Still scraping, but I also do a little lapping on my granite straight edge. Also, using the Automatic Generation of Gages to prove flatness. This installment may be found here.
I've spent most of my freetime in the last month working in the garage with a scraper in my hand.I've made some progress on the surface grinder, but I also made amistake. You can read about it here.
After spending the last yearreading about machine repair and scraping and doing LOTS of scraping, Ihave finally gotten to the point that I am going to attempt a largescraping project. The project is a 1967 DoAll D624-8 surface grinder.The first installment may be found here.
It has been a while since Iupdated anything here, but there seems to be a lot of email askingquestions on how I like the Grizzly Mill after a year of having it. SoI came out of hiding long enough to do a small piece on the mill. Youcan find it here.
Before I take a bit of abreak from the workshop to do some spring clean-up on our home, I buyan old South Bend lathe and give it some TLC. A new tool is always fun.
I finish up the Shumatech DROwith the addition of a Jenix scale and adding some ball bearings to oneof the calipers. You can take a look here.
I've been busy in theworkshop adding a digital readout to the mill. I've finished thefirst stage of the project and am quite pleased with the results. ShumaTech Dro-350 Digital ReadoutOn a follow-up note fromthe last article, I ended up contacting Grizzly agout the play in thespindle. I spoke to one of the technical reps and explained thesituation. Rather than being without a working mill for however long ittook for them to get parts, I suggested that I would send them adrawing with all of the measurements of both the spindle's splinedshaft and the spindle drive. I sent it off a day later with a requestfor a spindle drive with the smallest measurements that they could findand if it was too tight, I would file it to fit. About a week and ahalf later I received a new spindle drive. Unfortunately, it is notmuch better than the one I have. It is one thousandth, maybe 15ten-thousandths tighter than the current drive. Better, yes. Right, no.
So, it was out to the webagain to do more research. I had been thinking that it would bepossible with some of the "pourable" or "castable" metal containingplastics, to build up a shim to remove the excess play between thesplined shaft and drive. Well, there's a company named Devitt Machinerywith a product named Moglicethat repairs lathe and mill ways in all manner of sizes. This stuff isa godsend for repairing large machines where the ways are measured infeet rather than a hobby sized machine. The question I still have iswhether it can take the constant "hammering" that this drive issubjected to when the mill is cutting an uneven surface. It would seemthat constant compression that a lathe way would see is much differentthan going from zero force to a ton or more of compression 1000 times aminute or more. It is certainly something to learn more about, though.
Anyway, I have to giveGrizzly an "A" for effort, promptness, and being courteous, but a "C"on execution. Maybe this is just one of those things that if I want itright, i'll just have to do it myself.
I found another littleannoyance with the mill. This one got a temporary fix that isworking out well, for the time being. SpindleNoises
There's a new piece on moving the mill into the workshop.
Well, the delivery was a bit late, but itdid arrive on Thursday. One Grizzly G3103 knee mill. The mill is a Chinese made piece that appearsto be a clone of the Clausing 8520/8530 series and is one of thenicer Chinese examples of this style of mill.
The crated G3103 is about 950 poundsshipping weight, but you can drop about 100 pounds for the crate. As industrial mills go, this is a light-weight. As a mill for thehobby machinist, it is pretty substantial. I will be strippingthe mill down to pieces in order to move it into my walk-outbasement. It is just too heavy to move as a single piece into thebasement. It will also allow me to clean all of theoil and gunk that somewhat protected it from rusting on its journeyfrom Chinato Virginia. I will also be making sure that everything is set upcorrectly so that it will be as accurate as possible.
I have been wanting to get a millfor years, no, decades, but something else always seemed to come upthat I needed more. When I finally decided to make the purchase, Ispent about 2months of non-stop milling machine research before I finally spent thedollars on the G3103.
I started out with the intention ofbuying aused Bridgeport "J" head, Clausing, or any the better known American/ import standards. However, as I seriously began to look, the formermechanic and sometimesmachinist side of me took over. As a former Mazda mechanic, Iknewthose cars as well as most Mazda mechanics up until the time I stoppedworking on them every day. After that time, I can say I generallyknow the cars, but I wouldn't call myself a Mazda mechanic anymore. For a while I specialized in other imports, but never knewthem as well as the guy who spent 5 or 6 days a week living andbreathing that brand. So I started thinking about mills in thesame context. What did I know about mills? I figured thatthis probably summed it up well: "I know enough to not foolmyself into thinking that I could choose an old mill and not wind upwith junk." Or maybe I don't know enough to choose a mill thatwould "just" take me many moons to get decent accuracy outof.
Yes, I could get lucky and find one thatwas 20 years old, but not used much. If you read the bulletinboards atthe Home Shop Machinist and a half dozen other sites where machinistshang out, you'll find that there's always someone who just got anincredible deal on a "barely used" 25 year old piece of industrialequipment, but after watching Ebay for the last 2 months, I'd have tosay that the norm is more like "well used," than "barely used" for theolder Bridgeports. The "barely used" - or even "well cared for"industrial mills in the price range that I allowed myself, (around$2200), do exist, but you'd need to know your mills well to findthem.
Another challenge with the "old iron", isthe priceof shipping. The Grizzly would cost me about $160 to get it fromPennsylvania to Virginia, and another $75 to get the shipping companyto bring a lift gate and pallet truck (pallet mover) in order to beable to lower the crate from the tractor trailer to the street and thenfrom the street to the garage. I'm told that Grizzly gets afavorable rate because of the volume of shipping that they do. Onthe other hand, since the Bridgeports are about twice the weight of theGrizzly, the shipping is substantially more. You also usually gethit with a crating charge of $100 to $300, so if the mill you purchasedon Ebay turns out to be less than what you thought it would be and youcan actually return it for a refund, you are going to be out asubstantial amount in shipping and handling. Perhaps if I livedin an industrial center where there were more mills (or for that matter- ANY mills) listed in the want ads and I could visit each one andcheck it over, I might have been able to find a good used piece.
Anyway, enough of why I didn't go with a used mill. When Idecided to go with a new mill, there were a few that were in therunning and a few that I read about that I never seriouslyconsidered. First to get thrown out of contention were the roundcolumn "mill/drills." On the plus side, they usually have apretty fair amount of Z axis travel (up and down movement). However, because of the round column, when you change tools - like whenstarting with a small diameter (and length) drill bit and progressivelygoing to larger and larger sizes, the head must be moved - and theround column makes it hard to get back to the exact location that youstarted in. There are a couple of alternatives that avoid thisproblem. One, getting a mill/drill with a rectangular column,which allows you to keep the head frommoving. Two, getting a mill with a "knee." The knee allowsthe table to move up and down and the head doesn't have to move atall. You can move the head up and down a few inches (depending on themodel), but it is usually more accurate to move the knee. Thenext type of mill that I had to pass on was the combination mill andlathe. While I do want a lathe, the combination mill and lathe inthe lower price ranges just don't have the accuracy that Iwanted. It is possible to get a combination mill and lathe withgood accuracy, but the ones with the great specs start at about 5 timesthe price I wanted to pay.
Of the mills I didn't consider were thesmall table models, like theSherline and Taig. These are pretty neat little mills if you areworking with small parts, but I wanted to be able to work with largerstock. If everything else is equal, the mill with more mass willdo the better job as there is less flex.
So I finally got to the point that I had chosen a general style of mill- a knee mill, and the size - 6" by 26" - which is the tablesize. I decided on a Chinese mill because right now it is thebest "bang for the buck." Which narrowed it down to the GrizzlyG3102 or G3103, the same mills by Harbor Freight, or the 3004-0095 fromWholesale Tools. I think that I read pretty much everything onthe net regarding all of these mills, including a pretty helpful Yahoogroup called 6X26 milling machines. I happen to have a HarborFreight fairly close to my house and took a drive out there with hopesof seeing their model, but they only had a couple mill/drills. The quality of the two mills I saw were pretty bad. The gearedversion of the rectangular column mill/drill was sitting in a puddle ofoil from the gearbox and there was so much sand under the paint that itlooked like they had sprayed it in a sandstorm. Whoever haduncrated it hadn't bothered to wipe it down to remove the oil to keepit from rusting in transit from China, but under the oil wasrust! I can't explain that one.
I spent some time trying to decide between the Wholesale Tools versionand theGrizzly. The WT is less expensive, but the Grizzly had greatreviews of their customer service. In the end, I decided to spendthe extramoney for the Grizzly. and I now have the mill!
That's pretty good. I have condensed a couple months of studying,searching for information, and learning into a few paragraphs. Suffice it to say that I now feel that I am not a complete rank amateur/ newbie. I am a more knowledgeable rank amateur / newbie! However, this will change a little more for the better as I strip andreassemble the mill in order to move it to the basement workshop. I have been through the process a few times in my mind and have a stackof notes from articles I have read on things to look for, things todouble-check, and a lot of notes on how to scrape and lap the ways (theways are a thin strip of metal that is used to set the clearances ofeach axis).
Next up, stripping the mill down so I can move it.
Comingsoon!The newmill is on its way... more to come.
