Spindle scribing sled.

[Jar944]

Started building this sled last week, while testing everything out i noticed slight inconsistencies in the scribe height (basically up to .004" / .005" variation) I ended up tracing it to the side clamp. It's effecting how the part sits against the base of thr sled and causing the far end to twist/lift slightly. I added a clamp to the far end to test and it kept everything consistent so I'll be adding a additional clamp cylinder to the operator side of the sled. The issue didn't happen on short 6-10" rails.

 

[Jar944]

Added another clamp cylinder to solve the height variations I was getting.

 

[DBC]

Cool sled. A lot more impressive than my beaten up old plywood coping sled with one mechanical clamp. I work in metric and if I am doing the conversion right you are trying to make a 1/10th of a mm improvement on performance. You are a lot more precise than me. I make those sort of adjustments after the glue up with sandpaper.

 

[Jar944]

Cool sled. A lot more impressive than my beaten up old plywood coping sled with one mechanical clamp. I work in metric and if I am doing the conversion right you are trying to make a 1/10th of a mm improvement on performance. You are a lot more precise than me. I make those sort of adjustments after the glue up with sandpaper.

You are correct the deviation was 0.127mm. Certainly not a significant issue, and could easily be sanded/planed until flush. My goal is to get everything as consistent as possible.

My old mdf sled was very inconsistent because it would flex slightly with any variation in clamping pressure. That inconsistency was the reason I built this sled.

 

[guineafowl21]

I like the air cylinders! I made a sled much like your original one, with toggle clamps. Do you use a spelch (breakout) piece?

 

[Spectric]

It looks good but would you not be better off using aluminium extrusion which is more stable than wood, especially if looking at tight tolerances.

 

[Jar944]

It looks good but would you not be better off using aluminium extrusion which is more stable than wood, especially if looking at tight tolerances.

Yes, this is just the prototype. I wanted to make sure everything worked how I wanted before I machined the rest of the sled. The sides and clamp mounts will be 6061, the top bars will be 1018 cold rolled.

 

[Jar944]

I like the air cylinders! I made a sled much like your original one, with toggle clamps. Do you use a spelch (breakout) piece?

Yes, both the old sled and new sled have backing blocks. I scribe after profiling so I'm running both right and left scribes.

 

[Spectric]

Nice to still see things being designed and thought out, rather than just buying something off the shelf.

 

[Adam W.]

What are you making with such fine tolerances ?

 

[Jar944]

What are you making with such fine tolerances ?

Cabinets typically.

The end product does not have anything close to those tolerances, but the machine setup should be as accurate as possible. It just makes things easier / faster down the line. I have a few dial indicators and calipers I use for setup and expect to be able to get the machines to cut within a few thousandths.

 

[guineafowl21]

When you do the profiles, do you run them on a spacer piece to get them the same height as the scribes, or change the cutter height? And if the latter, do you bother with dial gauge, or just eyeball it?

 

[Jar944]

When you do the profiles, do you run them on a spacer piece to get them the same height as the scribes, or change the cutter height? And if the latter, do you bother with dial gauge, or just eyeball it?

The profile is run first and face down again the table, it's just eyeballed for height. The scribes are run on separate machines and height adjusted with a caliper and dial indicator to get the height exact.