

But I'm pretty happy, regardless.  This set of 8 bits are the only ones in my collection that are larger than 1/2". But once you get under that size, I've got quite a few

Hope this was helpful (or at least interesting) to a few people.
Kim

[Kim]

Harold Hall includes plans for a little jig for sharpening small drill bits - smaller than 0.10" or so.  At least, that's the size that my version of it works with!

Again, I considered skipping this, but since I'm in shop hygiene mode I decided to go ahead and do it.  Because if I don't make it now, when will I do it? Right?

Turned out to be a fun little project.  Only took a couple of sessions for me, and for you experienced people, you could probably knock it out in a single session.

The jig is quite small, and the basic unit consists of two 1/2" lengths of 1/2" square CRS.  I used 12L14, which is very nice to work with. I've only ever found it in round and square stock. No rectangle dimensions, I don't know why.

I chose to drill it in the lathe because that way I got to try out my cool Square 5C collets.  And they worked a treat.  I drilled it for a 10-32 clearance hole.



Actually, as an instructive aside, I was going to thread this hole, but when I tried, the hole was too big for the tap.  It had something like 2% engagement on the threads.  Very bad.  I verified I'd been using the correct  number drill, which I had.  But it turns out that it was one bit I'd sharpened and apparently I didn't get the facets even between the two sides.  I'd tried to do it as a 4 facet edge (it was a #16), but with a drill that small, it was pretty touchy on the primary facet and I wasn't very close.  So, I re-ground the bit with only two facets and this was much easier to get even.  When I tried it later it worked great and came out the right size! - A good lesson for me in how important it is to get the facets symmetrical!

Anyway - back to building this jig.

I'd cut the 1/2" square stock fairly long (3") so that I had enough length to hold it vertically in my mill, as shown here, to cut the required diagonal peak in the part.  I used my newly acquired 90 degree Chamfering tool.  First I cut one side:


Then I cut the other side:


And finally, I used a 3/8" mill to bring the outside edges down to the base of the peak on both sides.


After cutting off this piece at 1/2", I started the mating half of the jig, drilling and tapping the 10-32 hole (the correct size this time!). Moving to the mill, I held the part in the same way, and cut a diagonal valley:


And the two parts fit together like this:


Taking advantage of the 10-32 threads, I used a 1" 10-32 SCHS to hold the parts together temporarily, to drill a 1/16" alignment hole:



Next I made the 10-32 stud to hold two pieces together.  Here I've just cut a 1/2" length of 10-32 threads (LOVE cutting threads on my lathe!  It's so much fun! )


And back over to the mill to drill a hole through the stud - this will allow a drill bit to pass through the stud (as you will see later).


Now another aside:
I love my Bison 5C collet chuck.  It's truly a wonderful thing - It's on my lathe 75% of the time or more.  But cranking that handle 30 times to get a collet out, and then another 30 times to put a new one in, gets old.  So I had a brilliant idea - I took a 3" piece of 5/16" square stock, stuck it in my cordless drill, and now I'm using that to change collets.  It's faster and MUCH easier.  And it's such a simple solution. So simple, in fact, that I'm sure everyone else already does this. But I'm so tickled with my little trick I wanted to share it with you.

Here's my fancy bit I made:


And here it is in action!


5/16" isn't exactly right, but its pretty close.  The tool was something like 0.325" square, so just a bit bigger than 5/16".  But its close enough and works great!

OK, once again, back to the jig.  The final piece for the small drill sharpening jig was a knurled nut to hold it all together.  Here I'm just starting to cut off the knurled nut.  It was made from a 3/8" round piece of 12L14.  I forgot to get any other progress pictures of this. But it's quite straight forward.


Here are all the parts of the jig.  Oh yeah - I also forgot to show a picture of the 1/16" alignment pin.  Its 3/4" long and I used loctite to hold it in the bottom piece.


This shows it all together with a drill bit installed:


And a shot of the business end, attempting to show how I positioned the bit:


This jig isn't used with the grinding wheel, it's used by hand, on a flat stone.  HH shows using it on a diamond stone, but this is what I had, so I gave it a go.  You rub it around on one side to sharpen that facet, then flip it 90 degrees and rub it around to sharpen the other.


It seemed to work pretty well, once I got the bit positioning figured out that is!

One final parting shot of the completed jig.


Thanks for following along with my snails paced and likely tedious build!
Kim

[fumopuc]

Hi Kim, good progress. I am still not sure if I should build this too or may be buy a Chinese clone of the famous Deckel Tool Grinder. If I remember well, I have seen one at Don's workshop  pictures.

[Kim]

Hi Achim,
I'm sure the Deckel clone would be a very nice thing to have, probably much more flexible.  But this has been a very fun project for me, and I think it probably covers my sharpening needs

Though I've discovered that some of my bits have 135 degree points, but when I'm done with them they are all 118 degrees (since that is what this fixture defaults's to).

I'm sure the Deckel supports both, and many others besides!

But I've gotten a lot of good out of it already!
Thanks,
Kim

[Kim]

The last addition to my grinding rest project is the End Mill jig.  This one has some tricky stuff (at least for me) namely, turning tapers for the collets.  But I excited to give it a try!

But I'll start with some more mundane parts. And first up is the Bearing Supports.  There are two of these; a Forward Support and a Rear Support.  They are similar, but not exactly the same.

They started as two, 1/2" wide slices of some 2"x2" 12L14.


After the straight-forward-but-not-so-trivial task of squaring up these pieces to size, I marked them up.  Here's one of them:


I started by making the large holes for the spindle bearings.  Remember, I converted these plans from metric to English measurements?  Many places I rounded to the nearest nice English unit (like material sizes, hole sizes, etc).  But, well, for some of the parts, ones I was less confident about exactly how they might interact, I did a direct conversion.  That was the case with the Spindle and collets.  So, the bearing holes are 1.181".  I figured it didn't really much matter; if I were going to turn it and measure it, I could measure any random odd number as easily as i could an odd number that just happened to match an fractional inch. It didn't seem that it really mattered much. So I left a lot of those things as direct conversions.

I was going to drill and bore the hole on the mill, but when I checked the larger drill sizes, I changed my mind:


So, I moved to the 4-jaw chuck on my lathe.  Worked a charm!  I was able to use the Silver & Deming bits up to 1".  They are newly sharpened using my recently completed sharpening jig, and they cut very nicely, if I do say so myself!


And here I'm boring it out from 1" to 1.181".


Then back over to the mill to drill all the extra holes:


And tap some of them for mounting and clamping.


Then cut a slit so that I can clamp the bearings down to keep the spindle from turning when in use.


And here's the Rear and Forward Supports.


Thanks for following,
Kim

[Kim]

It's been a couple of weeks since I posted an update, so I figured I'd catch my build log up to real time.  So, continuing work on the End Mill Sharpening Jig...

I whipped out the base.  This was a very simple 2"x3"x1/4" piece of 1018 CRS with a few countersunk holes drilled in it:


And here it is with the bearing supports mounted in place.


Next, I made the Spindle Bearings.  These were turned from a piece of 1 5/8" Cast Iron that I got from Speedy Metals.  I started by step drilling a 7/8" hole into the CI, then bored it out to the required dimension of 0.945" (this was a direct conversion from 24mm - I didn't bother to adjust the spindle & collet dimensions to English fractions.  I just left them as they fell.) I bored the hole deep enough so I could get two bearings out of it, ensuring they'd be the same size.


With the bore at the correct value, I turned down the outside to the dimension of the flange, then turned down 1/2" to the 1.181" (30mm) to fit in the Bearing Supports.


Then cut off the bearing leaving a ~1/8" flange.


After repeating the last few steps to get the 2nd bearing, I flipped them around in the 3-jaw chuck and faced off the front of the flange for each bearing.


And here they are, in the Bearing Supports.


I realized at this point that I should have waited till the bearings were complete before I cut the slit in the bearing support.  But it shouldn't be too big of a deal to set it up again and slit the bearing too.  But I'll do that later. For now it's on to the spindle!

But first.... I decided I needed to true up my tailstock.  I've been meaning to do this for some time; I've noticed that when I'm turning between centers that tailstock is noticeably off.  Not too bad mind you, but it was noticeable even to me! 

So, I took a 12" piece of 1" aluminum rod and did the procedure to true up the tail stock.  I've never done this before so it took me a few hours to get it all worked out.  For a while I was fighting a different issue, but I got that worked out, and in the end, I got to within a 1/2 a thousandths in 10" or so.  I decided to call that good enough.


With that behind me, I put a 6" piece of 1.25" diameter 12L14 between the 4-jaw and a the tail stock, and turned it down to the shape & size for the spindle.


And the Spindle Bearings fit great!


I thought I had a great idea and put the collet chuck on and used the 61/64" collet and cut off the spindle from the excess stock.

The spindle is 0.945", just 8 thou under 61/64" (which is 0.953").  It worked fine for this operation, but I started to worry about any wiggle as I was boring out the spindle for the collets.  Unlike ER collets, 5C collets seem to only tight down at the very front of the collet.  If the part doesn't fit the bore of the collet tightly, it seems like there could be some wiggling in the back of the collet which could cause deeper holes to get out of round.  Maybe this is unfounded, but it worried me.  I could feel that play in the part as I tightened it down.  when it was tight, I couldn't move it, but I kept thinking about that 8 thou of wiggle room at the back of the collet. So I switched to the 4-jaw chuck for the drilling and boring operations on the spindle.

Back in the 4-jaw, I drilled a 5/16" clearance hole in the back of the spindle (for the draw bar).  This hold had to go about 2" deep.


Then flipping it around I drilled the other half of the way through from the front!  It worked quite well!

Then I step drilled up to 11/16", just over 2" deep.


Here's what it looks like inside at this point:


Then on to the boring.  I bored it out to the required 0.709" (18mm) and made the bottom of the hole flat at 2.2"


Next was the new part for me: tapering.
I carefully set the compound slide to 5 degrees, and locked down the carriage travel.  Then used only the compound to move the boring bar in and out, and the cross slide to adjust the diameter.


After opening the hole the required amount, I had the 5 degree taper all done.  And it looked pretty good to me!  The trick will be remembering NOT to move the cross slide till after I cut the taper in all the collets I plan to make.


Here's the completed spindle:


Looking down the bore where the collets will go:


And the obligatory family shot of all parts built to date.


Which brings us up to where I left of today.

Thanks for following,
Kim

[fumopuc]

Hi Kim, great progress.  This tool build really trains a lot of usefull machinig steps.
May be I should think about that.
This tailstock position check is something I have to put on my urgent to do list too.
Never done on my current lathe before.

[Arbalest]

Nice work as usual Kim. 

[Kim]

Thanks Achim and Arbalest,

This tool build really trains a lot of usefull machinig steps.
May be I should think about that.

I'm learning a lot from doing the build. It's been very educational for me!  You are likely way past that.  But it's certainly been a fun build, even if it's not an engine!

This tailstock position check is something I have to put on my urgent to do list too.
Never done on my current lathe before.

I put it off for a long time myself (about a year and a half since I got my 'new' lathe), but I can sure tell a difference.  Things come out with the same diameter on both ends now!  And bores come out parallel, not tighter on one end and looser on the other. I clearly shouldn't have put it off so long!

Kim

[Don1966]

Kim your doing some very nice work and all those tooling will come in handy when done. I use every tool I have make and it's a joy to use them....


    
Don