Scratching head - Drill Press belts.....???

[Crow Horse]

After cleaning up my newly acquired used Central Machinery drill press (#38144) (13", 16 speed floor model), I decided to replace the old belts. Easy peasy, right? Nope.

It calls for a M24 & M25 belts, the same that is currently on it. Ordered and received the new belts but when I went to swap them out, no joy. Too short.

I understand that belts do stretch over time but not to the extent that the originals have. The M24 belt measures app. 25.25" (outside circumference) and the M25 measures a 27.25". WTH?

I used a fabric tape measure which is about 1/4" off but that shouldn't matter in this application. And yes, I did "retract" the motor to remove the belts.

Any ideas as to what's going on? I'll be purchasing a different combination of belts to make it work but I'm perplexed as to why this has become such a problem.

 

[RTM]

With my shop fox drill press, I had to do something weird to change the belt, leverage the motor in with a bar to get the belt to fit. Just retracting wasn’t enough, there was a spring or something that needed to be compressed to get the belt back on. Forgot what I used, but it was awkward as heck to do in place, alone.

 

[Sumboodie]

Belts don't stretch much. They wear which makes them sit lower in the pulley, effectively making the length needed be shorter.

 

[RogueFab]

Belts have 2 "names" for their size, one is the pitch diameter in inches, the other is a senseless NAME they give the belt that is usually some arithmetic difference from it's actual size. On A(1/2) and 3L (3/8) Belts, these have names like A17 for a 19" pitch diameter belt and 3L33 for a 35" pitch diameter belt. I've been using belts for a while, and burned myself with this many times. It is super annoying.

Get or make a belt measurement tool... I haven't but should!

 

[Davefr]

Don't forget that some belts are sized by Pitch and others are sized by O.D.

Pitch is < O.D.

I got stung by purchasing an "A" series belt thinking is was sized the same as 3L belts.

 

[quickfarms]

Where did you get the belts from?

What I do is just take the old belts to an industrial bearing supply that is around the corner and they either have of get me the correct belt.

Belts do stretch a lot under certain circumstances but a drill press is probably not one of them

 

[lilredex]

Before I got my belt measurer like this one:

https://johnbrooks.co.nz/v-belt-measurement-device

I used to stretch the new on top of the old between my thumbs to check for compatibility (length). This is a good check, but really doesn't tell you much about the actual size.

So I made one. It consisted of a wooden circle about 4 1/2" in diameter cut in half and grooved on the back to ride on a stick. One piece was permanently fixed. To calibrate, I measured a few belts of known length then marked it on the stick, and filled in the missing values which turned out to be about an inch apart. That device was surprisingly accurate even though the circle's business end was flat and not grooved.

 

[Crow Horse]

I purchased the belts from Belt Palace. The belts received are spot on regarding the measurements. I contacted them and this is part of their reply:

"Sometimes these imported belts don’t conform to US numbering standards and we get issues like this......."

Regardless of what the operator's manual states, the bottom line is to find belts that will fit the pulley system properly. I believe the combination I require is a 25" & 26" belt length. That should make adjustments easier and allow proper tensioning.