Guides / Process

Bar Feeders on Swiss-Type Lathes and How They Affect Your Quote

September 21, 2026

A bar feeder is the unglamorous machine behind every Swiss machining cost figure that depends on unattended running time. It is what lets a Swiss-type lathe cut part after part for hours without an operator standing at the machine, and its type and condition quietly shape several lines on a quote that buyers rarely think to ask about.

What a bar feeder does

A bar feeder holds a length of round bar, typically several meters, and pushes it into the machine’s headstock as the previous part finishes, keeping the spindle fed without a manual reload. Combined with the guide bushing supporting the bar right at the cut, covered in the pillar guide, the feeder is what turns a Swiss-type lathe from a machine that makes one part at a time into one that runs a production quantity with minimal attention.

Without it, an operator would have to load and clamp a new piece of bar after every part or every few parts, which defeats the cycle time economics that make Swiss machining pay off at volume in the first place.

Feeder types

Hydrodynamic feeders float the bar on a cushion of oil inside a guide channel, which damps vibration and lets the bar run at high spindle speed with less noise and less whip, particularly useful on longer, more flexible bar. Common on production Swiss work where speed and surface finish both matter.

Vacuum clamp feeders use vacuum to grip and advance the bar through a series of guide channels, generally simpler mechanically and well suited to a wide range of bar diameters without changing much hardware between jobs.

Magazine or short bar feeders load pre-cut shorter lengths of bar rather than a single long piece, useful when bar length is constrained by material availability or when running a material only stocked in shorter standard lengths.

The differences mostly affect how the shop runs its own operation rather than anything you specify on a drawing. What matters to you is whether the shop’s feeder setup fits your part’s diameter, material and required bar length, not which type it uses.

Bar length and unattended running time

Longer bar means fewer changeovers. A shop running 12 or 13 foot bar changes stock far less often than one running shorter lengths, which translates into more genuinely unattended machine time and, at volume, a real difference in labor cost per part.

Bar length availability varies by material. Common grades in common diameters are usually available in standard long lengths. Specialty alloys or unusual diameters sometimes come only in shorter standard mill lengths, which increases changeover frequency regardless of the feeder’s own capability. This is one more reason material choice reaches deeper into a quote than the price per kilogram alone, alongside the points covered in the materials guide.

Remnant waste

Every bar leaves a piece too short for the feeder to advance into another finished part, the remnant covered in the cost guide and the guide bushing article. Longer bar spreads that fixed remnant loss over more finished parts, so a shop running longer stock wastes a smaller percentage of material than one running shorter bar, all else equal.

On inexpensive material like brass this barely registers. On titanium or a certified medical alloy, where the material itself is a major cost line, bar length and the resulting remnant percentage genuinely move the quote. It is worth asking a shop quoting an expensive material what bar length it plans to run and how many finished parts it expects to get from each bar.

Changeover between jobs

Switching a Swiss machine from one job to another involves clearing the old bar, loading new stock into the feeder, and reconfiguring the feeder’s guide channels for the new diameter if it differs from the previous job. This changeover time is part of the setup cost covered generally in the minimum order quantity guide, and a shop that runs your diameter regularly has less changeover friction than one setting up for an unusual size for the first time.

What this means for your RFQ

None of this needs to appear on your drawing. Bar feeder type and configuration are the shop’s operational decision, not a specification you provide, the same way you would not typically specify which collet or tool holder brand a shop uses.

What is worth asking, particularly on an expensive material or a high volume program:

• What bar length does the shop typically run for this material and diameter
• How much remnant does the shop expect to leave per bar, and how does that translate into material cost per part
• Does the shop’s feeder setup already fit this diameter, or would it need reconfiguration

These questions give you a more complete picture of a quote’s material line than the per kilogram price alone, particularly on parts where material is a significant share of the cost, and they cost nothing to ask during an otherwise ordinary RFQ conversation with a candidate shop.

Short bar and remnant handling strategies

Not every job runs on the longest bar a feeder can handle, and understanding why helps explain a quote that assumes shorter stock than you might expect.

Material availability constraints. Some specialty alloys and unusual diameters are only readily available in shorter standard mill lengths, regardless of what the shop’s feeder could technically handle, which means the bar length decision is sometimes made by the material supply chain rather than by the shop’s own equipment, the same material availability point covered in the materials guide.

Shop floor space and handling. Very long bar, sometimes exceeding the length of the machine and feeder combined by a significant margin, needs supported handling from storage to the machine, and a shop’s floor layout and material handling equipment can practically limit how long a bar it runs even when longer stock is available to purchase.

Job mix and changeover frequency. A shop running many different parts in smaller batches, rather than a few parts at very high volume, sometimes standardizes on a moderate bar length across jobs to simplify feeder reconfiguration between changeovers, trading a small amount of remnant efficiency on any single job for faster, more predictable changeovers across its whole operation.

None of this is something to specify on your drawing. It is useful context for understanding why a quote’s material line might look different between two shops even when both are quoting the same grade and diameter, one more example of the process decisions covered in the comparing quotes guide that explain quote differences without either shop being wrong.

How feeder setup affects quoting a new job

When a shop quotes a new part, part of what it is implicitly pricing is whether your part’s bar diameter and material fit its existing feeder configuration or would require reconfiguration.

A shop already running your exact bar diameter regularly, for other customers or other parts, has essentially no feeder-related setup friction to add to your job. A shop encountering your specific diameter for the first time, or needing to reconfigure guide channels sized for a different range, absorbs that adjustment somewhere in the quote, typically folded into the general setup charge covered in the minimum order quantity guide rather than broken out as its own line.

This is one more reason that a shop’s stated experience with parts similar to yours, in both material and diameter, is worth asking about directly during quoting, alongside the material-specific experience questions covered in the comparing quotes guide. A shop for whom your diameter is already routine is starting from a more favorable position than one for whom it is a first-time setup, even before either shop begins optimizing cycle time on the part itself.

Feeder reliability and unattended run length

A feeder’s mechanical reliability directly sets how long a Swiss machine can genuinely run without an operator checking on it, which matters more the higher your volume runs. A feeder prone to jams or misfeeds, whether from wear, poor maintenance or a mismatch with the specific bar being run, forces more frequent operator attention regardless of how well everything else about the job is set up, quietly eroding the unattended running time advantage that makes Swiss machining economical at volume in the first place. This is one more reason a shop’s overall equipment maintenance discipline, not just its machine count, is worth weighing when comparing candidates for a high volume program, alongside the other operational signals covered in the comparing quotes guide.

A quick reference before you quote

None of the mechanics covered in this guide belong on a drawing. What is worth carrying into an RFQ conversation is a short mental checklist: confirm the shop’s typical bar length for your material and diameter, ask how much remnant it expects to leave per bar on an expensive material, and treat changeover friction as one more reason a shop already running parts similar to yours tends to quote more competitively than one encountering your specific setup for the first time.

Getting parts quoted

Send the drawing, material and yearly volume through the RFQ form. We match your part with up to three shops that run Swiss-type lathes and reply within 24 business hours.

For the fuller picture of how material and bar condition reach your quote, the cost guide walks through the whole calculation with a worked example.

Frequently asked questions

Keep reading

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