Penncraft Drill Press (Delta Homecraft) Slow Speed Pulley Build

McBrownie · Dec 7, 2015

First of all, I would like to thank fellow GJ'r JZiggy for his input into this solution. He makes intermediate pulleys for Craftsman Drill Presses which can be found here:
http://www.garagejournal.com/forum/showpost.php?p=5184743&postcount=54

Here is my 1960's Penncraft Drill press which was made for J.C. Penneys by Delta. It's a Homecraft Model 11-100. I picked this up a month or so ago and have really enjoyed having it in the shop.

Before a clean and lube:
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And after:
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One problem, though. The slowest it will go, according to the manuals on vintagemachinery.org, is 700 RPM. The largest pulley is 5 1/8" and the smallest is 2 1/8" for a speed reduction of .415. With a 1725 RPM motor, this steps it down to 716 RPM. By adding an intermediate pulley of the same size, I should be able to get that reduction again, for a final RPM of 297 if I did the math correctly.

The biggest challenge of getting a pulley mounted in the column is the lack of space on this model. I looked at doing a jackshaft mounted off to the side, but decided that I didn't want an exposed belt and pulley either by the quill handle or the on/off switch. And, I wanted a challenge.

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McBrownie · Dec 7, 2015

The column on the Penncraft is on the small side with a 1 7/8" O.D. and an I.D. of a little over 1 9/16". I don't have a lathe (I wish I had a lathe), so I needed to find a way to mount something in the column. More accurate measuring showed that I had 1.570-1.575" for the I.D. Digging around in the shop, I found some old 6203 bearings left over from a Craftsman Block grinder rebuild (or two). 6203's have a 40mm O.D. which is just about 1.575". Perfect!

My next thought was that I didn't want the pulley riding on bronze bushings. For the amount of use it is going to see, bronze bushings would be fine, but what is wrong with a little overkill now and then? Since I don't have access to a machine shop, I thought that a pillow block would be the easiet way to get a bearing mounted. I looked at different configurations, and ended up with an AMI UCFB202-10 5/8 Flange Bearing. It has three mounting holes, which seemed like enough. I also had a scrap piece of 1/2" aluminum which was just big enough to work as a mounting plate, even though it had a few holes in it already.

I scribed around pillow block, drilled and tapped three 5/16-18 threaded holes for the pillow block and a 1/2-13 threaded hole offset from the center line of the bearing to bolt up the column bearings. This will let the pillow block swing for belt adjustment.
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Along with a lathe, I also wish I had a band saw. Cutting out the profile with a scroll saw was brutal. Lots of WD40 kept the blade moving and after a while, it was done. By the way, my Wilton 9300 did a fantastic job of holding this piece when there wasn't much to grab onto. I was using smooth jaws too.

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After a little time with the Multitool grinder, and it looks good. By the way, since I'm doing overkill, might as well use Grade 8 hardware too. I could probably tow a car with this.
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Here it is with a stack of 6203 bearings held in a place with a 1/2-13 bolt, a 5/8" sleeve to match the I.D. of the bearings, and a couple of washers.
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McBrownie · Dec 7, 2015

Now to get to work on the column and yet another time that I wish had a lathe. But, since I don't, I needed to find a way to clean up the I.D. and get it to a decent interference fit for the 6203 bearings. This was a seam welded pipe and had a ridge running down one side.
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Enter the Dremel. Dremels are perplexing tools to me. Sometimes they fail miserably and other times you wonder how you ever lived without one. This was one of the good experiences. It plowed through the weld and cleaned up the I.D. in no time. A little adjusting and I had a good solid fit.
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Now is where getting enough movement for belt adjustment is going to be a challenge. I ground a relief in the mounting plate to give me just under an inch of "swing".

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And here is a mock up with a temporary shaft and a matching DP260 pulley that cost me almost as much as the whole drill press. That is the way it goes. I'm waiting for a ground 5/8" drill rod to show up.
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Now, for the belts. Standard v-belts or link belts? I would like to hear some opinions at this point. Thanks for reading!

JZiggy · Dec 7, 2015

McBrownie -- WOW. I am super impressed with how that turned out. Took some real MacGyver'ing too!

I will be interested to hear how the auto-tensioning works out with the bearings mounted in the column.

Regarding belts, I like the ContiTech ones that are about $5 on Amazon - LINK

I found that link belts actually give you less gear reduction since they are so think. The neutral axis of the belt is shifted further out from the center of rotation. So for example, if you're running a 5" to 2" reduction (2.5x) it makes it more like 5-1/8" to 2-1/8" (2.4x). Also, link belts shed!

In playing with pulley speeds and stuff I have found my digital tach to be indispensable. Just stick a tiny reflective sticker onto whatever you want to measure and off you go. I've taken repeatable, accurate readings on different things between 30 and 10,000 rpm.

Again, nice work!

yaidunno · Dec 7, 2015

Nice job of using what you have to get things made!

My opinion on the belts is to simply use a traditional style one.

Packard V8 · Dec 7, 2015

Talk about using aerospace hardware to build a matchlock musket - we're proud of you for taking overkill to new GJ highs!

As to belts, I've found when using the smaller diameter pulleys, the notched belts bend round easier.

jack vines

Knyte Tyne · Dec 7, 2015

Macguyver Who?! I know the feeling of... "****... wish I had a [insert tool here] for this..."

Dont know if I missed it somewhere but how you did match up the belt length to the distance between the pulleys? Are they off the shelf or do you order them at the required belt length?

nine4gmc · Dec 7, 2015

Really nice work, looks like it could have been a factory option! As for belts, I prefer the link belts personally, second choice would be a notched standard belt. Stay away from the others. The link belt has MUCH less vibrations and bends around small diameter pulleys great. Standard belts(no notches) vibrate awfully and when you don't use the machine constantly, form a memory shape to the pulley they rest on which causes more vibrations the next time you turn it on. I even tried the lawn&garden green belts and those are worse.

Great job!!

McBrownie · Dec 7, 2015

Thanks everybody. Overkill can be fun. I downloaded a strobe light tachometer app for my iPhone and it worked really well. The actual low RPM is between 714 and 715. I think I'm going to go with the notched v-belts first and then if that doesn't work out, I'll upgrade to link belts. Time to do some measuring.

McBrownie · Dec 7, 2015

Knyte Tyne said:
Macguyver Who?! I know the feeling of... "****... wish I had a [insert tool here] for this..."

Dont know if I missed it somewhere but how you did match up the belt length to the distance between the pulleys? Are they off the shelf or do you order them at the required belt length?

I'm going center to center on the shafts and then enter the pulley diameters. There are a few v-belt pulley calculators out there. I'll post which one I end up using. I'm planning on getting a set of standard ones. If not, then link belts it is.

OCJohn · Dec 7, 2015

McBrownie said:
Here it is with a stack of 6203 bearings held in a place with a 1/2-13 bolt, a 5/8" sleeve to match the I.D. of the bearings, and a couple of washers.
View media item 55374

I love this.

I've been racking my brain trying to understand why everyone seems to make these low-speed pulley conversions with a separate belt adjustment. Your success of leaving it free and just using the motor belt adjustment for both is very affirming.

Thanks for posting.

McBrownie · Dec 8, 2015

OCJohn said:
I love this.

I've been racking my brain trying to understand why everyone seems to make these low-speed pulley conversions with a separate belt adjustment. Your success of leaving it free and just using the motor belt adjustment for both is very affirming.

Thanks for posting.

Thank you. I really liked this idea that I found on vintagemachinery.org too since it only involves one adjustment on the center pulley and the motor can stay where it is:
http://vintagemachinery.org/photoindex/detail.aspx?id=10556

Bobioz1 · Dec 8, 2015

Really nice job on that. Suddenly I see the value in tipping over your belt grinder. Had it pictured as a woodworking maneuver.

McBrownie · Dec 11, 2015

Delayed Gratification!!!!

I ordered both belts this week, the packaged arrived today with........

only one belt.

The other one is on back order and should get here next week. The good news is that the one I have fits. Now I can finish up the center pulley shaft (and continue to wait).

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McBrownie · Dec 12, 2015

I forgot to post the link I used to determine the belts that I needed. Here you go:

http://www.calculatoredge.com/mech/vbelt length.htm

JZiggy · Dec 12, 2015

I'm on pins and needles!!

McBrownie · Dec 13, 2015

I can't believe that Amazon delivers on Sunday, but guess what showed up this afternoon.

Here it is installed:
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It runs very smooth. In fact, it is smoother than the old belt that was on there. Given the age, I guess I'm not surprised. The tachometer shows that I got it down to 274 rpm at the slowest speed. I gave a 2" hole saw a try and could not stall it. No wood smoke either. I also tried a 1/2" drill in a piece of scrap aluminum and got nice twisties like this:
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It has a ton of torque with the 3/4hp motor. I left the middle pulley shaft long in case I ever want to mount a larger pulley up there. At this point, it's all the drill press I need.

Now for the final tally:
Drill press - $50
DP260 Pulley - $45
Pillow Block bearing - $30
Belts - $15
5/8" drill rod - $10
Hardware - $10
Bearings - free

A grand total of a $160. Not bad for a machine that is going to run for years to come. Hope you enjoyed following along.

nine4gmc · Dec 13, 2015

Awesome job! Was the belt delivered by drone?

Sent from my iThingy using Tapatalk

SweetD · Dec 13, 2015

OOHHH wonderful job! Love it! Great ingenuity.

:beer:

Dave

jakemac · Dec 13, 2015

I'm in awe of your ingenuity.
I hope the next generation appreciates just how extra special that DP is now.

Jolomite · Dec 14, 2015

Hey McBrownie- Stellar work! I'd like to ask you some specifics if I might-

How did the 6202 bearings mount in the shaft- their OD made them squeeze in with something like a 'press fit?' Did you have to tap it in?

On the inner Diameter of the 6202 bearings, how snug was everything? (5/8 spacer to bearing tightness, 5/8spacer to 1/2 bolt tightness?) I guess I am trying to wrap my head around how tight these joints need to be to prevent vibration in operation.

Lastly, I'm trying to tell if my eyes are tricking me- the flange bearing in the pillow block- is that flange we can see centered, or sort of off-center/ eccentric? I googled AMI UCFB202-10 5/8 Flange Bearing and see that it probably is centered?

Sorry for the wordy questions, but your work is so handy that I might try this myself. Thank you very much for posting!

McBrownie said:
The column on the Penncraft is on the small side with a 1 7/8" O.D. and an I.D. of a little over 1 9/16". I don't have a lathe (I wish I had a lathe), so I needed to find a way to mount something in the column. More accurate measuring showed that I had 1.570-1.575" for the I.D. Digging around in the shop, I found some old 6203 bearings left over from a Craftsman Block grinder rebuild (or two). 6203's have a 40mm O.D. which is just about 1.575". Perfect!
Since I don't have access to a machine shop, I thought that a pillow block would be the easiet way to get a bearing mounted. I looked at different configurations, and ended up with an AMI UCFB202-10 5/8 Flange Bearing.

I scribed around pillow block, drilled and tapped three 5/16-18 threaded holes for the pillow block and a 1/2-13 threaded hole offset from the center line of the bearing to bolt up the column bearings. This will let the pillow block swing for belt adjustment.
View media item 55370

View media item 55372

McBrownie · Dec 14, 2015

Thank Jolo and everybody. My answers are in blue

How did the 6202 bearings mount in the shaft- their OD made them squeeze in with something like a 'press fit?' Did you have to tap it in?
Yes, they are a press fit, but nothing ridiculous. I had to tap the whole assembly in with a soft-faced hammer. I did have to take the assembly back out once and was able to do so with long screw drivers. So, it is a tight fit, but didn't require a press to put it in. There aren't any up and down forces on it, so it stays in place just fine.

On the inner Diameter of the 6202 bearings, how snug was everything? (5/8 spacer to bearing tightness, 5/8 spacer to 1/2 bolt tightness?) I guess I am trying to wrap my head around how tight these joints need to be to prevent vibration in operation.
5/8" isn't a snug fit on 6203. I also used a 1/2-13 bolt which is a loose fit in the 1/2"x5/8" sleeve too. It all tightened up when I used two washers (top and bottom) that sat on the inner races and "sandwiched" the bearings together. I was worried about a tight fit too, but the washers did the trick.

Lastly, I'm trying to tell if my eyes are tricking me- the flange bearing in the pillow block- is that flange we can see centered, or sort of off-center/ eccentric? I googled AMI UCFB202-10 5/8 Flange Bearing and see that it probably is centered?
Your eyes are correct. I offset the mounting hole (for the bearing bolt) by 1" from the flange bearing center line. This allows the center pulley to "swing" when the belts are being tightened by moving the motor. I had to measure the shaft to shaft distance with the pulley in the middle of it's swing to get the right belt size. I only had about 7/8" swing and I wasn't sure it would be enough to move the belt from groove to groove, but it works fine.

Sorry for the wordy questions, but your work is so handy that I might try this myself. Thank you very much for posting!

You are welcome. The other thing about that pillow block bearing is that the bearing is seated in a movable sleeve almost like a tie rod end. In other words, the shaft coming out of the pillow block can be tilted to make sure it is in line with the spindle and motor bearings. This means that the bearings in the column do not have to be perfectly perpendicular to the spindle and motor shafts. Hope that makes sense.

Give it a try. I really like having slow speeds for metal. It certainly makes the machine feel safer.

Jolomite · Dec 15, 2015

Thanks for the notes! I might just tackle this project for myself. I recently tried to bore a 1/4 hole in some mild steel using a drill press with only a factory two pulley set up. The speed was so great on the lowest setting that I was seeing discoloring on the chips coming out. So, yea, I can see the problems of too much speed.

McBrownie · Dec 15, 2015

Jolomite said:
Thanks for the notes! I might just tackle this project for myself. I recently tried to bore a 1/4 hole in some mild steel using a drill press with only a factory two pulley set up. The speed was so great on the lowest setting that I was seeing discoloring on the chips coming out. So, yea, I can see the problems of too much speed.

Sounds like the fix. The hardest part is finding the correct middle pulley. Is yours a 1/2" or a 3/8" inch belt? Also, pay attention to the pulley diameter. You can post pictures here, or maybe we should start a slow-speed pulley fabrication thread. :beer:

Jolomite · Dec 18, 2015

McBrownie said:
Sounds like the fix. The hardest part is finding the correct middle pulley. Is yours a 1/2" or a 3/8" inch belt? Also, pay attention to the pulley diameter. You can post pictures here, or maybe we should start a slow-speed pulley fabrication thread.

I'll have to look at what pulley width it is. It is a more recent rockwell (1970s?) It has a fairly old style head casting but came with a bright orange plastic belt guard.

I'd love to start that thread. I'm sure there are plenty of others in process as well. I won't be able to touch my that particular DP project until probably February. I have a different one that is almost done- a Homecraft from maybe the 1950s? That speed reduction pulley is a real Frankenstein. I should have that together sooner. Sorry for lack of detail at present. I try to snap some pics over the weekend. :beer:

Roberts210 · Feb 5, 2016

Outstanding job!! Kudos!

McBrownie · Feb 6, 2016

Roberts210 said:
Outstanding job!! Kudos!

Thanks Roberts!

Coolfrayers · May 2, 2016

HI
I recently acquired the drill press just like this. It was sitting in a abandoned barn for probably over 30 years but it's in remarkable shape it also has a stand with it.
Is there a market for these? Debating on selling or keeping it

Coolfrayers · May 2, 2016

Oh, and nice forum

jekquist · May 2, 2016

I need to do this but I may just buy the rouge fab kit.

McBrownie · May 13, 2016

Coolfrayers said:
HI
I recently acquired the drill press just like this. It was sitting in a abandoned barn for probably over 30 years but it's in remarkable shape it also has a stand with it.
Is there a market for these? Debating on selling or keeping it

Cool,

Welcome to the forum. I think the real market is in the variable speed models. But, for the weekend warrior whole uses a hole saw once in a while, the slow speed pulley is really nice.

2oolhound · May 14, 2016

Superbly done modification!! Good gumption in cutting the alu plate by hand. That's the kind of effort and result that makes working with it so much better than veg-ing out in front of the tv in the evenings. :thumbup:

McBrownie · Nov 6, 2016

Thought I would update this thread with the latest changes. This drill press came with a late model 3/4hp Westinghouse motor which wasn't original and never looked right. Plus, it was way too much motor for this DP, not that I ever came close to reaching its limits. So, I was looking for a more period-correct 1/2hp motor. One finally came up and it fits just like it should. I blame the iphone for making the pulleys look like they are out of line with each other.

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This came off of a bandsaw and was running counter-clockwise. I had to swap the motor leads from this:
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to this:
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According the label plate, this motor was originally in a CW setup. The previous owner had the switch rod from the band saw that it was used on. He was nice enough to send it to me and I mounted it up using a scrap piece of cherry. There was room to use it as a chuck key holder too.

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It is much safer than reaching around to the back of a running machine. The only thing left to do is to get a 4L230 belt to replace the 4L240 that I used with the 3/4hp motor. The 1/2hp motor is a little smaller and can use a shorter belt.

nine4gmc · Nov 6, 2016

Awesome McB! Love that vintage remote control switch!

bubinga · Nov 6, 2016

Nice job!
sure does look factory

Cleave · Jul 11, 2018

Excellent job on the project, and great write up.

I am a new member here, (early career mechanical engineer) first post, and am considering a similar geardown for my 11" Homecraft drill press.

And yes, not only could you tow a car with your bearing link, you could lift the car, with a 5:1 safety factor... (rigging by others).

McBrownie · Jul 11, 2018

If you like my caveman solution for speed reduction, here is the next level:

This is a reboot of a product that was produced in the 60's. Tubalcain/Mr. Pete has an original and has refurbished it to a functional level. I'm waiting to see if some home machinists come up with a newer version that works without throwing oil all over the shop.

bubinga · Jul 11, 2018

Cleave said:
Excellent job on the project, and great write up.

I am a new member here, (early career mechanical engineer) first post, and am considering a similar geardown for my 11" Homecraft drill press.

And yes, not only could you tow a car with your bearing link, you could lift the car, with a 5:1 safety factor... (rigging by others).

Again, Nice work!

Sent from my MotoG3 using Tapatalk

Cleave · Sep 7, 2018

I just finished my own Delta Homecraft 11" slow speed pulley mount and will post the pictures once I get up to 5 posts on here.........

https://www.garagejournal.com/forum/showthread.php?p=7412888#post7412888

Penncraft Drill Press (Delta Homecraft) Slow Speed Pulley Build

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