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How I slowed down my Craftsman 100 drill press

Rickenbackerman

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So I picked this DP up a month or so ago and did a clean up/resto on it (left the original paint), but I knew in my mind that I really wanted to slow it down since most of my work is with metal. I went through a couple of different variations in my head on how to do it before I ordered the parts. I wanted it to be 100% bolt on with no mods required to the press, and wanted it to be as "plug and play" as possible with no welding or cutting required.

There are two ways you can go - put the bearings in the bore of the pulley or put them in the column. I chose to put them in the column. Problem is finding a slug with the proper ID and OD... then it hit me - jaw couplings! They come in various sizes with tons of bore ID's, and they have setscrews that you can turn around to lock it into the column. I got an L100 with a 1-3/8" bore. The L100 is supposed to be 2.53" OD, and when I measured the ID of my column i got 2.56", so it should have slid right in there, but for some reason, it didn't. I had to do quite a bit of grinding on it to get it to slide down in there...

Anyway, here are the parts. There's the pulley, the coupling, a 6" long 5/8" D-profile shaft, two flanged bearings and two setscrewed shaft collars. Grand total for all of this was $72.00 from Mcmaster.
IMG_20130205_195724_zpsf91b98f5.jpg


Assembly with the coupling ground down, I had to grind more on the three jaws since there is step inside the column that you want it to fit down into:
IMG_20130205_211427_zps8cf0a882.jpg


In the column. I superglued the outer race of the bottom bearing in the slug and put some fine line tape on top of the shaft to keep it from dropping down into the column whilst I tighten the setscrew (after I turned it around of course).
IMG_20130205_220835_zpsfe687435.jpg


Then you grab the shaft with a magnet and pull it up through, install the top bearing and shaft collar. Mounted!
IMG_20130205_221217_zps2b42f7ea.jpg


The original craftsman low-speed attachment had an eccentric built into it so you could tension the belt. This doesn't. No worries, that's why we have link belts! And there you have it!
IMG_20130206_000347_zps34ed55ce.jpg


Only problem is since the new pulley is a different diameter than the other two, I have to re-tension the belt every time I change speeds. I need to find a pulley like the other two and I'll be set, but at least it works for now. Oh, the bearings aren't the greatest quality, either - the upper one was spinning in the column so I superglued the outer race of that one, too.

Not to toot my own horn, but I spent a lot of time thinking about the easiest way to do this and I think my solution is a pretty dang good one. Not only that, but since the jaw couplings come in so many different sizes, I think anybody could do this regardless of their column ID.
 
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ckadams00

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Gonna have to read through this a couple more times to "get it" - seems brilliant. I have a 150 and had given up all hope of ever finding a slow speed attachment . . .gonna look into doing the same here. Only problen is the 150 has a much larger column so I may need to build an insert of some kind.
 

rsanter

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Good idea
Now can you swap the motor drive pulley and the idler pulley so you don't have to worry about retensioning

Bob
 
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Rickenbackerman

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Good idea
Now can you swap the motor drive pulley and the idler pulley so you don't have to worry about retensioning

Bob

I'd still have to re-tension if I move the motor belt, but if I left that one alone and only changed the spindle belt location, that would work! Good idea!
 

nine4gmc

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The center pulley should be offset from the center post to allow tensioning of spindle pulley.
 

evintho

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Excellent way of doing it! I did the same mod to my 150 except mine is permanent and cheap. I like how yours is removeable and done properly with bearings and such! One idea I especially like is your use of link belts. I'm gonna have to steal that idea! I couldn't find the exact sized belt for mine so I settled for one that's a little loose. I'm gonna have to check HF link belts. Great job!!
Here's my conversion..............

Homemade low speed drill press conversion
 
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Rickenbackerman

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Great idea and Execution! I WILL be stealing this! :evil:

Thanks man! I was hoping you'd see this.

How do you tension the belt between your new idler and the spindle pulley?
Jim

It's in the first post - link belt.

Excellent way of doing it! I did the same mod to my 150 except mine is permanent and cheap. I like how yours is removeable and done properly with bearings and such! One idea I especially like is your use of link belts. I'm gonna have to steal that idea! I couldn't find the exact sized belt for mine so I settled for one that's a little loose. I'm gonna have to check HF link belts. Great job!!
Here's my conversion..............

Homemade low speed drill press conversion

Yeah, I did read your thread, but I wanted to do it in a way that wouldn't permanently affect the press, and I wanted bearings...

How much of a speed change? What is your new low rpm?

Probably around 300 or so. Just guessing though, to know exactly I'd have to do a little measuring and some math.

Last night I went to swap the motor and idler pulleys to make speed adjustments possible with no belt re-tensioning, only to find out that that the motor pulley is 1/2" bore and my new idler is 5/8". So I'm on the lookout for a 5-4-3-2 step pulley with a 5/8" bore. Nothing on mcmaster, nothing on ebay except for a couple that are like 60 bucks, and I'm not dropping that much coin on a stupid pulley... I'll keep watching ebay.
 

454ragtop

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So, if you change belt positions, you add or subtract links from the belt? Seems like a royal pain inthe a**, that stuff isn't the easiest to work with.
 
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Rickenbackerman

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So, if you change belt positions, you add or subtract links from the belt? Seems like a royal pain inthe a**, that stuff isn't the easiest to work with.

For now, I'll leave the spindle belt alone and just move the motor belt up or down and then re-tension it by moving the motor back and forth. It'll work for now, but it is a PITA, that's why I'm on the lookout for a matching pulley...
 

evintho

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How much of a speed change? What is your new low rpm?

Using the chart from the Craftsman manual mine is around 175 rpm. I'd imagine Rickenbackerman's is probably about the same. For the last few months I've been cutting holes ranging from 3/4" to 2-1/2" through 1/4" steel and the speed has been perfect!

drill.jpg


drill2.jpg
 
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Rickenbackerman

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Evintho, I think the original low speed attachment used the same motor pulley as the idler pulley which is 5" dia on the big end and 1 3/4" on the small end. My idler is only 4" on the big end, that's why mine will be a little faster and so I guessetimated at 300. Also since my idler is only 4" I will have to re-tension every time I want to change speeds which is a PITA. I'm on the hunt for a proper pulley.

Could you measure your idler for me? Both diameters (big and small) and the height? Close is good enough. I need 5" tapering to 1 3/4" with a 2 1/4" overall height. Alternatively, you said you got yours from MSC, but I just looked on their site and couldn't find anything close, could you point me to it?
 

evintho

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RBman, my pulley is 5" on the big end and 2" on the small end. It's 2-1/4" tall. I've had others ask me about the pulley from MSC also. Apparently, MSC doesn't carry it anymore. I did find something relatively close on Graingers site though. It's 5" and steps down to 2". Fit's a 5/8" shaft and can be bushed down to 1/2" too. The price is pretty good. The pic shows a 3 step pulley but the description clearly lists a 4 step. They probably just used a stock photo. Hope this helps.
4-step V-belt pulley
 
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Rickenbackerman

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Well since I used a 5/8" idler shaft, that is EXACTLY what I've been looking for! Thanks man! Haven't ordered one yet, but once I get one I'll update here...

PS - my first five star rated thread, cool!
 
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Rickenbackerman

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610 rpm according to the manual. For steel, as the bit diameter goes up, the speed needs to come down. Aluminum is a bit more forgiving since it's so much softer. I'm no expert, but I reckon 610 rpm with steel is only good up to 1/4", maybe 3/8". I wanted the ability to drill as big a hole as I want.
 

kythri

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Gotcha - so, if I'm considering a Shop Fox drill press that can be slowed down to 210rpm, I should be good, yeah?
 
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Rickenbackerman

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Oooh, that's some good sh*t right there, but what about for bigger than 1/2"? I suppose you could plot and extrapolate, but that's a lotta work...
 

Outlawmws

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Google it for drilling speeds and feeds. What maters is the SFPM (Surface feet per minute) at the outer edge of the cutting tool. There are calculators for larger sizes, and for holes saws you needs that.

In general the harder the materials and the larger the diameter, the slower you go.

Softer and smaller, faster.

The same applies to woods, but wood always cuts a lot faster than any metal.
 

bluebolt

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Nice setup. I was wanting to do something similar for my 150 drill press but lucked out and found a vintage Craftsman variable speed motor 500-5000 rpm and reverse. Now I get 177 rpm to 1770 rpm without even changing the belt position.
 
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Rickenbackerman

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So found the right pulley on Eprey for a little less than what Grainger wants for one... Now I can change belt positions without having to fool with anything! You can also check out my HF 7 drawer DP/grinder stand - it's on casters so I just roll it out when I want to use the grinder. I also printed out the speed chart and posted it on the wall next to the DP... all done!

IMG_20130214_220619_zpsf3dab6db.jpg


IMG_20130214_220558_zps373cd1eb.jpg


IMG_20130214_220845_zpsc59888a9.jpg
 

evintho

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Nice job and props on the excellent use of space! You have a drill press, grinder and tool storage all in a 1' wide area! :beer: In addition, both your DP and grinder look to be vintage Craftsman! 2 thumbs up!! :thumbup::thumbup:

Now, get a real camera to take decent pics! Haha!
 
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Rickenbackerman

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Now, get a real camera to take decent pics! Haha!

I know, right?!?! :wtf: I'm too busy working on **** that I never find the time to bust out the "real" camera, the damn phone is just so handy... snap a few, upload to photobucket and off we go. I will take some decent pics if anybody is interested, but I think the crummy ones still get the point across...
 

mrbc

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I had to resurrect this thread to say great work! I have an old craftsman like this one:

http://vintagemachinery.org/photoindex/detail.aspx?ID=8979

But mine's not as pretty, however it isn't as bad off as his before pic.

I just found that I have a cap on my main post so I would be able to rig up something like Rickenbackerman. I've read evintho's post before on a different board. Rickenbackerman's is newer than the last time I was searching around for intermediate speed builds. I'd like to have the original tensioning method with an eccentric, but I like the OP's method of getting inside the column.

My other thought is to simply build a jack shaft and mount it next to the motor. I'll just have to watch the angle of the belt from a jack shaft to the spindle pulley.

Cool build!
 
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Rickenbackerman

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Thanks! I've been using this rig for a while now and I gotta say it works great. There really is ZERO need for an eccentric. Once you find the right size intermediate pulley, the belt sizes stay the same for all configurations. Though I admit I haven't tried any of the "raised motor pulley" configs listed in evintho's speed chart above.
 

Alchymist

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Having the eccentric idler is handy, as it slacks the idler to spindle belt as the motor is raised to loosen the motor to idler belt. Makes it easier to change positions on the idler-spindle belt.
 
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Rickenbackerman

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I just unplug the press and "walk" the belts from one step to the next while spinning the pulleys. Literally takes less than 30 seconds to change speeds.
 

tedsters

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I just unplug the press and "walk" the belts from one step to the next while spinning the pulleys. Literally takes less than 30 seconds to change speeds.

Good thread and good job you did on the pulley, me and a buddy were eyeing my CM 100 over and gonna build the same concept may not be original but its all new and does the same thing,

Good Job
 

McFarmer

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I slowed my Sears DP down so I could use the really big wood boring bits, I hardly ever speed it back up for wood. My solution only gave me one speed. But I kept the eccentric adjustment.

(See thread on fabricated parts)

Oh, and good job by the way.
 
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Rickenbackerman

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Thought I'd update this thread. Turns out the bearings I used were kinda crappy and were totally noisy and wore out as of a week ago.

Unfortunately I couldn't find any high load, high speed bearings with flanges, so I had to tweak my system with a couple of threaded holes and setscrews to keep the bearings in place.



I also went with a threaded hole to lock the whole thing in place instead of using the original keyway hole.



Super smooth and quiet now!
 

RSwannabe

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Thought I'd update this thread. Turns out the bearings I used were kinda crappy and were totally noisy and wore out as of a week ago.

Unfortunately I couldn't find any high load, high speed bearings with flanges, so I had to tweak my system with a couple of threaded holes and setscrews to keep the bearings in place.



I also went with a threaded hole to lock the whole thing in place instead of using the original keyway hole.



Super smooth and quiet now!

I just picked up a Model 150 DP that I'm cleaning up and want to copy your slow speed mod. What are the new bearings you used and where did you source them?

Thanks,
 
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