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Troyaero
02-10-2005, 03:20 PM
I am new to the forum and new to machining. I have several nice machines which I have yet to really start using. They include two lathes and two shapers. I am interested in learning how to sharpen tool bits and find that according to who I talk to there seems to be a number of ways to get the job done. Question I have at this point is what are the merits of having an actual tool bit cutter/grinder such as the model shown in Harbor Freight like: http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=45707

versus the more traditional grinder:

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=46727

The universal grinder is quite expensive and if you go for a non-chinese version the price easily soars. How do you cut exact angles including reliefs without one of the more expensive versions. They seem to have the tool holders that can be "dialed in" were as the simpler grinders will need some additional mechanical help to find and hold the bit properly not to mention the proper grinder wheel added. I was looking for a store bought tool bit holder that I could add to my surface grinder that I have which receives no use. Any comments?

Alistair Hosie
02-10-2005, 04:31 PM
looks good

[This message has been edited by Alistair Hosie (edited 02-10-2005).]

Zep
02-10-2005, 05:22 PM
first unit is more of a cutter (milling), and drill bit sharpener. the second unit is for hand grinding carbides and hss toolbits for lathe or shaper. from your post the second would be of much more use to you. Most experienced machinists grind freehand tools using approximations of angles, the second unit you can set to assist in this, different matl's and clearance issues (boring, int'l threading etc.) will force you to modify tools to cut effectively. A little trial and error and you will quickly learn what cuts and what doesnt. The machinery handbook gives detail info with diagrams about basic tool grinding and upon seeing it you will see how the toolbit relates to the grinder. It is not neccesary to secure down the toolbit in most cases as by laying the tool on the rest and moving into the stone the downward force of the wheel holds it done while your hands carefully apply the forward pressure to the wheel. As always Safety first, good luck

[This message has been edited by Zep (edited 02-10-2005).]

[This message has been edited by Zep (edited 02-10-2005).]

Yankee1
02-10-2005, 08:41 PM
Hello
I have the second one, it comes with two green wheels for carbide tools. I like it very much and feel that it is a great value.
I bought mine on sale last month for 119.00
at Harbor Freight in Medford Oregon.

flatlander
02-11-2005, 10:15 AM
I have one of the HF carbide grinders on order, and am trying to decide which aluminum oxide wheels I'll want for it, as I'm told the green wheels aren't well-suited for fast material removal when grinding new tools from blanks. I paid a quick visit to Norton's website and it seems that one of their type 32AA 46grit wheels would work for rough grinding, but what do I need for putting a finer finish on a tool?

kap pullen
02-11-2005, 11:05 AM
Troyaero,

I started, and still grind most tools by hand.

That's the way my teacher in high school showed me starting in 1967.

He made us first grind then in keystock for his approval, than in hss.

We had to hand feed the lathes for the first couple weeks.

That tought us the effects of varius rakes, and lead angles had on the cutting action.

That saved many jam ups on the machinery too.

My teacher was John R Walker, author of the book Machining Fundamentals, that is still avalible.

He presented each of us with the book signed upon completion of the course.

Thank you Mr Walker.

Kap Pullen

madman
02-11-2005, 11:05 AM
Where in Canada do you get one. Ever since I bought a van sant bender for 260 bucks and it ended up costing 1500 I wont order ANYTHING from the states. Its like a third world country getting things through customs brokerage fees ect. Thanx

precisionworks
02-11-2005, 09:36 PM
Here's an endmill sharpening fixture, used with a surface grinder:

http://www.penntoolco.com/catalog/products/products.cfm?categoryID=4507

Sharpens from 3/8" to 1", with 2,3,4,6 or 8 flutes. Gives professional results.

Use a Drill Doctor 750 for everything else.

------------------
Barry Milton

BillH
02-11-2005, 09:55 PM
Flatlander, the O/A wheels that j&L sell for that grinder, (type 2) are listed as 46k grit. I thought they were roughing wheels, but after using them, they give me a great finish.

vinito
02-11-2005, 10:25 PM
I spent a bunch of time in front of an Agathon tool grinder that works similar to the HF (first link). Agathons are a very expensive version (larger too) and they work great. We had 150 CNC swiss lathes and keeping the tools sharp for them kept 2 grinders spinning all day. The lathes all had carbide cutters and the grinders had diamond wheels. In this setting, the grinders made a lot of sense - the tooling was all pretty small so high-precision grinding was tricky but necessary (some of the boring bars were for .020" bores!). All the tools were ground nearly identical so hassle during tool changes was kept to a minimum. In the home shop, you can grind pretty well by hand, but those tool grinders sure make it easy.
The HF pictured looks like it takes round shank tools (drills, small boring bars, etc.). The agathons had that, but the bulk of our grinding was OD tools using this tool holder on the grinder:

http://img.photobucket.com/albums/v110/mikeyphoto/agl2.jpg

It does work very well and I'd take one if they offered (even the HF version). Of course the HF won't be as nicely made, but the concept is the same. If I had the money, I'd probably spend it on something else I needed more - there's lots of things higher on my list. If you can really use one a lot, or want/need to grind quick & accurate cutters, it might be worth it. I'd like to see one up close and get some fingerprints on it. Kinda neat for 1/10th the cost (or less) of the Agathon, at least as long as it's reasonable quality.
Gorton made one similar to this too:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=45022&item=3871781564&rd=1
These all look similar to the popular make-it-yourself Quorn tool and cutter grinder. Google "quorn grinder" and check that out too. There's a Yahoo group (of course) for those guys. You might adapt some of the Quorn ideas to your surface grinder with a cup wheel or something.

$.02

[This message has been edited by vinito (edited 02-11-2005).]

ibewgypsie
02-11-2005, 10:53 PM
http://members.aol.com/lughaid/toolbit.jpg
http://users.aol.com/lughaid/cuttools.jpg
http://members.aol.com/lughaid/index.htm posted here..

Madman..
Mine sold on ebay. Bender, 1" shoe, mount, degree wheel sold for $400. I got a pretty good return on my investment. Seem to remember having about $600 in it.

Canada? I could've checked the "gift box too". If we can get away with it, I don't mind relaying items.

Have you build a decent frame jig yet? a piece of 12" channel scribed centerline down the middle is the best. All jigs should be pinned and bolted to return each time.
(my new bender has a cylinder) I scanned the Model 3 into a Gcode drill file and cloned it. I kept the 1" square shoe. It ain't a "real one" but the pins drop through.

David

happy02
02-11-2005, 11:16 PM
I wonder if the Diamond tool holder would fit your bill. To sharpen the bits you'd need the second grinder. The HSS bits are simple to sharpen and from all accounts cut well. It will work for the Lathe but not for the Shaper though. For that you will have to hand grind or build jigs for the Surface Grinder.
There has been some nifty grinding jigs for grinding Lathe threading bits on a Surface Grinder in this forum lately but you have to make the jigs.

flatlander
02-12-2005, 01:02 AM
Thanks, Bill. I'll try a 46K and see how I get along. Norton's site listed grits of 46, 60, & 80.

Troyaero
02-14-2005, 01:50 PM
Well I will look into what has been posted which I can make for my surface grinder. I have one of the older Delta/Rockwell surface grinders. That particular model could be had in several verisons back in its day. One was fitted specifically to be a tool bit grinder. The Rockwell web site has the orginal manual for the surface grinder version but not the tool bit version. I have seen one set up to be a tool grinder once in a machine shop when I went to look at another tool grinder that was for sale. The for sale machine was only $100 but it was huge. I had no room for it. I think in the meantime I will look into the simple Harbor Freight grinder that most here have commented on. The price is right especially if I can get one on sale. I suppose though I can do the same thing with my surface grinder if I have the correct wheels and also set up a table that will allow me to hold the bit at various angles. I keep going back to the surface grinder since I have not had a reason to use it as of yet and it just sits.

JCHannum
02-16-2005, 02:35 PM
I just saw this one; http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=45022&item=3875123287&rd=1

Price is reasonable right now.

mattc
02-16-2005, 03:48 PM
has anyone used a belt sander for sharpening bits and if so how did it work out? any thoughts?

Matt in AK

jburstein
02-16-2005, 06:41 PM
The fellow I worked for this summer used a large (LARGE) disk sander to do the roughing of bits, then used a fine grinding wheel to do the final sharpening. Seemed to work fine for him.

-Justin

Spin Doctor
02-16-2005, 07:14 PM
Disc and belt sanders will work just fine as long as you can keep the temperature under control

.RC.
02-16-2005, 08:59 PM
I use a multitool to sharpen my bits and drills and stuff...It is just a belt sander attachment for the grinder...While it would be dearer to use instead of a grinding wheel i can change grits in 5 seconds so i can rough with a 100 grit belt then finish with a 400 belt....I find it heaps better than a plain bench grinder....

http://www.ausmultitool.com/default.asp

Thrud
02-17-2005, 04:00 AM
Matt
I have a 1"x42" that does a loverly job with 1000x SiC mylar belts - gives the bits a mirror finsh with little or no need to hone them.

That works for me, but I also have a Beaver that I scored for $20 (CDN$) at an auction - has double row locked bearings for diamond wheels - runs forever after you turn it off. A great grinder like one of these old babies makes grinding any tool easy and quick. The baldo Carbide grinders are nice machines, but really overpriced. I don't know if the HF carbide grinder is useable or not - we don't have HF here...