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J. R. Williams
08-03-2012, 06:16 PM
I have fabricated a high speed spindle unit that is driven by my milling machine's spindle and need a better drive belt. The spindle is from a New Hermes pantograph unit. I have been using a 3/8" inch wide x 18" long timing belt running it on the smooth side. This belt is not satisfactory. One supplier of thin flat belts has one in stock but has a $25 minimum order for an $8 belt. Any good source for a belt? A vacuum cleaner belt might work but none of the vendors list the length of their belts.

JRW

sasquatch
08-03-2012, 07:48 PM
We'd like to see a pic or two of this set up you built?

Arthur.Marks
08-03-2012, 08:04 PM
Every small spindle such as you mention (~3/8" wide belt pulley) uses a round, polyurethane thermoplastic belting that I am aware of. It can be joined to any length necessary with a flat-tipped solder iron and a homemade jig. There are commercial joining jigs, but they are horrendously expensive. For example, I have a swiss cartridge drilling/grinding spindle that uses ⌀6mm belting I bought from McMaster.

[EDIT] Just looked---didn't realize standard v-belts went down that small. 2L (1/4" wide) or 3L (3/8" wide) are listed with McMaster (http://www.mcmaster.com/) in inch increments 11" and longer. They also list flat belts 3/8" width in the same thermoplastic material I mentioned initially. They can be joined to any custom length as necessary.

Toolguy
08-03-2012, 08:57 PM
You could get 3 $8 belts for $25 and have a couple of spares.

J Tiers
08-03-2012, 09:15 PM
WM Sopko in Cleveland OH has lots of good flat belts. But they also have a minimum.....

J. R. Williams
08-03-2012, 10:10 PM
Arthur
The engraving spindle is equipped with a flat bottom pulley. The belt I am using is a timing belt run with the normal outside running inside. The flat or round urethane belt material comes in long lengths and requires the correct tools to heat weld the joint. I tried a large cross section O ring but it stretches with increase in speed. I will post a photo when The unit is fully operational.
JRW

Arthur.Marks
08-03-2012, 11:25 PM
I wonder if you couldn't just buy an automotive multi-vee belt ("serpentine") of the correct length. Then, flip it inside out and carefully cut off the necessary number of vee's to get your correct width. I do have experience with the Gates brand poly-vee (or whatever one wishes to term them) which I purchased from a local CarQuest. I was pleasantly surprised at their power transmission! The vee's would provide a very clear and convenient cutting reference for reducing the width with an X-Acto.

Also worth mentioning that I have access to one of those Eagle belting kits which can join the flat as well as my round urethane belting. If you want to try one of the urethane flat belts, I'd be happy to join one for you. It would be no trouble. I would just need the material or reimbursement for such.

Mr Fixit
08-04-2012, 12:09 AM
J.R.
I have a SB lathe that uses a flat belt and what I have done (idea from yahoo site) is take a flat serpentine belt for a car engine and cut it at a 45* angle at the length I needed then used super glue to put the cut back together on the machine and it has been working for a few years with no problems at all. I have stalled the machine with my inexperence and have run it at a very fast speed to turn some wood once and still no problems. You may want to use Arthurs idea of cutting to width and mine of cut to length. most you will be out is a bit of time and maybe $15.
Please do let us know what you do and post those pics.

Best of luck Chris
Mr fixit for the family

Arcane
08-04-2012, 12:58 AM
I have fabricated a high speed spindle unit that is driven by my milling machine's spindle and need a better drive belt. The spindle is from a New Hermes pantograph unit. I have been using a 3/8" inch wide x 18" long timing belt running it on the smooth side. This belt is not satisfactory. One supplier of thin flat belts has one in stock but has a $25 minimum order for an $8 belt. Any good source for a belt? A vacuum cleaner belt might work but none of the vendors list the length of their belts.

JRWCurious...why is it not satisfactory?

J. R. Williams
08-04-2012, 01:02 AM
Chris
The type of flat belt I want is at most 0.050 inch thick. The automotive serpentine belts are much thicker and would not work over a pulley less than one inch in diameter. I have a small bench top drill press that I fitted with flat pulleys and use an automotive multi-v belt. The high speed engraving tool does not take much power and needs high RPM for good cutting.
JRW

Evan
08-04-2012, 01:11 AM
I have cut down Poly-V belts to runs spindles up to 40k rpm. They work well and are easy to split including down to just one rib.

lakeside53
08-04-2012, 01:15 AM
Yes.. Ignore "automobile serpentine" belts. They are usually K or L section. Just get a J section poly-vee. Same thing, much thinner/flexible.

darryl
08-04-2012, 01:19 AM
You could buy some rubber sheet and cut a strip from it, then ca it together with two of the tiniest drops of ca. Then slip it onto any round thing that is about 6 inches in diameter. That's just to hold it round and in place. After that you smear some shoo goo onto it and quickly wind a nice flat layer of polyester thread, then smooth it over with the shoo goo.

For a really nice job you would machine up a disc to hold the belt. Without removing the disc from the lathe, slip the belt onto it and apply the shoo goo and thread. Before removing it, you give it a surface grind to even out the thickness and trim the width if need be.

I have done similar to this several times with good results. I've used tool handle coating mostly for this, and it seems to hold and work well. I've used dental floss for cord, and what they used to call 1/2A flying line. That's a dacron cord.

You end up with a flat belt with virtually no stretch and with a grip surface on it.

At one time I ended up with a roll of rubber tire patch material, and I made a few belts from that. Goop, or shoo goo, bonds with it quite well.

One caveat- when you wind the layer of cord on, just do one layer. Don't overlap and wind back over that for more cord. It works against you. When you consider the breaking strength of one strand, then multiply that by 10 or 20 or more strands, the belt will be plenty strong enough.

FatWheels
08-04-2012, 01:39 AM
Here's a vote for vacuum cleaner belts. I have a local vacuum cleaner store with an entire peg
board of belts in a wide range of sizes. I've taken my old belt and matched it up with no problems. Nice thing is they are about three bucks apiece as well. Call around, others might just have the same selection in your area.

regards,

Jim

Ian B
08-04-2012, 04:59 AM
JR,

How about this? http://www.lathes.co.uk/page4.html

Haven't bought any from him, maybe others have?

Ian

beanbag
08-04-2012, 05:45 AM
Excuse me for this minor threadjack, but what is the best belt type for these small, high speed spindles? For example, the fast end turning at 10-20K rpm?

lynnl
08-04-2012, 12:29 PM
Contact these people:
http://www.brecoflex.com/

Evan
08-04-2012, 12:53 PM
what is the best belt type for these small, high speed spindles?

High durometer o-rings work well. Standard neoprene (Buna N) 0-rings are too soft and stretchy (70 durometer). They will stretch off the driven side as the centrifugal effect throws it away from the pulley. They work fine for low rpm but need a lot of stretch adjustment. One of the best is 90 durometer urethane but it does have one downside. It easily takes a set so if it is left under tension it will develop a flat spot if left for a while. EPDM is excellent with high wear and set resistance. Silicone wears out too fast.

It is possible to get Buna N in 90 durometer but not everyone has them.

Weston Bye
08-04-2012, 01:45 PM
Try McMaster-Carr, enter this stock number: 6082k51
NBR rubber coated nylon fabric. .031" thick.

I've used these, should do your job.

They don't have 3/8 wide, but you might try a 1/4 or consider cutting down a 1/2.

beanbag
08-04-2012, 07:54 PM
Why would a round cross section be good, and why not something that doesn't stretch, like "NBR rubber coated nylon fabric. .031" thick" that weston mentioned?

Evan
08-04-2012, 08:12 PM
You don't have to worry about a round belt rolling over. You need some stretch (not much) to maintain tension, reduce torque ripple and vibration. Of course, all belts have some stretch. My SB lathe came equipped with a belt that was rubber on one side and a coated fabric on the other about a 1/16" thick total x 1" wide. It was a great belt and lasted me nearly 20 years. It had very little stretch and excellent traction but it finally started to come apart at the splice. That type of belt would be ideal for a high speed spindle if you could find the material. One of these days I will ask my cousin in law. He has worked in the belting business for decades.

J. R. Williams
08-04-2012, 10:57 PM
I have ordered a belt from McMaster per the note from Weston and it will be shipped Monday.
JRW

J. R. Williams
08-10-2012, 10:08 PM
Weston
I received the small belt from McMaster and it does a satisfactory job. I wanted to obtain an endless woven belt and the McMaster one has a lap splice which does not seem to cause any problem I have a small spindle pulley of 0.810" OD and a drive pulley of 4.25 inches OD.

JRW


Try McMaster-Carr, enter this stock number: 6082k51
NBR rubber coated nylon fabric. .031" thick.

I've used these, should do your job.

They don't have 3/8 wide, but you might try a 1/4 or consider cutting down a 1/2.