Author Topic: Basic Tool Sharpening Jig  (Read 7364 times)

Offline propforward

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Basic Tool Sharpening Jig
« on: October 14, 2018, 10:08:06 PM »
I recently learned that my free hand ground cutting tools are simply not good enough. I found myself having a terrible time turning mild steel, which shouldn't be that hard, surely? After a lot of regrinding, I did satisfy myself that a lot of the problems I was having were from the quality of the cutting tools I had ground.

I've been meaning to make Harold Halls basic tool grinding table for ages, so I finally got going on it.

I made a few changes to the design - nothing extraordinary, but I don't want to have to get on the thing with a bunch of hand tools to set it up each time, so it's going to be held steady with a magnetic base (10 dollars from Grizzly), and changing out a few of the screws for hand knobs.

Looks sort of like this, although the model isn't quite finished.



I beefed up some parts as well.

This is likely a little more complicated than it really needs to be, but it does mean that it can be set precisely, and furthermore gives me a lot of practice at various techniques, such as turning threads, slotting, milling to size, angled cuts on the mill, positioning holes.......all good general purpose stuff.

First few parts - some purchased, some made. Mixed results on my first set of threads. Like I say - having some difficulties with mild steel at the moment, but making progress. I ended up having to run a die down my first turned threads because they were rough. But at least the diameters and pitches were correct.



I'm making the table out of 5/16" steel, rather than 6mm, just for a bit of extra material for the tapped holes.

I started out by spotting all the hole positions - positioned using the hand wheel dials. I counted to ten a lot today.



Then blind drilled



For the slot, needed to guide a block on a leadscrew, I drilled 1/4" holes at each end of the slot, and then milled the slot to size using a 3/16" end mill, rather than just try and mill the slot with a 1/4" end mill. I figured this would give me better control over the slot width, by milling one side, then the other. It worked - I was less than 0.001" off on the width. Somewhat pleased about that.





I did the slot in 3 passes, taking the slot down about 1/8" each time. Although it really didn't strain anything, so I could possibly have done this in 2 passes.





Finished article, before deburring and tapping



Next up - some bearing blocks, to hold the various leadscrews. Pretty simple - 1" long brass blocks, with holes to attach to the table, and a cross hole to hold the leadscrews.

I was lamenting not having a work stop yet, since I have to make 3 of these, then realised I do in fact have a simple one, which came with my vise, so these were knocked out in short order.









I actually put the table back in the mill, and put a chamfer on the slot with a countersink tool, to clean it up. Then after deburring everything, put these few parts together.





Pleased to see that all my holes lined up so far - all done by positioning with hand wheels, so while my machined finishes aren't perfect yet, I can at least count, so that must amount to something.

Next up, the sliding block and lead screw, and fence. That will be for next weekend though, too much happening this week - won't get in the shop for a bit.
« Last Edit: October 14, 2018, 10:12:34 PM by propforward »
Stuart

Forging ahead regardless.

Online Kim

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Re: Basic Tool Sharpening Jig
« Reply #1 on: October 15, 2018, 05:44:18 AM »
Looks like a good start on a great tool!
l'll be interested to see how your modifications work out.   Seems like they will be a real help!
Kim

Offline Ye-Ole Steam Dude

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Re: Basic Tool Sharpening Jig
« Reply #2 on: October 15, 2018, 09:54:15 AM »
Hello Stuart,

I am also interested and will be following your progress.

Have a great day,
Thomas
Thomas

Offline propforward

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Re: Basic Tool Sharpening Jig
« Reply #3 on: December 08, 2019, 02:54:46 PM »
I'm not exactly rocketing along with this. In fact, the forum gives me a dire warning that this topic has not been posted in for over 120 days. Do I really want to post here?

Well yes.

So I don't have good in progress pictures. This is where things stand today.



The good is that tapped holes align with mating parts.

The dovetail slides are OK. A bit rough. I made a single set up, and made sure I machined the slider bar and guides in the same set up, so that even if the angle is not precise, the parts should mate OK, and they do. The finish on the angled sides is not great, so I need to work on technique, but for this a light clean up will have things working well. The slider does fit between the rails with no play, and slides so I suppose that's a win.

The screw that drives the slider binds in the brass block - the hole is not concentric with the tapped hole in the slider. I'll be working on that today. Either flip the brass block over - or, if that doesn't work, I'll take a couple of thou off one side of the block. I'm disappointed to have these fit issues, but I can make them work and recover so that I can move on. It makes me wonder how I'll properly finish a set of engine castings if I can't get these simple things right, but maybe being honest and identifying these issues is key to working out good practices and improving.

Some of these issues had me putting this project aside and dealing with other things, but a visit to my Dads workshop recently, and seeing his lovely engines has me inspired to start again.

Today I find myself able to get to the shed and pick this project up again, so I'm looking forward to that.
Stuart

Forging ahead regardless.

Online Kim

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Re: Basic Tool Sharpening Jig
« Reply #4 on: December 08, 2019, 03:59:49 PM »
....I'm disappointed to have these fit issues, but I can make them work and recover so that I can move on. It makes me wonder how I'll properly finish a set of engine castings if I can't get these simple things right, but maybe being honest and identifying these issues is key to working out good practices and improving.

Stuart, I think you're right on here!  I can't speak for everyone but I know I have these kinds of fit issues all the time.  But as you say, practice helps you improve - in multiple ways. One, of course, is that you get more accurate in your work overtime.  But another is you learn what things matter and what don't.  And you also get a bigger bag of tricks on how to recover from these inevitable fit issues.

Keep with it and don't lose heart! (easier said than done, I know!)  Your tool sharpening jig is looking good!  Keep with it and you'll have it done :)
Kim
 

Offline scc

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Re: Basic Tool Sharpening Jig
« Reply #5 on: December 08, 2019, 06:42:52 PM »
I'm with Kim there Stuart,     :popcorn: :popcorn:    Terry

Offline Roger B

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Re: Basic Tool Sharpening Jig
« Reply #6 on: December 08, 2019, 06:52:44 PM »
This tool is on my list as well but I side-tracked it by using replaceable insert tooling. I still need to do it for specials  ::)
Best regards

Roger

Offline propforward

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Re: Basic Tool Sharpening Jig
« Reply #7 on: December 08, 2019, 09:16:21 PM »
Thanks all.

I made a bit of progress today. I discovered that the problem with the binding slider was less misalignment of holes, and more to do with the thread in the slider not being square. I can certainly improve that, and make a tap holder for the mill to hold taps straight when starting threads - or something along those lines. For this fixture I adjusted the brass block to make everything work.

The next problem I ran in to was when I started turning the longer lead screw down, I couldn't get everything clear of the tool - I mean I was using the tailstock with a dead center to support the end of the shaft I was turning, but no matter how I adjusted the lathe cross slides, the toolpost kept running in to the tailstock, and I couldn't machine the shaft. So that's my next problem to figure out. Maybe I make some kind of extender for the tailstock, or make a small follow rest. I tried the follow rest that came with the lathe - but similar problem - the lathe cross slide runs into the follow rest before the tool meets the work piece. Frustrating! But I want to work through this, because I'm going to need to turn more long, thin shafts, so I might as well make a good set up now.

Probably just a matter of using my collet chuck instead of the 3 jaw to get clearance there, and rotate the compound slide around some more - possibly allow a length of sacrificial material at the tail stock end  of the part. Worst case I'll have to put a different tool post on, with a holder that will allow mt to extend the tool away from the post so everything clears. That's probably the trick. I'll try some different set ups, I think I have what I need to make it work.
« Last Edit: December 08, 2019, 10:01:59 PM by propforward »
Stuart

Forging ahead regardless.

Offline propforward

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Re: Basic Tool Sharpening Jig
« Reply #8 on: December 08, 2019, 11:03:10 PM »
Had a facepalm moment.

 :facepalm:

I managed a small diameter long shaft, supported both ends, when I made the connecting rod on my Number #14 engine.



I just need to grind a new tool to allow me to angle the toolpost this way, but get a knife edge in to cut a square face as I turn down.

Duh.

In fairness, I've had a bad cold this weekend, and I'm not firing on all cylinders. Glad I take pictures of things though, very helpful to look back sometimes.

 :facepalm2:
Stuart

Forging ahead regardless.

Offline propforward

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Re: Basic Tool Sharpening Jig
« Reply #9 on: December 23, 2019, 12:09:24 AM »
What a trial I've been causing myself. I have been having a devil of a time with mild steel. I have been having a really tough time getting any sort of finish worth speaking of, and it's really been frustrating me. I've been trying to make the long lead screw used for adjusting the fence position. A simple enough part, but whenever I turned it, the surface ended up ragged and rough.

In the end I went back to my various machining text books and of course the intertubez, and studied HSS tool bit grinding and set up. Last weekend I spent a good amount of time hand grinding a new cutting tool, using a 120 grit grinding wheel on my bench grinder. I had to do all this free hand because I haven't made my grinding jig yet. In any case, I took my freshly ground tool and honed it on a stone, and was pleased that I made significant progress, and started to make cuts with a little more finess.

Buoyed by that bit of intermediate success, I actually pulled the trigger on some A.J.Warner HSS insert tooling, since I had recently read good things about this product.

The new cutting tools came yesterday, so today I hurried back to the shed, with no small sense of excitement brewing.

Time for some pictures - pictures usually mean I have made some progress. You'll note the lack of pics from the rubbish turnings above.

Just a basic 3/8" set for general purpose turning.



For comparison, here are 3 tools.



The right most tool is the oldest hand ground one I have, and was not producing good cuts at all on mild steel. The middle tool is one I ground last weekend, and I actually had some good results with it. Then on the left is the Warner tool.

It took me some time to get set up, but I did start to have more success, as you can see here.



The really rough looking part of the diameter was made with the first tool in my above picture. Kind of a comparison cut. You can see the superior finish being achieved with the Warner tool. Actually I got a similar finish with my middle hand ground tool to this.





Up close though - still not that good.





I decided that since I was going to thread this part, I could live with this finish - for now. But I'm still peevish about it.

Unfortunately...............



 :ShakeHead:    :Mad:      :cussing:     :facepalm2:

Start again. Main component got bent in the fracas.

Before starting again though, I spent some time trying to dial in cutter set up and surface finish - because really, this surface issue on mild steel is really starting to bug me.

Just to reassure myself, I did a quick cut on a piece of aluminium, just to reassure myself that everything hasn't gone completely to pot.





The surface finish gets exaggerated in the photo's, but the fingernail test said this was a very nice finish.

I spent a good hour and a half performing more test cuts on pieces of mild steel, and eventually did make some progress.

These are just some turned diameters to examine finish.



The smaller diameter on the left is the best I achieved so far, and I did feel it was close to acceptable, so I re started making my lead screw.



This is more like it.



I went ahead and turned the screw part with a support on the tailstock end (should have machined the long diameter first, but whatever).



It worked out overall, but the finish on the long part of the lead screw is not very good.



 I'm wondering if this is just chatter from it being a long part with small diameter. My lathe is definitely suffering from some vibration, and maybe that plays in on the longer, more slender parts. I do feel I need to make the base a lot more rigid, and check head stock bearings and so on, probably belt tension as well.

I feel very much like a bungling amateur, but even so I think I'm making progress, albeit slow. I was pleased that my own hand ground tools performed well. I like the Warner tools, but I still want to be able to properly grind my own tools, especially for being able to make good boring tools and other items.

I'm determined to finish this grinding table before I make any more engine parts. I need the practice. I keep looking at steam tractor casting sets - not pulling the trigger on any of those though, until some proper progress gets made, and a few less silly mistakes!

Thanks for your attention. I appreciate comments and feedback, I find it very helpful.
« Last Edit: December 23, 2019, 12:13:08 AM by propforward »
Stuart

Forging ahead regardless.

Offline 10KPete

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Re: Basic Tool Sharpening Jig
« Reply #10 on: December 23, 2019, 01:43:14 AM »
Those later finishes look very good for mild steel. They could use a little improvement but a quick pass with a fine file and some abrasive paper will make a fast improvement from where they are.

I have found, with my South Bend 10K, that I get the best finishes on MS with HSS, with finely finished tools. Hone the edges just as you would the fine edge of a good knife. Flat stone the front (side relief), end (front relief), and top (rake). Make sure the edges all come together at the edge with the honing, nice and shiney. Then carefully stone a small radius ( about .02" rad. or a bit more) on the end corner keeping the angles.

Then run the tool at about 180 ft. per second with some cutting oil. The oil is to stop chip build up on the top of the tool edge. That build up wreaks havoc with finishes and sizes. Check the tool often to assure no build up.

Have fun!

Pete
Craftsman, Tinkerer, Curious Person.
Retired, finally!
SB 10K lathe, Benchmaster mill. And stuff.

Online Kim

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Re: Basic Tool Sharpening Jig
« Reply #11 on: December 23, 2019, 01:49:32 AM »
Hi Stuart,
I'm no expert, but those are the kinds of finishes I get on 1018 steel.  I get better finishes on 12L14.  But as Pete said, a run over with a file and some sandpaper cleans it up nicely.

Kim

Offline propforward

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Re: Basic Tool Sharpening Jig
« Reply #12 on: December 23, 2019, 02:30:24 PM »
Thanks fellas for your input and encouragement! It really helps, and I appreciate the advice. I will add those techniques when I go and machine the next piece of mild steel.

I have machined 12L14 before - got a lovely finish on it, which is the beauty of that free cutting steel I suppose. That may have thrown me off, and created unreasonable expectations when trying a more difficult alloy, but I certainly don't mind giving it my best and not giving up on the 1018. I have learned a lot as a result. Frustration along the way - sure. But a net gain overall.
Stuart

Forging ahead regardless.

Offline crueby

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Re: Basic Tool Sharpening Jig
« Reply #13 on: December 23, 2019, 02:40:58 PM »
The 303 stainless cuts a lot like the 12L14 but doesn't rust so quick, I use it for most parts now.

Offline propforward

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Re: Basic Tool Sharpening Jig
« Reply #14 on: December 23, 2019, 05:09:35 PM »
Thanks Crueby. We make a lot of stainless weldments where I work - great big complex things - anyway I score a few pieces of 304 and 316 here and there. To be honest, I didn't have too much trouble machining 304, although it does take me a long time! I had expected 304 to be a lot more difficult to machine than 1018, but the reverse was true. I'd like to try some 303 now, just for comparison sake. Plus - good point on the rust factor.
Stuart

Forging ahead regardless.

 

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