Tension for belt on drill press
- Thread starter WWShop
- Start date
Yep, I've even heard reports of some of those really small cheap 1/3 HP DPs not being able to start if it's on the highest speed setting and the belt is a little too tight.
To WWShop. This is only a really rough guide, but for a typical length single belt DP like that I usually gauge it with thumb pressure. Resting the palm of my hand on the guard and pushing with just my thumb, I'm looking for about 1/2" to 1" deflection on the belt at the mid way point.
Less then 1/2" deflection and I'd normally consider it a bit tighter than necessary. If it's getting up toward 1" deflection then too loose. As I say, that's only a really rough guide, for shorter belts (like in a three pulley setup) I'd scale that down a bit.
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That little belt doesn't need a lot of tension. It's hard to explain but just snug it up so there's some deflection but not sloppy.
Do yourself a favor and order an extra belt to have on hand. It's a real oddball size and who knows how long it'll be available.
FigureItOut
Well-known member
I've been putting too much tension on Delta's belt, I've just learned.
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djb2
Well-known member
V belts work by creating their own pressure as they are drawn into the groove.
If the geometry and materials are correct, they need only a tiny amount of initial tension to start working. Under higher loads, they pull themselves deeper into the groove, creating more pressure and thus grip.
If you start out with high initial tension the belt will constantly be deep into the groove, resulting in high friction and wear on the bearings, belt and pulleys.
If the belt is slipping, check for a heat-hardened belt or a pulley with worn grooves. Rather than increasing the tension, fix the problem and decrease the tension to prevent the problem from recurring.
If the geometry and materials are correct, they need only a tiny amount of initial tension to start working. Under higher loads, they pull themselves deeper into the groove, creating more pressure and thus grip.
If you start out with high initial tension the belt will constantly be deep into the groove, resulting in high friction and wear on the bearings, belt and pulleys.
If the belt is slipping, check for a heat-hardened belt or a pulley with worn grooves. Rather than increasing the tension, fix the problem and decrease the tension to prevent the problem from recurring.
rsanter
Well-known member
Light or medium tension. You don't want it to slip when drilling but if the bit grabs then you do want it to slip
Bob
Bob
I just looked and the belt can still be ordered through Sears, so I will probably order several. I looked online, and on a different forum a person said they took a serpentine belt, of the same length, and he cut off a section and he said it fit perfect.
Another question: I paid $130 for it and it is in very good condition. Did I do ok on the price?
Kensgarage
Banned
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- Sep 30, 2015
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You got a good press at a fair price.If you have a fishing scale---6 lbs of belt tension.If not ? grab a gallon jug that's 3/4 full and lift it with one finger. About that much. CloserNuffer.
Provincial
Well-known member
I have a similar Craftsman drill press, model #113.21370. It uses that same small belt, mine is about 45" long. I replaced my belt with a Gates 5M1150 belt, which is 45.28" long according to the book.
Your Gates dealer will likely have to special order these belts. NAPA may be able to get them on a special order, since they also handle Gates products, rebranded. I got mine on the internet by looking up the part number.
I have had my drill press since 1973 and always adjusted the belt slightly tight. I also relieved the tension whenever I wasn't using the drill. My original belt broke in 2008.
Your Gates dealer will likely have to special order these belts. NAPA may be able to get them on a special order, since they also handle Gates products, rebranded. I got mine on the internet by looking up the part number.
I have had my drill press since 1973 and always adjusted the belt slightly tight. I also relieved the tension whenever I wasn't using the drill. My original belt broke in 2008.
How exactly does that work Kensgarage? I mean, where about do you measure the 6 lbs?
With cars when they specify a force measurement for v-belt tension, they usually specify a sideways force at a given deflection at the middle of the longest part of the belt. Are you sure you don't mean 1/2" deflection at 6 lbs force or something like that?
Hornman
Well-known member
I am a fan of keeping spare belts on hand. I take the spare and write up a data card on the belt listing what machine it goes to and any engineering data available, then vacuum pack the belt and card with my Foodsaver. The vacuum packing slows down oxidation and rot. Plus, it makes it hard to lose the data card.