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MachinistBlog.com

Plans, projects and how-to's for home machinists

Harbor Freight 1×30 Belt Sander Review

This is a review of the Harbor Freight 1×30 belt sander, model #2485.  I noticed it was on sale and remembered Mikey telling me that a belt sander is a better tool for grinding lathe bits than a bench grinder.  So I checked the customer reviews for it on their web site and they were generally very good.  Then I searched for machinists who were using it to sharpen HSS metal lathe bits.  I didn’t find many, but I did learn that many wood turners were using it to sharpen their HSS blades.  It was also highly regarded by many knife makers, who were using it to both grind the shapes of their blades and sharpen them.  So I decided to take a chance and buy one.  This review is going to discuss just the sander itself.  I hope to follow it up later with another one that will talk more about how well it works for sharpening HSS lathe bits in a home machine shop.

This sander normally sells for $50 but it was on sale for $40.  I used one of HF’s easy-to-find 20%-off any single-item coupons to get it for $31.99.  I also purchased some Zirconia alumina belts for it because they were recommended by the knife makers.  Harbor Freight only carries 40 and 80 grit belts in packages of two for $2.99.  But you can easily find other vendors selling them in a much wider variety of abrasives and grits.  You can even buy a leather belt for stropping edges and cloth belts you can impregnate with polishing compounds.

Lots of problems

My sander came with a lot of problem that hadn’t been mentioned by other owners so I started wondered if mine was typical or a rare lemon.  I’d bought the last one at the store so I couldn’t exchange it for another one.  So I did more research and learned that some sanders come with lots of problems and others with few or none.  So, don’t hesitate to exchange yours if it comes with some quality control issues you can’t live with.

It was hard to put the belt cover on

It’s pretty quick and easy to change sanding belts.  The belt cover is held in place by a single knob at the top and a couple of tabs at the bottom which fit into slots.  Mine came off easily but it was difficult to put it back on because it was hanging up in a couple of spots on the frame, which seems to be made of either die-cast aluminum or zinc alloy.  I found some thick paint runs in those places which I removed with a finishing file.  I also found a small burr around the inside edge of the plastic cover which I removed with sandpaper.  It’s now much easier to put back on.

To change the belt you’ll also need to remove a small transparent plastic cover over the top wheel that is held on with a Phillips head screw.  The screw just needs to be loosened and I’m already thinking about eliminating the need for a screwdriver by making a knob or button for it.

The belt tracking couldn’t be adjusted properly

The motor and idler pulleys have an aggressive crown which helps the sanding belt stay on them.  One of the pulleys can be tilted with a knob to control the belt’s tracking.  I was pleased to find the belt would stay on over its entire range of adjustment.  But I discovered I couldn’t adjust it enough towards the motor to perfectly center it.  Adjustment in that direction was limited by a spring used to prevent vibration from turning the adjustment knob.  One of my photos will show you how I easily fixed it by adding a couple of small washers to push the adjustment lever more in the direction I needed it to go.

The motor pulley was loose Continue reading Harbor Freight 1×30 Belt Sander Review

Review: Drill Doctor 750

Drill Doctor model 750This is a review of the Drill Doctor model 750 drill bit sharpener.  Not that long ago the 750 was Drill Doctor’s top of the line model until it was replaced by the 750X, which you can buy new for about $140.  I’ve seen videos of the 750X in operation and although it looks different, I believe it works in the same way, so you may find this review useful if you are thinking about buying the newer model.

You may also find this review useful if you are considering a Drill Doctor 500X or a used model 500, which was its predecessor.  The main difference is that the 750X and 750 come with an extra chuck that allows you to sharpen bits up to .75-inches in diameter.  The 500X/500 can only sharpen drill bits up to .50-inches in diameter unless you buy the larger chuck separately as an accessory for about $40.

The 750X and 700 are also the only models that come with a carrying case, although you can buy one for the other models as an accessory.

I have heard that a good machinist should know how to sharpen a drill bit by hand, without a jig or fixture of any kind.  That’s probably true, but I am a mostly self-taught home machinist with no one who can show me how to do it.  I have tried it a few times but each attempt was a complete failure and I would have been better off continuing to use the dull bit.

I have also heard that even if you can hand grind a bit, it is hard to grind both flutes evenly so they will drill a round, exact-sized and straight hole.  Putting a split point on a drill bit is suppose to be even harder and requires a grinding wheel with a sharp, not rounded, edge.

So for me, sharpening drill bits by freehand grinding was not an option.  That left me with the following choices for dealing with my dull drill bits:

  • Buy new ones – This may be a good solution for many home machinists.  I got started about two years ago with a set of Harbor Freight drill bits that cost me less than $20 and they have worked pretty well.  I am still using them and I bought a spare set to use as replacements if they become too dull or I break one.

    I also considered buying individual high quality replacements for them as they wore out.

  • Send them out for sharpening – I’ve heard it costs between $1 and $2.50 per drill to have them professionally sharpened.  I am not going to spend that kind of money to sharpen inexpensive HF drills, although I might if I had a nice set of cobalt bits or if I used larger diameter bits (5/8-inch or bigger).
  • Buy some kind of sharpening machine or jig – I can’t afford even a used commercial quality tool grinder like a Darex.  That left either buying or making some kind of device for holding a drill at the proper angle against a grinding wheel, or buying a Drill Doctor or some other drill bit sharpener that is affordable enough for a home/hobbyist machinist.

I decided I wanted a Drill Doctor because they got great customer reviews on Amazon.com.  When someone did badmouth it, it often seemed like it might be because they hadn’t learned to use it properly by reading the instructions or watching the video that came with it.

Cost was an issue for me.  A new 750X costs about $140 and the 500X is about $30 less.  That’s a lot of money to spend just to sharpen some drill bits.  Especially if you have a limited budget and there are more important things your workshop could use.  In my case, that would be a rotary table.

So I waited patiently for more than a year for a Drill Doctor in very good or better condition to show up on Craigslist.  I finally bought a model 700 in excellent condition for $65.

Continue reading Review: Drill Doctor 750

Harbor Freight Digital Caliper Discussion

hf_digita_caliper

Toolmonger is having an interesting discussion about the quality of Harbor Freight’s inexpensive digital calipers.  They aren’t too impressed but everyone else seems to be. [Editor’s Note: They lost a lot of comments because of a hard drive failure.]

Book Review: Machine Shop Essentials

Machine Shop Essentials by Frank Marlow, PE

This is one of the best and most useful books in my library of machine shop and metalworking books. It clearly and concisely describes almost every machine shop tool and procedure, except for computer-controlled tools (CNC).  As a novice machinist, I used it constantly because I kept coming across words, tools, and procedures that I had never heard of. This was the first book about machining I bought and I highly recommend it to any beginner or intermediate machinist.  A more experienced machinist may not find it as useful since they will probably already know much of what the book teaches.

This book doesn’t just provide descriptions, it includes step-by-step instructions and useful tips for using many tools and performing many procedures. You can see for yourself by reading these excerpts from the book:

Cutting 60 degree Threads (PDF)

Sharpening Steel Lathe Toolbits

Bridgeport-style Milling Machine Advantages (PDF)

Glossary (PDF)

Machine Shop Essentials is presented in a question and answer format. It is very well organized and abundantly illustrated. It is also a fairly large (11×7 inches) book with more than 500 pages.

It is available from many sellers for $44.95 (Dec. 2007).  It is not an inexpensive book, but good books about metalworking tend to be in the $40-$60 range. In this case, I think it is a fair price. If you buy it directly from the publisher they will ship it to you via USPS Priority mail for $4.60. That’s what I did and it showed up in my mailbox two days later.

If you’re still not sure about the usefulness this book then I suggest you visit Amazon.com, where you can read more excerpts from the book and many customer reviews about it.

Random Quote

Look for someone’s strengths instead of their weaknesses.

— Fortune Cookie