Bearing / Linear Motion Design?

Design of structural and load bearing framework.
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larry104
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Re: Bearing / Linear Motion Design?

Postby larry104 » Sat Jan 08, 2011 1:43 am

For the X axis you could easily install it under the table and protect it that way (ref a drawing a few pages back). As for a bearing running on a flat surface (what you are proposing) - I would say you will have even more problems with dust - or?

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beermkr
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Re: Bearing / Linear Motion Design?

Postby beermkr » Sat Jan 08, 2011 2:41 am

I am just worried that the fact that it is concave will allow it to collect up the dust vs being able to brush it off. Not dismissing it. Just an observation.
Mike Pensinger
Chief Brewer, The River Company Brewery, Radford, VA

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larry104
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Re: Bearing / Linear Motion Design?

Postby larry104 » Sun Jan 09, 2011 5:03 pm


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Awesomeness
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Re: Bearing / Linear Motion Design?

Postby Awesomeness » Thu Jan 13, 2011 10:05 pm

Beermkr,
Now that you've built a test of your bearing design, how is it working out? What observations about it, or improvements have you noticed?

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beermkr
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Re: Bearing / Linear Motion Design?

Postby beermkr » Fri Jan 14, 2011 1:17 pm

It rides very nicely and lends itself well to adjustments when the guy at lowes undercuts your table by a half and inch :(

I have not run the table yet as I am still working on the X drive system. I went with belts to keep the cost down and improve speed without whipping issues.

The cost is so low that I am am big fan of building the new machine to use belts as much as possible. The Y and Z axis hardware cost me over $175 (Acme 2:1 and DumpsterCNC parts) where the X axis will be under $80 and driven from both sides.

100_0860.JPG
Mike Pensinger
Chief Brewer, The River Company Brewery, Radford, VA

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larry104
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Re: Bearing / Linear Motion Design?

Postby larry104 » Fri Jan 14, 2011 5:55 pm

Hi beermkr,

which exact belt and pulley's did you use?

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beermkr
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Re: Bearing / Linear Motion Design?

Postby beermkr » Fri Jan 14, 2011 6:30 pm

I used the 14 tooth XL pulley from Mcmaster Carr. The belt is the 3/8 wide version. The idlers are skate bearings on a 5/16th bolt with an oversized 1/4 washer to create a standoff.

57105K14 Acetal Pulley for XL-Series Timing-Belt, for 1/4" & 3/8" Belt Width, 1.13" OD, 14 Teeth 7.51 ea.
1840K1 XL, L, H, and AT10 Urethane Belting, XL Trade Size, .200" Pitch, 3/8" Width 2.43/foot
9946K11 Aluminum Set Screw Shaft Collar, 1/4" Bore, 1/2" Outside Diameter, 5/16" Width 1.82 ea.
60355K44 Steel Ball Bearing--ABEC-1, Double Shielded, No. R4a for 1/4" Shaft Diameter, 3/4" OD 5.86 Each
8888K36 A2 Tool Steel Tight-Tolerance Rod 1/4" Diameter, 3' Length (Same as 8888K361) $6.74 ea

2 Pulleys, 2 collars, 18 feet of belt (could have done it with 15 easily), 2 bearings, and one piece of drill rod. I will let you guys do the math.

I have the CamBam and NC files for the mounts if anyone wants them. I have attached the .cb files here.
Attachments
X Belt Drive Mounts.cb
Direct attachment to a standard "book machine" Just replace the bolts at the bottom of your gantry with 3/4" longer bolts.
(31.57 KiB) Downloaded 649 times
Mike Pensinger
Chief Brewer, The River Company Brewery, Radford, VA

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larry104
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Re: Bearing / Linear Motion Design?

Postby larry104 » Sat Jan 15, 2011 1:47 am

Hi beermkr,
was there a specific reason why to choose to use two motors instead of a single motor in the middle of the gantry?

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beermkr
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Re: Bearing / Linear Motion Design?

Postby beermkr » Sat Jan 15, 2011 3:13 pm

There is only one motor. The setup is just like the BlueChick. Motor mounted to one side with a coupler, 1/4" drill rod and bearing supports at the other end.
Attachments
100_0863.JPG
Mike Pensinger
Chief Brewer, The River Company Brewery, Radford, VA

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larry104
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Re: Bearing / Linear Motion Design?

Postby larry104 » Sat Jan 15, 2011 5:20 pm

Ahh, I see. Since I would like to have a slot in the table to be able to cut dovetails into the edges of boards (in other words keep the bottom of the table clear of moving parts) would there be a fundamental reason not to put the motor into the middle of the gantry in your opinion?


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